Document Type] Spccificatioil
[Title oC the Invention] CIIEMICAL TREATMENT STEEL SHEET, AND
METHOD FOR PRODUCWTG CHEMICAL TREATMENT STEEL SHEET
[Technical Field or the Invention]
[OOOl]
The present invention relates to a chemical treatment steel sheet, and a
method for producing a chemicai treatment steel sheet.
Priority is claimed on Japanese Patent Application No. 2014-207922, filed on
October 9,2014, the content of which is incorporated herein by reference.
[Related Art]
[0002]
When colltinuously using a metal, there is a concern that corrosion may occur.
In the related art, various technologies are suggested so as to prevent corrosion from
occurring in a metal. Examples of the technologies which are suggested include a
technology of performing plating with respect to a metal sheet, and a technology of
performing various surface treatments with respect to a surface of a metal sheet or
plating.
[0003]
Here, aNi-plated steel sheet, a Sn-plated steel sheet, a Sn-based alloy plated
steel sheet, and the like are used to manufacture a metal container that is intended to
preserve drinks or food.
In a case of using aNi-plated steel shect, a Sn-plated steel shect, or a Snbased
alloy plated steel sheet as a steel sheet for metal containers (hereinafter, referred
to as "steel shect for containers") that is intended to preserve drinks or food, a chemical
treatment is performed with respect to a surface of the plated steel sheet with
hexavalent chromiuni so as to secure adhesion between the steel shcct and a coating or
a film, and corrosion resistance in many cases. 'The chemical treatment using a
hexavalent chromium-containing solution is referred to as a chromate treatment.
[0004]
However, the hexavalent chromium that is used in the chromate treatment is
harmful in an environmental aspect, and thus a chemical treatment film such as Zrphosphorous
film has been developed as a substitute for the cluomate treatment that is
performed for the steel sheet for containers in the related art. For example, Patent
Document 1 discloses a steel sheet for containers which includes a chemical treatment
film that contains Zr, phosphoric acid, a phenol resin, and the like.
[Prior Art Document]
[Patent Document]
[OOOS]
[Patent Document 11 Japanese Unexamined Patent Application, First
Publication No. 2007-284789
[Disclosure of the Invention]
[Problems to be Solved by the Invention]
[0006]
In a case of using the chemical treatment steel sheet, in which the chemical
treatment film disclosed in Patent Document 1 is formed on a surface of a Sn-plated
steel sheet, as a steel sheet for containers intended to store acidic content? such as
acidic fruit, it is possible to use the chemical treatment steel sheet in a state in which
the chemical treatment film and the contents come into direct contact with each other
without carrying out coating on the surface of the chemical treatment film. Since
coating is not performed on the surface of the clicmical treatment film, Sn that is eluted
fro111 the Sn-coated steel sheet and 0 2 in the contents cause a reaction, and thus it is
possible to prevent oxidation of the contents.
However, from a rcsult of examination by thc present inventors, the present
inventors have obtained the following finding. Since the chemical treatment iilm, in
which a surface is not subjected to coating, is discolored and turns yellow (yellowing)
in accordance with a variation with the elapse of time, there is a problem in that the
exterior appearance deteriorates.
In addition, in a case of using the chemical treatment steel sheet, in which the
chemical treatment film disclosed in Patent Document 1 is formed on a surface of a
Sn-plated steel sheet, as the steel sheet for containers, the chemical treatment steel
sheet is required to have additional corrosion resistance.
[0007]
The invention has been made in consideration of the above-described
circumstances, and an object thereof is to provide a chemical treatment steel sheet
having excellent yellowing resistance and corrosion resistance, and a method for
producing the chemical treatment steel sheet.
[Means for Solving the Problem]
[OOOS]
The invention employs the following means to solve the above-mentioned
i
I problems and to accomplish the object.
i
[0009]
(1) According to an aspect of the invention, a chemical treatment steel sheet
I
i
includes: a steel sheet; a composite coated layer which is formed on at least one :
surface of the steel sheet, and contains 2 to 200 mg/m2 of Ni in tenns of an amount of
n~etaNl i and 0.1 to 10 g/in2 of Sn in terms of an amount of metal Sn, and in which an
island-shaped Sn coated layer is formed on a Fc-Ni-Sn alloy layer: and a chemical
treatment layer that is lbrmed on the composite coated layer, and contains a 0.01 to 0.1
mg/m2 of Zr compounds in terms of an amount of metal Zr and 0.01 to 5 mg/m2 of
phosphate compounds in terms of an amount of P.
[00 101
(2) In the chemical treatment steel sheet according to (I), the chemical
treatment layer may contain 0.08 mg/m2 or less oSZr compounds in terms of the
amount of metal Zr.
[OOll]
(3) In the chemical treatment steel sheet according to (2), the chemical
treatment layer may contain 0.06 mg/m2 or less of the Zr compounds in terms of the
amount of metal Zr.
[0012]
(4) In the chemical treatment steel sheet according to any one of (1) to (3), the
chemical treatment layer may contain 0.02 mg/m2 or more of the Zr con~poundsin
tcrms of the amount of metal Zr.
[0013]
(5) In the chemical treatment steel sheet according to any one of (1) to (4), the
chemical treatment layer may contain 4 mg/rnz or less of the phosphate compounds in
terms of the amount of P.
[0014]
(6) In the chemical treatment steel sheet according to any one of (1) to (5), the
chemical treatment layer may contain less than 1 mg/m2 of the phosphate compounds
in terms of the amount of P.
[00 1 51
(7) In the chemical treatment steel sheet according to any one of ( I ) to (6), the
chemical treatment layer may contain 0.03 mg/m2 or more of the phosphate
compounds in terms of thc amount of P.
[0016]
(8) In the chemical treatment stccl sheet according to any one of (1) to (7),
when a variation amount in a yellowness index before and after storage for 4 weelts in
an environment of a temperature of 40°C and a humidity of 80% at one measurement
point on an outermost surface of the chemical treatment layer is set as AYI, an average
value of the AYI obtained at the measurement points included in a unit area of the
outermost surface may be less than 1.7.
[00 171
(9) In the chemical treatment steel sheet according to any one of (1) to (81, the
composite coated layer may contain 2 to 180 rng/m2 of Ni in terms of the amount of
metal Ni, and 0.2 to 8 mg/m2 of Sn in terms of the amount of metal Sn.
[00 1 81
(10) In the chemical treatment steel sheet according to any one of (1) to (9), a
surface of the chemical treatment layer may not be coated with a film or a coating.
