0001]The present disclosure relates to Mg-containing Zn alloy coating steel.
Background technique
[0002]
　Mainly Mg-containing Zn alloy plating having high corrosion resistance required in building materials sector, very hard, brittle. Therefore, easily cracked plating tissue during molding is at the interface between the plating layer and the plating layer and the steel material, the destruction of the peeling or the like occurs, a phenomenon that the plating layer is said to greatly deficient for powdering the result is observed. When powdering occurs, so that the corrosion resistance itself of the plated steel material is greatly reduced as a result.
[0003]
　Conventionally, the surface of the steel material by coating a metal such as Zn is widely known to improve the corrosion resistance of the steel, still coated Zn, Zn-Al, Zn- Al-Mg, Al-Si , etc. steel is produced in large quantities. These coatings steels, such as abrasion resistance in addition to corrosion resistance, are often required many functions. As the coating method is used hot dipping are most widely.
　This is hot dipping is suitable for mass production, bending, drawing, by performing processing such as welding, is because it is possible to manufacture many products.
　Corrosion resistance required for the coated steel yearly high, therefore in recent years has also been proposed plated with an increased Mg content more than ever as shown in Patent Documents 1 and 2 below. These plating 1) include Mg than conventional plating, 2) that the corrosion resistance of the flat portion of the above prior art by structural control is obtained, 3) that the corrosion resistance of the end surface or the like is obtained, 4) alkali atmosphere such as, conventional zinc-based or aluminum-based plating is characterized in that such a high corrosion resistance in the atmosphere to weak.
[0004]
　Apart from the continuous hot dipping of the steel sheet, immersion plating (groove pickled), spraying, techniques such as vapor deposition is a method from the viewpoint of coating product after processing, can be coated and less workability of the alloy. Among them, thermal spraying is less thermal influence on the steel for a coating method which does not immersed in the molten metal, is less restriction on the size of the steel material, the melting point tolerance of coatable metal or alloy systems such as wide there is an advantage.
　To increase the corrosion resistance in the plating is to include a Zn is basically the plating, if corrosion resistance is insufficient is large in plating containing only Zn for many applications. Therefore, Mg-containing spray coating, as described in Patent Document 3 have been proposed.
　This technique of Zn alloy containing Mg up to 0.3% and 15% as to spray the steel material surface, a thermal spray coating excellent in corrosion resistance and耐疵with resistance. Further, as shown in Patent Documents 4 and 5, but is limited to the weld, thermal spraying as a technique for improving the corrosion resistance has been proposed. These according to Patent Documents 4 and 5 techniques are spray coating of multilayer systems containing Zn, Al, Mg, Si and the like.
[0005]
　Other, Patent Document 6, the "mass%, Al: 13 ~ 78%, Ca: 1 contains 1-5% and is in a total amount of Al and Ca is less 79%, the remainder being Mg and unavoidable discloses a spray material "excellent in corrosion resistance of explosion-proof and spraying portion during thermal spraying, characterized in that it consists of impurities.
[0006]
Patent Document 1: Japanese Patent 2008-255464 JP
Patent Document 2: Japanese Patent 2011-190507 JP
Patent Document 3: Japanese Patent No. 3305573 discloses
Patent Document 4: Japanese Patent 2014-208880 JP
Patent Document 5: Japanese Patent 2012-107324 JP
Patent Document 6: Japanese Patent 4757692 JP
Summary of the Invention
Problems that the Invention is to Solve
[0007]
　However, melt plating film by plating composition processability is lowered, it thickened is difficult, or the possibility of such restricted to processing methods. Particularly non-equilibrium phase, strong tendency in film containing an intermetallic compound, it is also proposed in Patent Document 1 and Patent Document 2. Corrosion of the steel by coating the processed part is missing may be lowered significantly.
　Spray coating described in Patent Document 3, corrosion resistance, is not sufficient, especially corrosion resistance in the alkaline range but excellent耐疵with resistance. Spray coating described in Patent Documents 4 and 5, the first place because the coating of the prior art is lost by welding, which compensate for not be said corrosion, wear resistance is sufficient. For patent document 6 also, at present, there is still room for improvement.
[0008]
　One aspect of the present disclosure is to solve the above problems, a further increase in corrosion resistance than the prior art, and a high abrasion resistance, providing a steel having a metal coating layer having excellent 耐疵 with properties it is intended to.
Means for Solving the Problems
[0009]
　The present disclosure has been made based on the above background, including the following aspects.
[1] and a steel metal coating layer wherein arranged on the surface of the steel material, the metal coating layer, a particle diameter 5 ~ 100 [mu] m, be a laminated structure of the metal particles of flat shape having a thickness of 0.5 ~ 30 [mu] m ,
　the composition of the metal coating layer has a mass%, Zn: 11 ~ 80% , Al: 3 ~ 80%, Mg: 8 ~ 45%, Ca: 1 ~ 5%, and a Zn + Al> Mg satisfied,
　the metal coating layer, a quasi-crystalline phase, MgZn 2 and phase consists of a remaining structure, the quasi-crystalline phase and the MgZn 2 and a total area fraction of the phase 45% or more, the area fraction of the remaining structure is 0 is 55%, the quasi-crystalline phase area fraction of is 20% or more, the MgZn 2 Mg-containing Zn alloy coating steel area fraction of phases is 3% or more.
[2] The content of the Al is in mass%, Mg-containing Zn alloy coating steel according to a 3% or more and less than 13% [1].
[3] Mg-containing Zn alloy coating steel according to [1] or [2] having an oxide film having a thickness of 1 nm ~ 1000 nm which covers the surface of the metal particles.
[4] Mg-containing Zn alloy coating steel according to any one of the metal coating layer is a spray coating layer [1] to [3].
[5] The composition of the metal coating layer has a mass%, Y: 0% ~ 3.5 %, La: 0% ~ 3.5%, Ce: 0% ~ 3.5%, Si: 0% ~ 3.5%, Ti: 0% ~ 0.5%, Cr: 0% ~ 0.5%, Co: 0% ~ 0.5%, Ni: 0% ~ 0.5%, V: 0% ~ 0.5%, Nb: 0% ~ 0.5%, Cu: 0% ~ 0.5%, Sn: 0% ~ 0.5%, Mn: 0% ~ 0.2%, Sr: 0% ~ 0.5%, Sb: 0% ~ 0.5%, Pb: 0% ~ 0.5%, C: 0% ~ 0.5%, Fe: 0% ~ 0.5%, and Cd: 0% contain one or two or more to 0.5% and the following formula (a) and the following formula satisfies the (B) [1] ~ Mg-containing Zn alloy coating according to any one of [4] steel.
- formula (A): Ca + Y + La + Ce ≦ 3.5%
, formula (B); Ti + Cr + Co + Ni + V + Nb + Cu + Sn + Mn + Sr + Sb + Pb + C + Fe + Cd ≦ 0.5%
　in formulas (A) and formula (B), the chemical symbol shows the content of each element in mass% .
Effect of the invention
[0010]
　According to one aspect of the present disclosure can provide a Mg-containing Zn alloy coating steel extremely excellent corrosion resistance and abrasion resistance, and excellent耐疵with resistance. Thus, automotive applications, architectural applications, can provide steel that can be widely applied to residential use or the like, improvement of the members life, effective use of resources, reduction of environmental impact, maintenance effort, the reduction of cost by contributing, thereby contributing greatly to the development of the industry.
　One embodiment of the technology workpiece of the present disclosure, by applying to such steel has corrosion resistance over conventional Mg-containing coating, and a Mg-containing Zn alloy coating steel with high hardness excellent in corrosion resistance of alkali region it is possible to provide.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011]
Sectional view showing a coating steel material according to the embodiment of FIG. 1 the present disclosure.
[2] is a TEM electron beam diffraction image in quasicrystalline phase of the metal coating layer obtained in Example.
DESCRIPTION OF THE INVENTION
[0012]
　The present inventors, as a corrosion-resistant coating layer, with showing the Zn-Mg-Al-Ca-based quasi-crystal phase of the metal coating layer containing a high corrosion resistance and wear resistance, that also exhibit 耐疵 with resistance heading result of investigation of the processability of the metallization layer of the system, thereby achieving the present disclosure. This is a very effective tissue tissues including quasicrystalline phase corrosion, the improvement of the wear resistance and 耐疵 with resistance, due to the discovery of knowledge which forms a tissue that contains this quasicrystalline phase by thermal spraying.
[0013]
　Hereinafter, corrosion resistance according to an embodiment of the present disclosure, the Mg-containing Zn alloy coating steel which is excellent in wear resistance and耐疵with resistance will be described.
　In the present specification, the numerical range expressed using "to" means a range including numerical values described before and after "to" as the lower and upper limits.
　In this specification, "%" indicating the content of the component (element) means "% by mass".
[0014]
　Mg-containing Zn alloy coating steel 1 according to the embodiment of the present disclosure, for example, as shown in the cross-sectional structure of FIG. 1 (sectional structure taken along the coating layer thickness direction), the steel plate, steel pipe, civil engineering materials (guardrail, stop waterwall, corrugated tube or the like), the housing of consumer electronics member (air conditioner outdoor unit, etc.), automotive parts (suspension member or the like) steel 2 and the metal coating layer formed by thermal spraying on the surface of the steel material 2, such as (spray coating consisting of a layer) 3. Metallization layer 3 is thinner than the metal coating layer 3, a laminated structure of a plurality of metal particles 5 flat in having a particle size of several times the own thickness. In the metal layer 3, for example, metal particles 5, more in the plane direction along the surface of the steel material 2, while being positioned so that the surface of the steel material 2 covered without gaps, steel above the surface of the steel material 2 2 more in the thickness direction is deposited such that no gap. In other words, the metal coating layer 3 is, for example, a plurality of metal particles 5 of the flat is composed of a structure stacked in stone wall.
[0015]
　Further, for example, the interface between the metal particles 5 on the surface and the lowermost layer of the steel material 2 (interface between the steel material 2 and the metallization layer 3) Fe-Al alloy layer 2A is formed. After adhering to the metal particles 5 steel sheet surface, in order to coagulate in a very short time, the Fe-Al alloy layer 2A is different from the case of a general hot-dip plating, oxide film of the metal particles 5 surface to be described later very thin and it has a thickness of less than equal to.
[0016]
　Further, the surface of each metal particle pentoxide film is formed, distinct interface 5b is formed between the metal particles, as shown in FIG. Oxide film formed on the surface of each metal particle 5, the metal droplets in a molten state during the spraying is deposited on the surface of the steel material 2 by flying through the air, is the oxide film produced at the time of solidification . The thickness of the oxide film covering the surface of the metal particles 5, for example, a thickness of about 1 nm ~ 1000 nm. In other words, to have an oxide film having a thickness of 1 nm ~ 1000 nm which covers the surface of the metal particles shows that the metal coating layer 3 is formed by thermal spraying.
[0017]
　There is no particular limitation on the material of the steel product 2. Steel 2, e.g., generally steel, Ni pre-plating steel, Al-killed steel, it is possible to apply a portion of the high alloy steel. There is no particular limitation on the shape of the steel 2.
[0018]
　Fe-Al alloy layer 2A is formed on the surface of the steel material 2, for example, Al as a tissue 3 comprises Fe phase and Zn phase, the average composition of Fe: 30 ~ 50%, Al : 50 ~ 70%, Zn : 2-10%, and the balance consisting of impurities. Fe-Al alloy layer 2A is formed by the reaction of Fe droplet and a steel second surface of the molten metal particles during thermal spraying because it contains a large amount of Al and Zn in the metal particles 5, as described later. Al and Zn contained in the Fe-Al alloy layer 2A is one in which Al and Zn contained in the Zn-Mg-Al alloy constituting the metal particles 5 was included results were partially diffused.