[0019]
(1 1) According to another aspect of the invention, a method for producing a
chemical treatment steel sheet includes: a plating process of forming an Ni coated layer
that contains 2 to 200 mg/m2 ofNi in terms of an amount of metal Ni, and an Sn coated
layer that contains 0.1 to 10 g/m2 of Sn in terms of an amount of metal Sn on a surface
of a steel sheet; a reflow process of forming an Fe-Ni-Sn alloy layer 011 the steel sheet
and an island-shaped Sn coated layer on the Fc-Ni-Sn alloy layer by performing a
reflow treatment with respect to the steel sheet in which the Ni coated layer and the Sn
coated layer are formed; and a chemical trcatmcnt process of forming a cheniical
treatment laycr on the con~positec oated layer by performing an electrolytic treatment
in a chemical treatment liquid, which contains 10 pprn to less than 500 pprn of Zr ions,
10 to 20000 ppm of F ions, 10 to 3000 ppm of phosphate ions, and 100 to 30000 ppm
in a total amount of nitrate ions and sulfate ions and of which a temperature is set lo
equal to or higher than 5°C and lower than 90°C, under conditions of a current density
of 0.5 to 20 A/dm2 and an electrolytic treatment time of0.2 to 100 seconds, or by
performing an immersion treatment in the chemical treatment liquid for an itnmersion
time of 0.2 to 100 seconds.
[0020]
(12) In the method for producing a chemical treatment steel sheet according to
(1 I), the chemical treatment liquid may contain 100 ppm to less than 500 ppm of Zr
ions, 100 to 17000 ppm of F ions, 20 to 2000 ppm of phosphate ions, and 1000 to
20000 ppm in a total amount of nitrate ions and sulfate ions.
[Effects of the Invention]
[0021]
According to the aspects, it is possible to provide a chemical treatment steel
sheet having excellent yellowing resistance and corrosion resistance, and a method for
producing the chemical treatment steel sheet.
[Brief Description of the Drawings]
[0022]
FIG. 1A is a viela1 schematically showing an example of a chemical treatment
steel shezt in which a composite coated layer and a chemical treatment layer are
formed on a single surface of a steel sheet.
FIG. 1B is a vie\\ schematically showing an example of the chemical
treatment stccl sheet in which the compositc coated layer and the chemical treatment
layer are rormed on both surfaces of the steel sheet
FIG. 2 is a flow chart showing an example of a flow of a method of producing
the chemical treatment steel sheet.
FIG. 3 is a graph showing a result of Example 1
[Embodiments of the Invention]
[0023]
Hereinafter, a preferred embodiment of the invention will be described in
detail with reference to the accompanying drawings. Furthermore, in this
embodiment, the same reference numeral will be given to constituent elements having
the same configuration, and a redundant description thereof will be omitted.
[0024]

First, a configuration of a chemical treatment steel sheet according to an
embodiment of the invention will be described in detail with reference to FIG. 1A and
FIG. 1B. FIG. 1A and FIG. 1B schematically show a layer structure of the chemical
treatment steel sheet according to this embodiment when seen from a lateral side
[0025]
As shown in FIG. 1A and FIG. IB, a chemical treatment steel sheet 10
i according to this embodiment includes a steel sheet 103, a composite coated layer 106,
and a chemical treatment layer 107. Furthermore, the composite coated layer 106 and
the chemical treatment layer 107 may be formed on a single surface of the steel sheet
103 as shown in FIG. 1 A, or may be formed on both surfaces of the steel sheet 103 as
shown in FIG. 1B.
[0026]
[With Respect to Stecl Shect 1031
The steel sheet 103 is used as a base metal of the chemical treatment steel
sheet 10 according to this embodiment. With respect to the steel sheet 103 that 1s
used in this embodiment, a lmown steel sheet 103 that is used as a sted sheet for
containers may be used without particular limitation. In addition, with respect to a
method for producing the steel sheet 103 and a material thereof, a steel shcet 103,
which is produced through from a typical billet producing process to a known process
such as hot-rolling, pickling, cold-rolling, annealing, and temper rolling, may be used
without particular limitation.
It is preferable that the sheet thickness of the steel sheet 103 is 0.05 to 1 mm
in consideration of practicability and economic efficiency in a case of being used as a
steel sheet for containers.
[0027]
[With Respect to Composite Coated Layer 1061
The composite coated layer 106, which contains Ni and Sn, is formed on a
surface of the steel sheet 103. The composite coated layer 106 is a barrier-type
plating layer. Here, the barrier-type plating layer is a plating layer that suppresses
corrosion of the steel sheet 103 by forming a metal film of Sn on the surface of the
steel sheet 103 by using Sn that is a more electrochemically noble metal in comparison
to Fe that constitutes the steel sheet 103 that is the base metal in order for a corrosion
factor not to act on the steel sheet 103.
[0028]
Hereinafter, an example of the composite coated layer 106 according to this
embodiment will be described in detail with reference to FIG. 1A.
As shown in FIG. 1 A, the composite coated layer 106 includes ail Fe-Ni-Sn
alloy layer 105a that is formed on at least a single surfacc of thc stecl sheet 103, and an
island-shaped Sn coated laycr 105b that is formed on the Fe-Ni-Sn alloy layer 105a.
Although details will he described later, the Fe-Ni-Sn alloy layer 105a and the islandshaped
Sn coated layer 105b are formed by forming an Ni coated layer (not shown) as
an underlying layer on the surface of the steel sheet 103, additionally forming an Sn
coated layer (not shown) on the Ni coated layer (not shown), and performing a tin
melting treatment (reflow treatment).
That is, through the tin melting treatment, Fe of the steel sheet 103, Ni of the
Ni coated layer (not shown), and partial Sn of the Sn coated layer (not shown) are
alloyed to form the Fe-Ni-Sn alloy layer 105a. In addition, the residual Sn coated
layer (not shown) becomes an island shape, and thus the island-shaped Sn coated layer
105b is formed.
[0029]
The Ni coated layer (not shown), which is provided to form the Fe-Ni-Sn
alloy layer 105a and contains Ni or an Fe-Ni alloy, is formed to secure corrosion
resistance. Ni is highly corrosion-resistant metal. Accordingly, when Ni is plated
on the surface of the steel sheet 103, it is possible to improve the corrosion ~csistance
of the chemical treatment steel sheet 10.
[0030]
An effect of improving the corrosion resistance of the chemical treatment
steel sheet 10 with Ni is determined in accordance with the amount of Ni contained in
the composite coated layer 106. When the amount of Ni in the composite coated
layer 106 is 2 mg/m2 or more per single surfacc in terms of the amount of metal Ni, the
effect of improving the corrosion resistance with Ni is exhibited.
On the other hand, the greater the amount of Ni in the conlposite coated layer
106 is, the fi~rthctrh e efSect oS improving the corrosion resislance increases.
EIowcver, when the amount of Ni in the composite coated layer 106 is grcater than 200
mg/m2 pcr single surface in terms of the amount of metal Ni, the effect of improving
the corrosion resistance with Ni is saturated. In addition, Ni is an expensive metal.