[0019]
　Hereinafter, the size and structure of the metal particles 5, and will be described tissues and composition of the metal coating layer 3.
　Metal particles 5, quasicrystalline phase 5a and MgZn 2 composed of a phase and the remaining structure. In metallization layer 3 that the metal particles 5 are stacked, quasicrystals organization and MgZn 2 total area fraction of the phase is 45% or more, the area fraction of the remaining structure is 0 to 55% quasicrystalline phase the area fraction of is 20% or more, MgZn 2 is the area fraction of phases is 3% or more.
[0020]
　The metal particles 5 need not have an area fraction described above, the metal coating layer 3 of a laminated structure may be in the range of area fraction above. Therefore, looking at a plurality of metal particles 5 individually and also as the metal particles 5 not containing quasicrystalline phases 5a had some, quasicrystalline phase 5a is present in the other metal particles 5, the metallization layer 3 20% or more quasicrystalline phases 5a may exist throughout. Therefore depicts so no quasicrystalline phases 5a in a part of the metal particles 5 in Figure 1.
[0021]
　In other words, structure of the metal coating layer 3, the quasi-crystal phase and MgZn 2 consists of a phase and remaining structure, the quasi-crystal phase and MgZn 2 total area fraction of the phase is 45% or more, the area fraction of the remaining structure There is 0 to 55% area fraction of the quasi-crystal phase is 20% or more, MgZn 2 is the area fraction of phases is 3% or more.
[0022]
　Here, quasi-crystalline structure and MgZn 2 total area fraction of the phase, more preferably at least 50%. On the other hand, quasi-crystalline structure and MgZn 2 total area fraction of the phase, from the viewpoint of industrial productivity, preferably 80% or less.
　Area fraction of the remaining structure, from the corrosion resistance viewpoint, more preferably 0-20%.
　Area fraction of quasicrystalline phase, the corrosion resistance viewpoint, more preferably at least 25%. On the other hand, the area fraction of the quasi-crystal phase from the viewpoint of industrial productivity, preferably 45% or less.
　MgZn 2 phase area fraction of from corrosion resistance point, and more preferably 20% or more. On the other hand, MgZn 2 area fraction of phases, from the viewpoint of industrial productivity, preferably 40% or less.
[0023]
　Particle size and thickness of the metal particles 5 constituting the metal coating layer 3 is a generally determined by the size and spraying conditions of the spray before the metal particles. Metal particles 5 solidifies collision, in a very short time and deformed at a high speed steel 2 surface in a semi-molten state outermost layer is melted. The size of the parallel direction of the metal particles 5 (the direction parallel to the surface of the steel material 2) becomes larger than the particle size of the metal particles 5 before spraying, the thickness of the metal particles 5 is smaller than the particle size of the metal particles 5 before spraying from becoming, the shape of the metal particles 5 a deed flat shape. Further, since through the production process, such as described above, since the planar shape of the metal particles 5 is perfect circle is rare, the particle size of the metal particles 5 are of a straight line diameter of the particles becomes maximum length to be. The thickness of the metal particles 5, the length of a straight line is perpendicular at and up to a straight line diameter of the particles becomes longest.
[0024]
　Particle size 5 ~ 100 [mu] m of the metal particles 5, the thickness is preferably 0.5 ~ 30 [mu] m. It is more preferred particle size of the metal particles 5 are 20 ~ 80 [mu] m, the thickness is 1 ~ 15 [mu] m.
　The aspect ratio of the metal particles 5 (thickness / particle size) is preferably, and more preferably in 1 / 80-15 / 80 0.5 / 100-30 / 100.
[0025]
　Incidentally, confirm the shape and size of the metal particles 5 to form a metal coating layer 3 is whether it satisfies the configuration of the present disclosure, be confirmed by sectional observation of the metallization layer 3 (the observation of a section cut into the coating layer thickness direction) Bayoi. Sample preparation methods for cross-sectional observation may be carried out by known resin embedding or cross-section polishing method.
　Specifically, the particle diameter, and the thickness of the metal particles 5 is measured as follows. Optical microscopy or SEM (scanning electron microscope), in which is cut in the thickness direction cross section of the cross-section observation (metallization layer 3 of the metallization layer 3, 2.5 mm length min in a direction parallel to the metallization layer 3 the observation) of the corresponding region to perform. In this region, the determining the particle size, and thickness of the average value of the metal particles observed in at least three field of view (500X magnification). The average particle diameter of the metal particles 5, and a thickness. Then, the aspect ratio of the metal particles is a value calculated from the particle size and the thickness of the metal particles of the average value.
　The thickness of the oxide film covering the surface of the metal particles is measured as follows. The SEM (scanning electron microscope), in which is cut in the thickness direction cross section of the cross-section observation (metallization layer 3 of the metallization layer 3, corresponding to 2.5mm length min in a direction parallel to the metallization layer 3 to observe) the area. In this region, among the metal particles 5 are observed in at least three field of view (magnification 10,000 times), selects three of the metal particles 5 per one visual field. Then, the thickness of the oxide film covering the surface of each metal particle 5 of three selected (at least a total of nine), measured at arbitrary three points for each particle and calculate the average. And the average value is set as the thickness of the oxide film.
[0026]
　The particle size of the metal particles 5 cause elimination of degradation or coating corrosion cracks easily enter in grains exceeds 100 [mu] m. Particles having a particle size of less than 5μm reaches the steel sheet at a very low speed, there is less deformation possibility, adhesiveness may be reduced. Also, undesirable reduces the feedability Reducing the particle size of the initial metallic particles, productivity is lowered.
[0027]
　If the thickness of the metal particles 5 exceeds 30 [mu] m, causing elimination of reduced or coating corrosion resistance tends to be cracked in the grains. Or variations adhesion due to the smaller also be impaired. Particles having a thickness of less than 0.1μm reaches the steel sheet at a very low speed, there is less deformation possibility, adhesiveness may be reduced.
[0028]
　Then, the quasi-crystal phase of the metal coating layer 3, MgZn 2 phase, and the measuring method of the area fraction of the remaining structure will be described.
　Any cross-section of at least 3 or more visual fields (at least 3 viewing a region corresponding to 500μm length min in a direction parallel to the metallization layer 3 at a magnification of 5,000 times (cross section cut in the coating layer thickness direction) of the metallization layer 3 above) the SEM- shooting in reflected electron image. From experimental results obtained by separately TEM observation, quasicrystalline phase in SEM- reflected electron image, MgZn 2 identifies phase, and the remaining structure. In certain field, grasps the component mapping image, quasicrystalline phase in the metal coating layer 3, MgZn 2 phase, and to identify the same component composition places the remaining structure, the image processing, the quasi-crystal phase in the metal coating layer 3 , MgZn 2 identifies phase, and the remaining structure. By image analysis apparatus, quasicrystalline phase, MgZn 2 phase, and prepare an image that is a range selected each region remaining structure, the quasi-crystal phase occupied in the metal coating layer 3, MgZn 2 phase, and the ratio of the remaining structure Measure. The average value of from similarly treated 3 field, the quasi-crystal phase in the metal coating layer 3, MgZn 2 phase, and an area fraction of the remaining structure.
[0029]
　Phase identification metallization layer 3, the metal coating layer 3 cross-section (cut the coating layer thickness direction cross-section) FIB (focused ion beam) was subjected to machining, electron diffraction of TEM (transmission electron microscope) carried out by the image.
[0030]
　Composition of the metal coating layer 3, by mass%, Zn: 11 ~ 80% , Al: 3 ~ 80%, Mg: 8 ~ 45%, Ca: 1 ~ 5%, and preferably satisfy the Zn + Al> Mg. Specifically, the composition excluding oxygen of the metal coating layer 3, Zn in weight%: 11 ~ 80%, Al : 3 ~ 80%, Mg: 8 ~ 45%, Ca: 1 ~ 5%, and the balance: consists impurity, Zn content, Al content and Mg content Zn + Al> Mg (total Zn content and Al content> Mg content) is more preferably satisfied.
　Note that the impurity components contained in the raw material, or a component mixed in the manufacturing process, refers to a do not have intentionally containing component.
[0031]
　First, the composition of the metal coating layer 3, numerical limitation range and the reasons for limitation will be explained.
"Zn (Zinc): 11-80%"
　metallization layer 3 (i.e., the metal particles 5 constituting the metal coating layer 3) in order to obtain a quasi-crystalline phase as a metal structure of contains Zn in the range. Therefore, the Zn content of the metal coating layer 3 and 11 to 80%. If Zn content is less than 11%, it is impossible to generate a quasi-crystal phase in the metal coating layer 3. Similarly, if Zn content is 80%, it is impossible to generate a quasi-crystal phase in the metal coating layer 3.
　In order to further improve the corrosion resistance by generating preferably quasicrystals, the Zn content in the metal coating layer 3 is preferably set to 33% or more. When 33% or more, quasicrystalline phase becomes grow easily composition range as primary crystal, Mg phase is less likely to grow as a primary crystal. That is, it is possible to increase the phase volume of the quasi-crystal phase (area fraction) of a metal coating layer 3, it is possible to reduce Mg phase deteriorate the corrosion resistance as much as possible. More preferably, the Zn content in the metal layer 3 is 35% or more. Usually, by forming the metal coating layer 3 in and spraying method in this composition range, Mg phase hardly exists.
[0032]
　"Al (aluminum): 3-80%"
　Al is an element that improves the corrosion resistance of the flat portion of the covering steel. Further, Al is an element promoting the formation of the quasi-crystal phase. To achieve these effects, and the Al content of the metal coating layer 3 3% or more. On the other hand, when a large amount of Al in the metal coating layer 3 is contained, along with red rust is likely to occur, the corrosion resistance hardly generated quasicrystalline phase decreases. Thus, the 80% upper limit of the Al content of the metal coating layer 3. In order to facilitate the generation of the quasi-crystal phase, Al content is preferably less than 3% or more 13%, and more preferably set to 5 to 50%. Incidentally, Al, it is preferable element contained in forming the Fe-Al interface alloy layer 2A.
[0033]
　Here, the present inventors have, as a result of investigating the relationship between the thickness and components of the Fe-Al alloy layer 2A, large thickness of the metal when the Al content of the coating layer 3 becomes 13% or more Fe-Al alloy layer 2A there was to become trend. Too thick Fe-Al alloy layer 2A is caused a decrease in Al content of the metal coating layer 3, except that it is difficult to form quasi-crystalline phase, it is avoided in order to degrade the corrosion resistance and performance of the metallization layer 3 preferable. Therefore, from the viewpoint of thinning the Fe-Al alloy layer 2A, Al content is preferably less than 3% or more 13%, and more preferably 5% to 50% or less.
　Incidentally, originally, Mg has no reactivity with Fe, dropped activity of Zn and Al, and has a reactivity with moderate base steel. Therefore, it is suitable as an alloy for metal coating layer 3. On the other hand, if the Al concentration is high, a short time of spraying time so as not to excessively proceed reactive metallization layer 3 and the base steel, speed, etc. of the spray rate, it is better to take heat treatment conditions.
[0034]
　"Mg (magnesium): 8-45%"
　Mg, as well as the Zn and Al, a major element forming the metal coating layer 3, furthermore, an element improving the sacrificial protection property. Moreover, Mg is an important element for promoting the formation of the quasi-crystal phase.
　That, Mg content may be 45% or less than 8%, preferably 35% to 15% or less. On the other hand, possible to suppress Mg contained is precipitated as Mg phase with a metal coating layer 3 is preferred for improving corrosion resistance. That, Mg phase, since the deterioration of the corrosion resistance, Mg contained is quasicrystalline phase, or be a constituent of other intermetallic compound.