Accordingly, when the amount of Ni in the composite coated layer 106 is grcater than
200 mdm2 per single surface in terms of the amount of metal Ni, this case is not
preferable in an economic aspect.
Accordingly, the amount of Ni in the composite coated layer 106 is set to 2
mg/m2 to 200 mg/m2 per single surface in terms of the amount of metal Ni. Morp
preferably, the amount of Ni in the composite coated layer 106 is 2 mg/m2 to 180
mg/m2 per single surface in terms of the amount of metal Ni. When the composite
coated layer 106 contains 2 mg/m2 or more of Ni per single snrface in terms of the
amount of metal Ni, the effect of improving corrosion resistance with Ni is more
effectively exhibited. In addition, when the amount of Ni in the composite coated
layer 106 is set to 180 mg/m2 or less per single surface in terms of the amount of Ni, it
is possible to further reduce the production cost.
[0031]
After the above-described Ni coated layer (not shown) is formed, the Sn
coated layer (not shown) is formed. Furthermore, the Sn coated layer (not shown) in
this embodiment may be configured only by Sn, or may contains an impurity or a
slight amount of element in addition to Sn.
[0032]
The Sn coated layer (not shown) is formed to secure the corrosion resistance
and weldability of the chemical treatment steel sheet 10. Sn itself has high corrosion
resistance, and an Sn alloy formed through the tm melting treatment also has excellent
corrosion resistance and weldability.
After forming the Sn coated layer (not shown), the tin mclting treatment is
percormed. According to this, the Fe-Ni-Sn alloy layer 105a is formed on the steel
sheet 103, and the island-shaped Sn coated layer 105b is formed on the Fe-Ni-Sn alloy
layer 105a.
[0033]
In the island-shaped Sn coated layer 105b, Sn cxists in an island shape, and on
a lower side thereof, the Fe-Ni-Sn alloy layer 105a, which is a lower layer, is exposed.
Film adhesion and coating adhesion of the chemical treatment steel sheet 10 are
secured due to the island-shaped Sn coated layer 105b.
In a heat treatment after film lamination and coating application, the chemical
treatment steel sheet 10 may be heated to a temperature eqdal to or higher than the
melting point (232°C) of Sn. In a case of the entirety of the surface of the Fe-Ni-Sn
alloy layer 105a is coated with Sn differently from this embodiment, Sn is melted or
oxidized due to the above-described heat treatment, and thus the film adhesion and the
coating adhesion of the chemical treatment steel sheet 10 may not be secured.
Accordingly, this case is not preferable.
[0034]
The composite coated layer 106 according to this embodiment contains 0.1 to
10 g/m2 of Sn per single surface in terms of the amount of metal Sn.
Sn has excellent workability, weldability, and corrosion resistance. When
the tin melting treatment is performed after Sn plating, it is possible to further improve
the corrosion resistance of the chemical treatment steel sheet 10, and it is possible to
attain more preferred surface exterior appearance (mirror surface exterior appearance)
of thc chemical treatment steel sheet .I 0. The comnposite coated layer 106 is required
to contam 0.1 g/m2 of Sn pel ~inglesu rface in terms of thc amount of mctal Sn so as to
exhibit the above-described effect.
[0035]
In addition, as the amount of Sn contained in the composite coated layer 106
increases, the workability, the weldability, and the corrosion resistance of the chemical
treatment steel sheet 10 are improved. However, when the amount of Sn contained is
greater than 10 g/m2 per single surface in terms of the amount of metal Sn, the abovedescribed
effect with Sn becomes saturated. In addition, when the amount of Sn
contained is greater than 10 g/n~p2e r single surface in terms of the amount of metal Sn,
this is not preferable from an economical aspect. From the above-described reason,
the amount of Sn contained in the composite coated layer 106 is set to 10 g/m2 or less
per single surface in terms ofthe amount of metal Sn.
More preferably, the amount of Sn contained in the composite coated layer
106 is 0.2 g/m2 to 8 g/m2 per single surface in terms of the amount of metal Sn.
When containing 0.2 g/m2 or more of Sn per single surface in terms of the amount of
metal Sn, the composite coated layer 106 can more reliably exhibit the abovedescribed
effect with Sn. In addition, when the composite coated layer 106 contains 8
g/m2 or less of Sn per single surface in terms of the amount of metal Sn, it is possible
to further reduce the production cost.
100361
In the composite coated layer 106, the total of the amount of Ni contained in
terms of the amount of metal Ni and the amount of Sn in terms of the amount of metal
Sn is 50% by mass or more on the basis of the mass of the composite coated layer 106.
Preferably, in the composite coated layer 106, the total ofthe amount of Ni contained
in terms of the amount of metal Ni and the amount of Sn contained in terms of the
amount of metal Sn is 70% by mass or morc on the basis of the mass of the composite
coated layer 106.
[0037]
The composite coated layer 106 may contain 1 to 2000 mg/m2 of Fe per single
surface in terms of the amount of metal Fe in addition to Ni and Sn as described above.
In addition, the composite coated layer 106 may contain unavoidable impurities which
are mixed-in in a production process and the like.
[0038]
In a case of using the steel sheet 103, on which the composite coated layer
106 is formed, as a steel sheet for containers which store acidic contents such as acidic
fruits, a coating treatment is not performed on a surface that comes into contact with
the acidic contents. When the composite coated layer 106 and the acidic contents
come into direct contact with each other, Sn in the composite coated layer 106 is eluted,
and is likely to react with 0 2 contained in the contents. According to this, oxidation
of the acidic contents is prevented.
However, SnO, which is generated through a reaction between Sn and 02, is a
yellow compound. According to this, the surface of the steel sheet 103, on which the
composite coated layer 106 is formed, is discolored to yellow (yellowing) according to
the formation of SnO. When the yellowing occurs, the contents may be
misunderstood as decaying, and thus the yellowing is not preferable. According to
this, the present inventors have thought of a configuration in which the chemical
treatment layer 107 is formed on the composite coatcd layer 106 so as to suppress the
yellowing ofthe surface of the steel sheet 103 on which the composite coated layer
106 is formed.
[0039]
The prcscnt inventors have obtained the following finding. In a case where
the chcmical treatment layer 107 that contains Zr is formed on the composite coatcd
layer 106, the adhered amount of the chemical treatment layer 107 becomes equal to or
greatcr than a predetermined amount, the chemical treatment layer 107 is gradually
discolored yellow.
Accordingly, the present inventors have madc an additional investigation, and
have found a chemical treatment steel sheet 10 in which the yellowing of the chemical
treatment layer 107 that contains Zr is suppressed, and satisfactory external appearance
is maintained. That is, in the invention, the chemical treatment layer 107, of which an
adhered amount is in a specific range and which contains Zr, is formed on the
composite coated layer 106.