[0035]
　"Ca: 1 ~ 5%"
　Ca is an element for improving the runnability of thermal spraying. The spraying method retain high molten Mg alloy oxidation resistance after thermal spraying in the air. Therefore, it is preferable to take oxidation prevention means some Mg. Ca is easily oxidized than Mg, to prevent oxidation of Mg metal particles 5 to form a stable oxide film on the metal particles 5 in a molten state. Therefore, the Ca content of the metal coating layer 3 and 1-5%.
　When a is contained more than 1 wt% Ca, since the metal coating layer 3 higher Mg content can be held without being oxidized in the atmosphere preferred. Meanwhile, Ca is easily oxidized because it may adversely affect the corrosion resistance, it is preferable that the 5% limit.
[0036]
　The metal coating layer 3, Y: 0% to 3.5%, La: 0% to 3.5%, and Ce: 1 or 0% to 3.5%, or even contain more than good. However, the formula (A): Ca + Y + La + Ce ≦ 3.5% ( wherein each element symbol represents the content of each element (mass%).) May be preferably satisfied.
　Y, La, and Ce, by certain concentration is contained in the spray particles, quasicrystalline phase is more easily formed. On the other hand, if the Ca concentration is high, or Ca, Y, La, and when the total concentration of Ce is high, since the quasi-crystalline phase is not formed in the tin, it is preferable to determine the respective upper concentration.
[0037]
　The metal coating layer 3, Si: 0% ~ 3.5% , Ti: 0% ~ 0.5%, Cr: 0% ~ 0.5%, Co: 0% ~ 0.5%, Ni: 0% ~ 0.5%, V: 0% ~ 0.5%, Nb: 0% ~ 0.5%, Cu: 0% ~ 0.5%, Sn: 0% ~ 0.5%, Mn: 0% ~ 0.2%, Sr: 0% ~ 0.5%, Sb: 0% ~ 0.5%, Pb: 0% ~ 0.5%, C: 0% ~ 0.5%, Fe: 0% to 0.5%, and Cd: 1 or from 0% to 0.5% or may contain two or more. However, formula (B); Ti + Cr + Co + Ni + V + Nb + Cu + Sn + Mn + Sr + Sb + Pb + C + Fe + Cd ≦ 0.5% ( wherein each element symbol represents the content of each element (mass%).) May be preferably satisfied.
　These elements are possible to be contained in the metal coating layer 3, the formula (B), without inhibiting the formation of the quasi-crystalline phase, without degrading the performance of the metallization layer 3, each element a composition range which can be contained. Beyond the scope of this formula (B), the quasi-crystalline phase is difficult to form.
[0038]
　Zn, Al, and Mg is from an element constituting the quasicrystals, always need to be contained in a range metallization layer 3 described above, at the outside the above-mentioned composition range, the quasi-crystal phase of 20% or more, metallization layer 3 (Zn-Mg-Al alloy layer) can not be included in the.
　From the viewpoint of formation of the quasi-crystal phase, the composition of the metal coating layer 3, Zn: 11 ~ 72%, Al: 5 ~ 67%, Mg: 10 ~ 35%, Ca: 1 ~ 5%, and Zn + Al> Mg more preferably satisfies, Zn: 35 ~ 70%, Al: 3 ~ 42%, Mg: 15 ~ 25%, Ca: 1.4 ~ 3%, and more preferably to satisfy the Zn + Al> Mg, Zn: 35 ~ 70%, Al: 5 ~ 13%, Mg: 15 ~ 25%, Ca: 1.4 ~ 3%, and it is particularly preferable to satisfy the Zn + Al> Mg.
[0039]
　Metal composition of the covering layer 3 is outside the range described above is basically the composition paracrystalline it becomes difficult to obtain. Moreover, further metallization layer 3 becomes hard, easily peeling occurs metallization layer 3 may also be in the range of the composition is not suitable as the metal coating layer 3.
[0040]
　Composition of the metal coating layer 3, as well as the measuring method of thickness measurement method of the thickness of the metallization layer 3 and the Fe-Al alloy layer 2A is as follows.
　First, is peeled off only the upper layer of the metal coating layer 3 to passivate the Fe-Al alloy layer 2A by fuming nitric acid, the solution ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometry) or ICP-MS (Inductively Coupled Plasma at Mass Spectrometry), for measuring the composition of the metal coating layer 3.
[0041]
　Here, in the metal coating layer 3, the quasi-crystalline phase, Mg content in the quasicrystalline phase, Zn content and Al content, in atomic%, 0.5 ≦ Mg / (Zn + Al) ≦ 0. It is defined as a quasi-crystal phase satisfies 83. That is, the Mg atoms, Mg is the ratio of the sum of Zn atoms and Al atoms: the (Zn + Al), 3: 6 ~ 5: is defined as 6 to become quasi-crystal phase. The theoretical ratio, Mg: (Zn + Al) of 4: believed to be 6.
Chemical components of the quasi-crystalline phase, quantitative analysis and by TEM-EDX (Transmission Electron Microscope- Energy Dispersive X-ray Spectroscopy), it is preferable to calculate in quantitative analysis by EPMA (Electron Probe Micro-Analyzer) mapping. Incidentally, it is not easy to define the quasi-crystals in the correct chemical formula as intermetallic compounds. Quasicrystalline phase can not be defined a grid unit of repeating such a unit cell of the crystal, and further, Zn, because also difficult to identify the atomic positions of Mg.
　The metal coating layer 3, MgZn besides quasicrystalline phase 2 including phase and remaining structure, the remaining structure is the quasi-crystal phase and MgZn 2 a phase other tissues, Mg 51 Zn 20 phase, Mg 32 ( Zn, Al) 49 phase, MgZn phase, Mg 2 Zn 3 phase, Zn phase include Al equality.
[0042]
　Quasicrystalline phase is the first discovered crystalline structure by Daniel Shuhitoman in 1982, and has an atomic arrangement in the icosahedron (icosahedron). The crystal structure, usually of metal, specific rotational symmetry which can not be obtained in the alloy, in a non-periodic crystal structure having, for example, 5-fold symmetry, aperiodic structure equivalent represented by 3-dimensional Penrose pattern It is known as Do not crystal structure. This in order to identify the metal material, typically by electron beam observation by TEM observation, the phase is confirmed by obtaining a radial positive decagonal electron beam diffraction image due to the icosahedral structure. For example, an electron beam diffraction image shown in FIG. 2 to be described later is obtained only from the quasicrystals, not be obtained from any other crystal structure.
[0043]
　Further, the quasi-crystalline phase obtained by the chemical composition of the metal alloy layer 3 is the simplified, Mg 32 (Zn, Al) 49 by X-ray diffraction as a phase, JCPDS card: PDF # 00-019-0029, or, # shows the diffraction peaks can be identified in 00-039-0951.
　Quasicrystalline phase is a material excellent in a very corrosion resistant, metal alloy layer 3 (Zn-Mg-Al layer) when contained corrosion resistance is improved in the. Especially in an area fraction of 5% or more, tends to white rust is suppressed in corrosion initial stage are contained in the metal alloy layer 3. For example a higher area fraction, increasing its effectiveness when it is contained 20% or more. That quasicrystalline phase formed on the surface of the metal alloy layer 3 (Zn-Mg-Al alloy layer) has a high barrier effect against corrosion factor.
[0044]
　Further, when the quasi-crystalline phase in accelerated corrosion test or the like is corroded, highly corrosion products form a barrier effect and anti-corrosion of the base steel for a long time. High corrosion products Accessible effect, Zn-Mg-Al component ratio contained in the quasi-crystal phase is concerned. In the component composition of the metal alloy layer 3 (Zn-Mg-Al alloy layer), Zn> Mg + Al + Ca (wherein the element symbol content of the element (shown by mass%)) if has been established, the corrosion products barrier effect is high. In general, corrosion resistance, higher is the area fraction of quasicrystalline phase. The effect when the area fraction of the quasi-crystal phase is 80% or more is particularly large. These effects, in combined cycle corrosion test including the salt spray cycle (SST), the effect is largely appears.
[0045]
　MgZn 2 phase, and Mg 2 Zn 3 phase, compared with the quasi-crystal phase, but the corrosion resistance improving effect by the content is small, has a constant corrosion resistance, and, since it contains a large amount of Mg, excellent alkali corrosion resistance. Alkali corrosion resistance can be obtained by also contained in the metal coating layer 3 in these single intermetallic compound, quasicrystalline phase and comorbid the quasicrystalline phase of highly alkaline environment (pH 13 ~ 14) of the metallization layer 3 in oxide film of the surface layer is stabilized, so that particularly shows a high corrosion resistance. For this purpose, the quasi-crystalline phase must be contained more than 20% area fraction in the metal coating layer 3, and more preferably is contained 30% or more.
　For example, in a state containing a quasi-crystalline phase in the metal coating layer 3, as the residual phase, MgZn 2 phase, Mg 2 Zn 3 containing phase, semi-crystalline phase, MgZn 2 phase, and Mg 2 Zn 3 area fraction of If is made 75% or more in total, to improve the corrosion resistance in the alkaline range. For example, it is possible to obtain a strongly alkaline environment, ammonia water, an excellent alkali corrosion resistance as the amount of corrosion even in caustic soda is substantially zero.
[0046]
　Within the composition quasicrystalline phase is obtained, other quasicrystals, sometimes Al phase as the remaining structure is mixed in the metal coating layer 3. Al phase has a plastic deformability with a very soft plating, when containing these phases, plastic deformability occurs in the metal coating layer 3.
　Al phase in the metal coating layer 3 is contained in an area fraction 50% or more, and when it exceeds 75%, the total of the area fraction of the quasi-crystalline phase, ductility born metallization layer 3, for example, impact excellent sex, when implementing the ball impact test, peeling of the metal coating layer 3 is significantly reduced.
[0047]
　"Method for forming the metal coating layer 3"
　to form a metal coating layer 3, providing a powder or wire thermal spray material blended with each element so as to have the composition described above. As an example, in order to obtain a powder, each metal such that the desired composition and dissolved housed in a heat-resistant container such as a crucible and is solidified. When dissolving each metal, it is desirable to use a small metal block in order to uniformly mix. Atmosphere in the case of heating and dissolving is desirably an inert gas atmosphere to avoid contamination of impurities, for example, it is desirable to employ an oxygen concentration of 1% or less atmosphere.
　When solidifying, it is possible to use a solidification means utilizing a atomizing method, was allowed to solidify in the crucible, the solidification was also possible to powdered by grinding.
[0048]
　The particle size of the powder used in the spraying is not particularly limited, the area of the metallization layer 3 that is required, in consideration of such a thickness, it is possible to select the desired range at any time. For example, it is possible to select a particle size of about 50 [mu] m ~ 200 [mu] m.
　Spraying method can be employed plasma spraying, such as arc spraying.
　Alloy of the desired composition is powdered can be easily in a very brittle because the pulverization method, since in the case of irregular particle shape, size coating efficiency decreases, it is desirable to triturated with atomizing method, Among them, it is desirable to employ a gas atomization oxidation is less of the surface. Further, it is desirable to use the powdered particles were further classified aligned to the particle size of the predetermined range particles.
[0049]
　Above prepared powder as described is supplied to the spray gun to perform thermal spraying to the surface of the steel material 2, by forming a thermally sprayed layer, the metal coating layer as a plurality stacked structure metal particles 5 shown in FIG. 1 3 can be obtained Mg-containing Zn alloy coating steel 1 coated on the surface of the steel material 2. Since spray gun injects as fine droplets by melting the spraying material can be obtained when depositing a coagulum of droplets on the surface of the steel material 2 metallization layer 3 in which a plurality of metal particles 5 are deposited .