[0040]
[With Respect to Chemical Treatment Layer 1071
As shown in FIG. 1A and FIG. lB, the chemical treatment layer 107 is
formed on the composite coated layer 106. The chemical treatment layer 107 is a
composite film layer that mainly contains a Zr compound, and contains a 0.01 to 0.1
mg/mz of Zr compounds per single surface in terms of the amount of metal Lr and 0.01
to 5 mg/m2 of phosphate compounds per single surface in terms of the amount of P.
[0041]
In a case where two films of a Zr film that contains the Zr compounds and a
phosphate film that contains the phosphate compounds are formed on the composite
coated layer 106 in a state in which the two films overlap each other, a certain degree
of effect is obtained on corrosion resistance or adhesion, but the effect is not sufficient
in practical use. However. as is the case with this embodiment, when the Zr
compounds and the phosphate compounds exist in the chemical treatment layer 107 in
a statc of being partially niixcd, it is possible to attain more excellent corrosion
resistance and adhesion in comparison to the case where the two films are formed to
overlap each other as described above.
The Zr compound, which is contained in the chemical treatment layer 107
according to this embodiment, has a function of improving corrosion resistance,
adhesion, and working adhesion. Examples of the Zr compounds according to this
embodiment include Zr oxide, Zr phosphate, Zr hydroxide, Zr fluoride, and the like,
and the chemical treatment layer 107 contains a plurality of the Zr compounds. A
preferred combination of the Zr compounds is a combination of the Zr oxide, the Zr
phosphate, and the Zr fluoride.
[0043]
In a case where the amount ofihe Zr compounds contained in the chemical
treatment layer 107 is 0.01 mg/m2 or more per single surface in terms of the amount of
metal Zr, corrosion resistance, adhesion of a coating and the like, and yellowing
resistance, which are suitable in practical use, are secured.
On ihe other hand, as the amount of the Zr compounds contained increases,
corrosion resistance, adhesion, and adhesion of a coating and the like are improved.
However, when the amount of the Zr compounds contained is greater than 0.1 mg/m2
per single surface in terms of the amount of metal Zr, yellowing characteristics of the
chemical treatment layer 107 in accordance with a variation with the passage of time
bccome significant. Accordingly, the chemical treatment layer 107 according to this
embodiment contains 0.01 mg/m2 to 0.1 mg/m2 of Zr compounds per single surface in
terms the amount of metal Zr.
[0044]
The upper limit of the amount of Zr compounds contained is prererably 0.08
mg/m2 or lcss per single surface in tcrms of thc amount of metal Zr, and more
prcferably less than 0.06 mg/m2 per single surface in tcrms of the amount of metal Zr.
In addition, the lower limit of the amount ofthe Zr compounds contained is
preferably 0.02 mg/m2 or more per single surface in terms of the amount of metal Zr.
When the amount of the Zr compounds contained is set to the above-described
range, it is possible to attain more excellent corrosion resistance, adhesion, adhesion of
a coating and the like, and yellowing resistance.
[0045]
The chemical treatment layer 107 further contains one or more kinds of
phosphate compounds in addition to the above-described Zr compound.
100461
The phosphate compounds according to this embodiment has a function of
improving corrosion resistance, adhesion, and working adhesion. Examples of the
phosphate compounds according to this embodiment include Fe phosphate, Sn
phosphate, Zr phosphate, and the like which are formed through a reaction between
phosphate ions and cotnpounds which are included in the steel sheet 103, thc
composite coated layer 106, and the chemical treatment layer 107. The chemical
treatment layer 107 may contain one kind or two or more kinds of the phosphate
compounds.
[0047]
The greater the amount of the phosphate compounds contained in the
chemical treatment layer 107 is, the further corrosion resistance, adhesion, and
working adhesion of the chemical treatment steel sheet 10 are impl-oved. Specifically,
in a case where the amount of the phosphate compounds contained in the chcinical
treatment layer 107 is greater than 0.01 mg/m2 per single surface in tcrms of thc
amount of P, corrosion resistance, adhesion, adhcsion oC worlting and the lilte, and
yellowing resistance, which are suitable in practical usc, arc sccured.
On the other hand, as the amount of the phosphate compounds contained
increases, corrosion resistance, adhesion, and working adhesion are also improved.
However, when the amount of the phosphate compounds contained is greater than 5
mg/rn2 per single surface in terms of the amount of P, the yellowing characteristics of
the chemical treatment layer 107 in accordance with a variation with the passage of
time become significant. Accordingly, the chemical txeatment layer 107 according to
this embodiment contains 0.01 mg/m2 to 5 mg/m2 of phosphate compounds per single
surface in terms the amount of P.
[0048]
The upper limit of the amount of phosphate compounds contained is
preferably 4 mg/m2 or less per single surface in tenns of the amount of P, and more
preferably less than 1 mg/m2 per single surface in terms of the amount of P.
In addition, the lower limit of the amount of the phosphate compounds
contained is preferably 0.03 mg/m2 or more per single surface in terms of the amount
of P. When the amount of the phosphate compounds contained is set to the abovedescribed
range, it is possible to attain more excellent corrosion resistance, adhesion,
working adhesion, and yellowing resistance.
[0049]
Furthermore, the chemical treatment layer 107 may further contain
: unavoidable impurities which are mixed-in in a production process and the like in
addition to the Zr compounds and the phosphate compound. In addition, in a case
where tlie chemical treatment layer 107 contains Cr, the upper limit of the amount of
Cr containcd is 2 mg/m2.
LO0501
The chemical treatment steel sheet 10 according to this cmboditnent includes
the above-described chemical treatment layer 107, and thus exhibits excellent
yellowing resistance. For example, when the chemical treatment steel sheet 10 is
used for storage for 4 weeks in an environment of a temperature of 40°C and a
humidity of 80%, a value (hereinafter, referred to as "AYI value"), which is obtained
by extracting a YI value of the chemical treatment steel sheet before storage from a YI
value (yellowness index) of the chemical treatment steel sheet after storage, is 1.7 or
less. That is, the AYI value in a case of storage for 4 weeks in an environment of a
temperature of 40°C and a humidity of 80% is 1.7 or less.
[005l]
The YI value is a value obtained by digitizing tristimulus values (perceiving
sensitivity of red, blue, and yellow which are sensed by eyes of human beings) of a
color. As the YI value shows a value that is higher on a positive side, yellow
becomes dark. As the YI value shows a value that is higher on a negative side, bluish
white becomes dark. Accordingly, after storage in the above-described environment,
in a case where the AYI value is a positive value, this case represents an increase in the
yellowness index, and in a case where the AYI value is a negative value, this case
represents a decrease in the yellowness index and an increase in the degree of bluishwhiteness.
!
Furthermore, the YI value is calculated by substituting tristimulus values X, Y,
and Z obtained by using a white measurement m-ter into the following Expression (1).
[0052]
YI value = IOO(1.28X-I .ObZ)+Y ...( I)
[0053]
Herc, in a case where the AYI value is greater than 1.7, it is possible to
perceive that an object turns yellow. On the other hand, in a casc thc chemical
treatment steel sheet 10 according to this embodiment is stored for 4 weeks in an
environment of a temperature of 40°C and a humidity of 80%, the AYI value before
and after storage is 1.7 or less. That is, in a case of comparing thc yellowness index
of the chemical treatment steel sheet 10 after storage for 4 weeks in an environment of
a temperature of 40°C and a humidity of 80%, and the yellowness index of the
chemical treatment steel sheet 10 before storage, it is difficult to perceive an increase
(yellowing) in the yellowness index of the chemical treatment steel sheet 10.
According to this, in the chemical treatment steel sheet 10 according to this
embodiment, the yellowness index in the exterior appearance does not vary with the
passage of time, and satisfactory exterior appearance can be maintained for a long
period of time.
Furthermore, in this embodiment, the performance of maintaining the
satisfactory exterior appearance for a long period of time is referred to as "yellowing
resistance".
[0054]

As described above, the chemical treatment steel sheet 10 includes the
composite coated layer 106 on the steel sheet 103, and the chemical treatment layer
107 on the composite coated layer 106. That is, in the chemical treatment steel sheet
10, the steel sheet 103 and the composite c,oated layer 106 are in contact with each
other, and another layer is not provided between the steel shcet 103 and the composite
coated layer 106. Similarly, 111 the chemical treatment steel sheet 10, the coiuposite
coated layer 106 and the chemical treatment layer 107 are in contact with each other,
and another layer is not provided between the con~positec oated layer 106 and the
chemical treatment layer 107.
[0055]

Here, for example, the amount of metal Ni and the amount of metal Sn in the
composite coated layer 106 can be measured by using a fluorescent X-ray method. In
this case, a calibration curve with respect to the amount of metal Ni or the amount of
metal Sn is created in advance by using a known sample for measurement of the
amount of metal Ni and the amount of metal Sn, and the amount of metal Ni or the
amount of metal Sn is relatively specified by using the calibration curve that is created.
[0056]
For example, the amount of metal Zr and the amount of P in the chemical
treatment layer 107 can be measured by quantitative analysis such as fluorescent X-ray
analysis. In addition, it is possible to specify existence of a compound in the
chemical treatment layer 107 by performing analysis with X-ray photoelectron
spectroscopy (XPS).
[0057]
Furthermore, the method of measuring each component is not limited to the
above-described method, and a lcnown measurement method can be applied thereto.
[0058]

Measurement of the YI value (yellowness index) may be performed by using
a spectrophotometer based on JlS 2-8722 condition c With regard to a measurement
type, the measurement can be performed through SCI (including regular reflection
light) measurement that is less susceptible to an effect by a surface properly. I11
addition, with rcgard to measurement conditions, it is important to perform thc
measurement under constant conditions such as a constant light source, constant
humidity, and a constant temperature.
[0059]
Furthermore, in measurement of the YI value, for example, it is preferable to
measure YI values at a plurality of measurement points such as arbitrary 20 points per
1 m2, and to use an average value thereof. Here, the measurement points represent a
plurality of arbitrary measurement points on a single surface at the outermost surface
portion of the chemical treatment layer 107. In addition, it is preferable that the
measurement points are set to points which are spaced away from each other by at least
10 cm. Specifically, in a case of a large sheet having dimensions of 1 mxl m, it is
preferable measurement points are sampled, and points spaced away from each other
by 10 cm or more are sampled to perform measurement.
[0060]

Next, a method of producing the chemical treatment steel sheet 10 according
to this embodiment will be described in detail with reference to FIG. 2. FIG. 2 is a
flowchart showing an example of a flow of the method of producing the chemical
treatment steel sheet according to this embodiment.
[0061]
[Pre-Treatment Process]
In the method of producing the chemical treatment steel sheet 10 according to
this embodiment, first, a known preliminary treatment is performed with respect to the
steel shcet 103 as necessary (step S101).
[0062]
[Plating Process]
Thcn, the composite coated layer 106 is formed on a surface of the steel sheet
103 (step S103). When forming the composite coated layer 106, an Ni coated layer
(not shown) which is consisted of Ni or an Fe-Ni alloy is formed on the surface of the
steel sheet 103, and an Sn coated layer (not shown) is additionally formed on the Ni
coated layer (not shown).
LO0631
As a method of forming the Ni coated layer (not shown) which is consisted of
from Ni or an Fe-Ni alloy, a typical electric plating method (for example, a cathode
electrolytic method) can be used.
A method of forming the Sn coated layer (not shown) is also not particularly
limited. For example, a known electric plating method, a method of immersing the
steel sheet 103 in molten Sn for plating, and the like can be used.
[0064]
In a case of forming the Ni coated layer (not shown) by using a diffusion
plating method, after carrying out Ni plating on the surface orthe steel sheet 103, and a
diffusion treatment of forming a diffusion layer is performed in an annealing furnace.
A nitriding treatment may be performed before and after the diffusion treatment, or
simultaneously with the diffusion treatment. Even when performing the nitriding
treatment, an effect with Ni in the Ni coated layer (not shown) in this embodiment, and
an effect by the nitriding treatment can be exhibited without interference from each
other.
[0065]
[Tin Melting Treatment (Retlow Treatment) P~ocess]
Aftcr forming the Sn coated layer (not shown), a tin melting treatment (reflow
treatment) is pcrformed (step S104). Since the tin melting treatment is performed,
molten Sn, Fe in the stccl shcct 103, and Ni in thc Ni coated layer (not shown) are
alloyed, thereby forming the Fe-Ni-Sn alloy layer 105a and the island-shaped Sn
coated layer 105b that is formed in an island shape and is formed from Sn. Thc
island-shaped Sn coated layer 105b can be formed by appropriately controlling the tin
melting treatment.
[0066]
[Chemical Treatment Process]
Then, the chemical treatmcnt layer 107 is formed on the composite coated
layer 106 through a cathode electrolytic treatment or an immersion treatment (step
S105).
The chemical treatment layer 107 is formed through a cathode electrolytic
treatment or an immersion treatment, but a chemical treatment liquid is used in any
case. The chemical treatment liquid according to this embodiment contains 10 pprn
to less than 500 pprn of Zr ions, 10 pprn to 20000 pprn of F ions, 10 pprn to 3000 pprn
of phosphate ions, and 100 pprn to 30000 pprn in a total amount of nitrate ions and
sulfate ions.
In addition, the nitrate ions and the sulfate ions may be contained in the
chemical treatment liquid in a total amount of 100 pprn to 30000 ppm. Both of the
nitrate ions and the sulfate ions may be contained in the chemical treatment liquid, or
only any one of the nitrate ions and the sulfate ions may be contained in the chemical
treatment liquid.