[0050]
　Controlling the area fraction of metal coating layer 3 (metal particles 5 constituting the metal coating layer 3) of the quasi-crystal phase (i.e., phase area fraction of the tissue of the metallization layer 3) temperature to control is effective. 500 for ~ 350 ° C. The most stable to phase in a temperature range of a quasi-crystalline phase, semi-crystalline phase of the metal layer 3 in (Zn-Al-Mg alloy layer) by prolonging the holding time in this temperature range it is possible to improve the area fraction of. More preferably, retains more than 30 seconds, it is preferable that below the cooling rate of 5 ° C. / sec. By below this cooling rate, it is possible to maximize generate the precipitation of quasicrystalline phase. For example, when more than 5 ° C. / sec during which the cooling rate, the proportion of quasicrystalline phase originally obtained in extremely small tendency. Somewhat when too large, is cooled before the quasi-crystal phase is precipitated, containing quasicrystalline phase is reduced.
[0051]
　On the other hand, in the temperature range of 250 ° C. or less than 350 ° C., Mg than quasicrystalline phase 2 Zn 3 phase, Mg phase, to enter a stable region of the intermetallic compound phase MgZn equality, increase the cooling rate in this temperature range There is a need. Preferably, it is possible to maintain the maximum value of the area fraction of the metallization layer 3 (Zn-Al-Mg alloy layer) in the quasi-crystal phase by a 10 ° C. / sec or more cooling rate.
[0052]
　In other words, the metal coating layer 3 performs spraying to the surface of the steel material 2 by supplying an alloy powder component composition of interest spray gun to form a sprayed layer. Thereafter, in the course of cooling, 500 ° C. and held below 350 at a temperature range below ° C. cooling rate 5 ° C. / as fractional seconds 30 seconds or more, the cooling rate in a temperature range of 250 ° C. or less than 350 ° C. 10 ° C. / sec or more and it is preferable to.
　The cooling rate of the temperature range below 250 ° C. is unquestioned. The atomic diffusion low temperature in a temperature range becomes weak, because is below longer generation phase, the temperature required for decomposition.
[0053]
　How to obtain this quasicrystalline phase, it is various, but for thermal spraying, for those relatively often keep the tissue powder during starting, preheating before the powder spraying is effective. Specifically, for example, a powder before spraying, it is preferable to preheat treated with 100 ~ 200 ° C.. It can control the organization of the sprayed particles to fasten tissue during starting by advance the phase structure of interest.
　The particle became particle surface and completely melted state becomes semi-molten state, spraying conditions (stacking path distance, the spray gun and distance of the steel material, the preheating temperature of the steel) by selecting, are laminated later it can be obtained particles, such as spray arc heat, the quasi-crystal phase area fraction of interest by controlling well the heat removal to the steel.
[0054]
　Here, with the heat treatment, the adhesion of the steel 2 and the metal coating layer 3 is improved by Al-Fe alloy layer is formed. However, too thick Fe-Al alloy layer 2A is caused a decrease in Al content of the metal coating layer 3, except that it is difficult to form quasi-crystalline phases and deteriorates the corrosion resistance and performance of the metallization layer 3. Therefore, in order to metallization layer 3 serving as the object of the composition and tissue, by controlling the heat treatment temperature and time and composition of the metal coating layer 3, the thickness of the Al-Fe alloy layer 2A be 1 ~ 1000 nm preferable. Too thick than 1000nm caused a decrease in Al content of the metal coating layer 3, the formation of the quasi-crystal phase becomes difficult. Also, if the Al-Fe alloy layer 2A is 1nm or less, the adhesion of the metallization layer 3 and the steel material 2 becomes insufficient. The thickness of the Al-Fe alloy layer 2A is preferably 100 ~ 500 nm.
[0055]
　The thickness of the Al-Fe alloy layer 2A is measured as follows. SEM by (scanning electron microscope), the Al-Fe sectional observation of the alloy layer 2A (Al-Fe alloy layer 2A is cut in the cross section in the thickness direction of, 2.5mm to Al-Fe alloy layer 2A and the direction parallel to to observe the area) corresponding to the length minute. In this region, determining at least three field of view the thickness of the average of any five locations of each Al-Fe alloy layer 2A to be observed (magnification 10,000 times) (at least a total of 15 points). And the average value is set as the thickness of the Al-Fe alloy layer 2A.
　The thickness of the metal coating layer 3, and the average value was measured in the same manner as the thickness of the Al-Fe alloy layer 2A.
　Incidentally, sample preparation methods for cross-sectional observation may be carried out by known resin embedding or cross-section polishing method.
[0056]
　In metallization layer 3 obtained based on the production method and the cooling process described above, the metal coating layer 3 having a laminated structure of the metal particles 5 Zn-Al-Mg alloy containing a predetermined percentage of the quasi-crystal phase steel and it covers the second surface. Therefore, the metal coating layer 3 is hard, excellent in wear resistance, excellent corrosion resistance is also excellent in corrosion resistance in an alkaline region. Therefore, the surface is hard and excellent in wear resistance, excellent corrosion resistance, can provide a Mg-containing Zn alloy coating steel 1 which is excellent in corrosion resistance in an alkaline region.
[0057]
　Further, in the previous embodiment the surface has been described structure coated with a metal coating layer 3 on a smooth steel 2, steel is uneven on the surface, of the cross-section profiled steel, such as steel is bent, of any shape steel if spraying is a steel shapes possible in, not limited to the presence or absence of shape or irregularities of the steel, it is possible to apply the present disclosure structure. Therefore the techniques of this disclosure are capable of providing regardless of the shape of the steel.
[0058]
　The present disclosure also in the preparation of Mg-containing Zn alloy coating steel, may be carried out post-treatment after forming the metal coating layer.
　The post-treatment, various processes can be mentioned to treat the surface of the coated steel, process for performing upper plating, click port mail Bok treatment, non-chromate treatment, phosphate treatment, lubricity-improving treatment, weldability improving treatment such as there is. Further, as a post-treatment after forming the metal coating layer, resin paint (e.g., polyester resin, acrylic resin, fluororesin, vinyl chloride resin, urethane resin, epoxy resin, etc.), roll coating , spray coating, curtain flow coating, dip coating, film lamination method (for example, a film lamination method at the time of laminating a resin film such as an acrylic resin film) by coating by a method such as is also the process for forming a coating film .