100671
It is preferable that the chemical treatment liqu~dc ontains 100 ppm to less
than 500 pp~uo T%r ions, 100 ppm to 17000 ppm of F ions, 20 ppm to 2000 ppn? of
phosphate ions, and 1000 ppm to 20000 ppm in a total amount of nitrate ions and
sulfate ions.
[0068]
When the concentration of the Zr ions is set to 100 ppm or greater, it is
possible to more reliably prevent a decrease in an adhered amount of Zr. 11s addition,
when the concentration ofthe F ions is set to 100 pprn or greater, it is possible to more
reliably prevent white turbidity of the chemical treatment layer 107 in accordance with
precipitation of a phosphate.
Similarly, when the concentration of the phosphate ions is set to 20 ppm or
greater, it is possible to more reliably prevent white turbidity of the chemical treatment
layer 107 in accordance with precipitation of the phosphate.
[0069]
When the total concentration of the nitrate ions and the sulfate ions is set to
1000 pprn or greater, it is possible to more reliably prevent a decrease in adhesion
efficiency of the chemical treatment layer 107.
In a case where the total concentration of the nitrate ions and the sulfate ions
is less than 1000 ppm, the adhesion efficiency of the Zr ions is low, and thus the
amount of Zr contained in the chemical treatment layer 107 decreases. Accordingly,
this case is not preferable. On the other hand, when the total concentration of the
nitrate ion.; and the sulfate ions is greater than 20000 ppm, the adhesion efficiency of
the Zr ions is high, and thus the amount of Zr contained in the chemical treatment layer
107 excessixely increases. Accordingly, this case is not preferable.
[0070]
Furthermore, when the upper limits of the rcspcctive components in thc
chemical tl.catinent liquid are set to the above-dcscribed values, it is possible to more
reliably reduce the production cost of the chemical treatment layer 107.
[0071]
It is preferable that pH of the chemical treatment liquid is in a tange of 3.1 to
3.7, and more preferably approximately 3.5. Nitric acid, ammonia, and the like may
be added to the chemical treatment liquid for adjustment of pH thereof as necessary.
Furthermore, even in any of the chemical treatment liquid that is used in the
electrolytic treatment and the chemical treatment liquid that is used in the immersion
treatment, it is preferable to satisfy the conditions of pH of the chemical treatment
liquid.
It is preferable that a temperature of the chemical treatment liquid is equal to
or higher than 5°C and lower than 90°C. In a case where the temperature of the
chemical treatment liquid is lower than 5"C, formation efficiency of the chemical
treatment layer 107 is poor, and is not economically efficient. Accordingly, this case
is not preferable. Furthermore, in a case where the temperature of the chemical
treatment liquid is 90°C or highcr, a structure of the chemical treatment layer 107 that
is formed is not uniform, and a defect such as cracking and a micro-crack occurs.
The defect becomes the origin of corrosion and the like, and thus this case is not
preferable. In addition, even in any of the chemical treatment liquid that is used in
the electrolytic treatment and the chemical treatment liquid that is used in the
immersion treatment, it is preferable to satisfy the temperature conditions of the
chemical treatment liquid.
: Furthermore, when the temperature of the chemical treatment liquid is set to
be higher than a surface temperature of the steel sheet 103 on which the composite
coated layer 106 is formed, reactivity of the chemical treatment liquid increases at an
interface, and thus adhesion cfficicncy of the chemical treatment layer 107 is iinprovcd.
According to this, it is preferable that the temperature of the chemical treatment liquid
is higher than the surface temperature of the steel sheet 103 on which thc compositc
coated layer 106 is ihrmed.
LO0721
[Case of Forming Chemical Treatment Layer 107 by Electrolytic Treatment]
It is preferable that a current density in the electrolytic treatment is 0.5 A/dm2
to 20 A/dm2. In a casc where the current density is less than 0.5 A/dm2, thc adhered
amount of the chemical treatment layer 107 decreases, and an electrolytic treatment
time may be longer, and thus this case is not preferable. In addition, in a case where
the cunent density is greater than 20 A/dm2, the adhered amount of the chemical
treatment layer 107 becomes excessive, and in the chemical treatment layer 107 that is
formed, a portion that is not sufficiently adhered may be washed out (peeled offl in a
washing process through water washing after the electrolytic treatment. Accordingly,
this case is not preferable.
It is preferable that the electrolytic treatment time is 0.05 seconds to 10
seconds. In a case where the electrolytic treatment time is shorter than 0.05 seconds,
the adhered amount of the chemical treatment layer 107 decreases, and desired
performance is not obtained. Accordingly, this case is not preferable. On the other
hand, in a case where the electrolytic treatment time is longer than 10 seconds, the
adhered amount of the chemical treatment layer 107 becomes excessive, and in the
chemical treatment layer 107 that is formed, a portion that is not sufficiently adhered
may be washed out (peeled off) in a washing process through water washing afier the
electrolytic treatment. Accordingly, this case is not preferable.
[0073]
[Case of Forming Chemical Treatment Laycr 107 by Immersion Trealment]
The chemical treatment layer 107 according to this cmbodinient may be
formed through an immersion treatment using the chemical treatment liquid. In a
case of forming the chemical treatment layer 107 through the immersion treatment, the
steel sheet 103 including the composite coated layer 106 is immersed in the abovedescribed
chemical treatment liquid for 0.2 to 100 seconds.
In a case where an immersion time is shorter than 0.2 seconds, the adhered
amount of the chemical treatment layer 107 is not sufficient, and thus this case is not
preferable. On the other hand, in a case where the immersion time is longer than 100
seconds, the adhered amount of the chemical treatment layer 107 becomes excessive,
and in the chemical treatment layer 107, a portion that is not sufficiently adhered may
be washed out (peeled of0 in a washing process through water washing after the
electrolytic treatment. Accordingly, this case is not preferable.
[0074]
Furthermore, in formation of the chemical treatment layer according to this
embodiment, tannic acid may be further added to the chemical treatment liquid.
When the tannic acid is added to the chemical treatment liquid, the tannic acid reacts
with Fe in the steel sheet 103, and a film of tannic acid Fe is formed on the surface of
the steel sheet 103. The film of the tannic acid Fe improves rust resistance and
adhesion, and is preferable.
[0075]
1 As a solvent of the chemical treatment liquid, for example, deionized water,
I
distilled water, and the like can be used. Electric conductivity of the solvent of the
chemical treatment liquid is preferably 10 yS/cm or less, more preferably 5 pS/cm or
less, and still more preferably 3 pS1cin or less. However, the solvent of the chcinical
treatment liquid is not limited thereto, and can be appropriately selcctcd in accordance
with a material to be dissolvcd, a formatioii method, formation conditions of the
chemical trcatnienl layer 107, and the like. However, it is preferable to use deionized
water or distilled water from aspects of industrial productivity based on stability in an
adhered amount of each component, cost, and environment.
[0076]
As a supply source of Zr, for example, a Zr complex such as HzZrF6 can be
used. Zr in the Zr complex exists as zr4+ in the chemical treatment liquid though a
hydrolysis reaction in accordance with an increase in pH at a cathode electrode
interface. The Zr ions perform dehydration and condensation reaction with a
hydroxyl group (-OH) that exists on a metal surface in the chemical treatment liquid to
form a compound such as ZrO2 and Zr3(PO4)4.
[0077]
[Post-Treatment Process]
Then, a known post-treatment is performed as necessary with respect to the
steel sheet 103 on which the composite coated layer 106 and the chemical treatment
layer 107 are formed (step S107).
[0078]
Through the treatment performed in this flow, the chemical treatment steel
sheet 10 according to this embodiment is produced.
Examples
[0079]
Hereinafter, the chemical treatment steel sheet and the method of producing
the chemical treatment steel sheet according to this embodiment of the invention will
be described in detail with rcfercucc to Examples. In addition, the following
Examples arc examples orthe chemical trcatmcnt steel sheet and the method of
producing the chemical treatment stcel sheet according to thc embodimcnt of the
invention, and the chemical treatment steel sheet and the method of producing the
chemical treatment steel sheet according to the embodimcnt of the invention are not
limited to the following examples.
[OOSO]
(Example 1)
Hereinafter, Ilrst, verification was made as to how the YI value varies before
and after storage for 4 weeks in an environment of a temperature of 40°C and a
humidity of 80% while varying the amount of Zr contained in thc chemical treatment
layer. Furthermore, the amount of Zr contained and the YI value were measured by
the above-described method.
[008l]
In Example 1, a steel sheet, which is typically used as a steel sheet for
containers, was used as a base metal, and the composite coated layer was formed on
the steel sheet. The amount of Ni contained in the composite coated layer was set to
120 mg/m2 per single surface in terms of the amount of metal Ni, and the amount of Sn
contained was set to 2.8 g/m2 per single surface in terms of the amount of metal Sn.
Furthermore, a plurality of samples including chemical treatment layers, in which the
amounts of Zr compounds contained were different from each other, were produced by
changing the concentration of Zr ions in the chemical treatment liquid. Here, the
amount of phosphate compounds contained in each sample was set to 3.0 mglm2 per
single surface in terms of the amount of P.
[0082]
Obtained Results are shown in FIG. 3.
In FIG. 3, the horizontal axis represents the amount oSZr compounds (the
amount of metal Zr) contained in the chemical treatment layer, and the vertical axis
represents a value (AYI value) obtained by subtracting a YT value before storage from
a YT value aftcr storage. As is clear from FIG. 3, in a case where the amount of Zr
contained was 0.0 1 to 0.10 mgim2 per single surface in terms of the amount of metal Zr,
the AYI value was 1.7 or less, and an increase in the yellowness index in accordance
with storage with the passage of time was not recognized.
From the results, when the amount of Zr compounds contained in the
chemical treatment layer was set to the predetermined range, it could be seen that the
produced chemical treatment steel sheet had excellent yellowing resistance.
[0083]
(Example 2)
Next, a steel sheet, which is typically used as a steel shect for containers, was
used as a base metal, and a chemical treatment layer including a composite coated
layer having the amount of metal Sn and the amount of metal Ni as shown in the
following Table 1, and a chemical treatment layer having the amount of metal Zr and
the amount of P as shown in the following Table 1 were respectively formed by the
above-described method.
With respect to respective samples which were produced as described above,
the AYI value before and aftcr storage for 4 weeks in an environment of a temperature
of 40°C and a humidity of 80% was measured.
The amount of each component contained, and the AYI value were measwed
by the above-described method.

As a corrosion resistance test liquid, 3% acetic acid was uqed. The chemical
treatment steel sheet as the sample was cut out to a dimension oS $35 mm. The cdout
sample was placed on an inlet oSa heat resistant bottlc into which thc corrosion
resistance test liquid was put, and was fixed thereto. After performing a heat
treatment at 121°C for 60 minutes, a contact portion between the sample and the
corrosion resistance test liquid was observed to evaluate the degree of corrosion of the
sample. Specifically, the following ten-step evaluation was performed by using an
area of a portion that is not corroded with respect to the total area of the contact portion
between the sample and the corrosion resistance test liquid. Furthermore, a score is 5
points or greater, the steel sheet can be used as a steel sheet for container.
[0085]
10 points: 100% to 90%
9 points: less than 90% and equal to or greater than 80%
8 points: less than 80% and equal to or greater than 70%
7 points: less than 70% and equal to or greater than 60%
6 points: less than 60% and equal to or greater than 50%
5 points: less Lhan 50% and equal to or greater than,40%
4 points: less than 40% and equal to or greater than 30%
3 points: less than 30% and equal to or greater than 20%
2 points: less than 20% and equal to or greater than 10%
1 point: less than 10% and equal to or greater than 0%
[0086]
In a corrosion resistance evaluation item, 10 points to 9 points are described
as "Very Good", 8 points to 5 points arc described as "Good", aud 4 points or l e ~asr e
described as "Not Good".
[0087]
[Table 11

[OOSX]
As shown in Table 1, in Exaniplcs A1 to Al9, the colrosion resistance and the
yellowing resistance were excellent. On the other hand, in Comparative Examples a1
to a6, any one of the corrosion resistance and the yellowing resistance was poor.
[OO89]
(Example 3)
A steel sheet, which is typically used as a steel shcct for containers, was used
as a base metal, and a chemical treatment was performed on a composite coated layer
having the amount of metal Sn and the amount of mctd Ni as shown in the following
Table 2 under conditions shown in the following Table 3 to form a chemical treatmeut
layer. With respect to each sample, the corrosion resistance and the yellowing
resistance were measured by the same method as described above.
Results are shown in Table 4.
[O09O]
[Table 21
Composite coated layer
Amount
Amount of
bol
of metal
metal Sn
Examples
Comparati
ve
Examples
LOOSl]
[Table 31

[Table 41
Chemical treatment layel.
Sym
bOl
8 1
Characteristic evaluatio~~
I
I
Examples
B4
85
AYI value
0.3
Am( ;ion
82 1 0.01
mew, Ail
(mglm2)
0.03
1.7 / Very Good 1 0.4
0.03 1 0.6 Very Good 0.4
813
814
815
B16
B21 I 0.01 3.6 I Very Good / 0.8 1 . -
0.02 1 1.8
B17
818
B19
B20
(mglm2)
0.1
Very Good
0.01 Very Good
0.02
0.02
0.01
0.01
~ c ~ s r a n c e
Very Good
B3
0.5
0.1 0.1
0.03
0.04
0.01
0.03
022
Vely Good
1.9
3.3
3.0
3.2
- ~-~~~~
823
B24
B25
826
0.01 0.2
0.4
2.9
1 .O
0.7
0.04
0.9
Very Good
Very Good
Very Good
Verv Good
3.4 1 very Good / 1.1
--
0.03
0.03
0.02
0.01
B27
B28
B29
B30
bl I 0.006
0.6
0.9
0.7
0.7
Very Good
Very Good
Very Good
Very Good
1.5
2.0
1.8
3.3
0.04
0.02
0.03
0.02
1.6 / Vely Good I 5.2
Comparativ
e Examples
0.4
1 .0
0.3
0.4
0.1
2.0
0.7
3.6
Very Good
Very Good
Very Good
Very Good
b2 I 0.008
b3
b4
b5
b6
Very Good
Very Good
Very Good
Verv Good
0.7
0.6
0.7
0.9
2.5 I very ~ o o d / -6.7
0.4
0.7
0.3
0.8
0.02
0.005
0.004
0.003
o.002
4.3
2.2
0.7
Very Good
Very Good
Very Good
Verv Good
-5.2
5.5
-4.7
5.2
LO0931
As shown in Table 4, in Examples B1 to B30, ihe corrosion resistance and the
yellowing resistance were excellent. On the other hand, in Comparative Examples bl
to b9, the corrosion resistance was exccllent, but the yellowing resistance was poor.
[0094]
Hereinbefore, preferred embodiment of the invention has been described in
detail with reference to the accompanying drawings, but the invention is not limited to
the example. It should be understood by those skilled in the art that various
modification examples and variations may be made in a scope of the technical sprit
described in claims, and these also pertain to the technical scope of the invention.
[Industrial Applicability]
[0095]
According to the embodiment, it is possible to provide a chemical treatment
steel sheet having excellent yellowing resistance and corrosion resistance, and a
method for producing the chemical treatment steel sheet.
[Brief Description of the Reference Symbols]
[0096]
10: CHEMICAL TREATMENT STEEL SHEET
103: STEEL SHEET
105a: Fe-Ni-Sn ALLOY LAYER
105b: ISLAND-SI-IAPED Sn COATED LAYER
106: COMPOSITE COATED LAYER
107. CHEMICAL TREATMENT LAYER
--
b7
bX
b9
0.002
0.004
0.002
2.5 -
1.9
2.0
Very Good
Very Good
Very Good
5.4
7.0
5.4
[Document Type] C1,AIMS
What is claimed is:
1. A chemical treatment stecl sheet comprising:
a steel sheet;
a composite coated layer which is formed on at least one surface of the steel
sheet, and contains 2 to 200 mg/m2 of Ni in terms of an amount of metal Ni and 0.1 to
10 g/m2 of Sn in terms of an amount of metal Sn, and in which an island-shaped Sn
coated layer is formed on a Fe-Ni-Sn alloy layer; and
a chemical treatment layer that is formed on the composite coated layer, and
contains 0.01 to 0.1 mg/m2 of Zr compounds in terms of an amount of metal 7r and
0.01 to 5 mg/m2 of phosphate compounds in terms of an amount of P.
2. The chemical treatment stcel sheet according to Claim 1,
wherein the chemical treatment layer contains 0.08 mg/m2 or less of the Zr
compounds in terms of the amount of metal Zr.
3. The chemical treatment steel sheet according to Claim 2,
wherein the chemical treatment layer contains 0.06 mg/m2 or less ofthe Zr
compounds in terms of the amount of metal Zr.
4. The chemical treatment steel sheet according to any one of Claims 1 to 3,
wherein the chemical treatment layer contains 0.02 mg/m2 or greater of the Zr
compounds in terms of the amount of metal Zr.
5. The chemical treatmeni steel sheet according to any one of Claims 1 to 4,
whcrein thc chemical treatment layer contains 4 mg/ni2 or less of the
phosphate compounds in terms of the amount of P.
6. The chemical treatment stecl shect according to any one of Claims 1 to 5,
wherein the chemical treatment layer contains less than 1 mg/m2 of the
phosphate compounds in terms of the amount of P.
7. The chemical treatment steel sheet according to any one of Claims 1 to 6.
wherein the chemical treatment layer contains 0.03 mg/m2 or greater ofthe
phosphate compounds in terms of the amount of P.
8. The chemical treatment steel sheet according to any one of Claims 1 to 7,
wherein when a variation amount in a yellowness index before and after
storage for 4 weeks in an environment of a temperature of 40°C and a humidity of 80%
at one measurement point on an outermost surface of the chemical treatment layer is
defined as AYI, an average value of the AYI obtained at the measurement points
included in a unit area of the outermost surface is less than 1.7.
9. The chemical treatment steel sheet according to any one of Claims 1 to 8,
wherein the composite coated layer contains 2 to 180 mg/m2 of Ni in terms of
the amount of metal Ni, and 0.2 to 8 ms/m2 of Sn in terms of the amount of metal Sn.
10. The chemical treatment steel sheet according to any one of Claims 1 to 9,
wherein a surface of the chemical treatment layer i~ not coated with a film or
a coating.
11. A method for producing a chemical treatment steel sheet, comprising:
a plating process that forms an Ni coated layer that contains 2 to 200 ing/m2
of Ni in terms of the amount of metal Ni and an Sn coatccl layer that contains 0.1 to 10
g/m2 of Sn in terms of the amount of metal Sn on a surface of a steel sheet;
a reflow process that forms an Fe-Ni-Sn alloy layer on the steel sheet and an
island-shaped Sn coated layer on the Fe-Ni-Sn alloy layer by perfonning a reflow
treatment with respect to the steel sheet in which the Ni coated layer and the Sn coated
layer are formed; and
a chemical treatment process that forms a chemical treatment layer on the
island-shaped Sn coated layer by performing an electrolytic treatment in a chemical
treatment liquid, which contains equal to or greater than 10 ppm and less than 500 ppm
of Zr ions, 10 to 20000 pprn of F ions, 10 to 3000 ppm of phosphate ions, and 100 to
30000 pprn in a total amount of nitrate ions and sulfate ions and of which a
temperature is set to equal to or higher than 5°C and lower than 9O0C, under conditions
of a current dcnsity of 0.5 to 20 ~ l d amnd~ an electrolytic treatment time of 0.05 to 10
seconds, or by performing an immersion treatment in the chemical treatment liquid for
an immersion time of 0.2 to 100 seconds.
12. The method for producing a chemical treatment steel sheet according to
Claim 11,
wherein the chemical treatment liquid contains 100 pprn to lessthan 500 ppm
of Zr ions, 100 to 17000 pprn of F ions, 20 to 2000 ppm of phosphate ions, and 1000 to
20000 pprn in a total amount of nitrate ions and sulfate ions