Example
[0059]
　Be described in further detail with reference the disclosure now to examples.
　JIS G 3101 (2010) prescribed SS400 (first steel: length 150 mm, width 70 mm, thickness 3.2 mm) and, JIS G 3101 (2010) prescribed SS400 (second steel: length 180 mm, width 70 mm, thickness the 1.6 mm) as a test piece was used to spray the following tests. However, the second steel was used to spray the following tests and processing the position of 30mm from its one end to 90 ° bend flexural test piece R2.0Mm. Incidentally, it referred to the test piece of the first steel not subjected to bending as a "flat test piece" hereinafter.
[0060]
　Thermal spraying powder is, Zn- (15 ~ 45) mass% Mg- (3 ~ 15) mass% Al- (2 ~ 5) wt% Ca a composition ratio (Zn mass% of the balance) particle size 50 It was used of ~ 200μm. Particle shape of the thermal spraying powder was cheek spherical.
　Further, as the thermal spray powder for comparison, a commercially available Al powder (average particle size 100 [mu] m), Zn powder (average particle size 250 [mu] m), Mg powder (average particle size 280 .mu.m) are prepared respectively, used alone in response to the test It was used as a mixture or.
[0061]
　Using an atmospheric pressure plasma arc spraying method, the working gas Ar-H 2 a thermal spray powder of interest was supplied with argon gas in were generated as gas plasma. The distance between the spray gun and the steel (base material) is set to 100 mm, moving the spray gun so that the temperature of the substrate does not exceed 500 ° C., by repeating the spraying, the thickness of the formed metal coating layer (described later and controlling the thickness) in accordance with the evaluation test to be. Then, after spraying the thermal spraying powder in the preheating temperature shown in Table 1, the thermal spray powder sprayed from the spray gun to form a metal coating layer on the surface of the flat test piece (first steel).
　Cooling conditions, the cooling rate from solidification to 350 ° C. below 3 ° C. above 5 ° C., was cooling rate from 350 ° C. to 250 ° C. in a range of less than 10 ° C. or higher 15 ° C..
　And some specimens (eg symbol Z) was the distance of the spray gun and the substrate and 150 mm.
　Using the same spray gun, formed on the surface of Al powder to be compared, Zn powder, or each plane specimen plane specimen above the metallization layer with a mixed powder thereof (first steel).
[0062]
　On the other hand, bending the bending inner portions bent using multi-axial spraying robot on the surface of the test piece (second steel) to form a metal coating layer of sprayed respective outer.
[0063]
　The composition of the produced metal coating layer in Table 1 below. Incidentally, each phase area fraction was measured according to the method described above.
[0064]
"Production of the molten plating material"
　Incidentally, for comparison, were prepared steel (hereinafter "planar molten plating material") having a metal coating layer of hot-dip plating of a plurality of compositions. Substrate for hot-dip plating is, JIS G 3101 (2010) length 180 mm, width 70mm consisting defined SS400, using steel plate having a thickness of 1.6 mm. The composition of the metal coating by hot dipping are shown in Table 1. The thickness of the metal coating layer by hot-dip plating were the same as the metal coating layer by spraying.
[0065]
[Table 1]

[0066]
　"Corrosion resistance evaluation"
　corrosion resistance was evaluated by accelerated corrosion test. Accelerated corrosion test was carried out in the salt spray test using aqueous 5% NaCl solution as defined in JIS Z2371 (SST). Were tested to 6000Hrs at maximum, each of the flat test piece, and red rust was compared with time occurring in the plane molten plating material. End face None of specimens, the backside was sealed with tape. All the thickness of the metallization layer was 25 [mu] m.
　On the other hand, similarly, for the bending test piece was conducted, respectively inner evaluation and outside evaluation of the bending portion. Also, performed after plating, one for even the position of 30mm from the edge by R2.0Mm 90 ° bending was bending the bending was applied to the planar molten plating material melted plating material, inner evaluation and outside evaluation of the bending portion, respectively It was.
[0067]
"Wear and耐疵with evaluation"
　abrasion resistance and耐疵with resistance using HEIDON Co., a linear sliding tester. Contact portions steel ball: and (20R material SKD11), and a load 500 g, sliding distance 40 mm, the speed of 1200 mm / min. After 10 reciprocal, each flat specimens, and was visually observed the surface of the planar molten plating material. All the thickness of the metallization layer was 12 [mu] m.
　After the test, each of the flat specimens, and the surface of the planar molten plating material, the apparent scratches and if Kakegami was a "G4". Those non-test unit is clearly shade has changed compared to the test unit was "G3". Those non-test unit is slightly shade changes as compared to the test unit "G2" and what pre-test and appearance hardly changed as "G1".
[0068]
　The results of corrosion resistance evaluation test are shown in Table 2 to Table 3 below, are shown in Table 4 below the results of the abrasion resistance and 耐疵 with evaluation test.
[0069]
[Table 2]

[0070]
[table 3]

[0071]
[Table 4]

[0072]
　As shown in Table 2 steel having a metal coating layer according to the thermal spraying of the present disclosure is to SST6000 hours, either no red rust, it showed high corrosion resistance. Of comparative material, a part of the plating good corrosion resistance at the portion without machining, there is separation of plating (powdering) by machining, the corrosion resistance was significantly reduced in the processing unit. Further, the steel having a metal coating layer according to the thermal spraying of the present disclosure as shown in Table 3 showed to have excellent wear resistance and 耐疵 with resistance.
[0073]
　Figure 2 is a sample of the cross-sectional TEM observation of Table 1 symbol (4), to identify parts of the quasi-crystal phase, shows an electron beam diffraction image of the part. As shown in FIG. 2, since it was possible to obtain a radial positive decagonal electron beam diffraction image due to the icosahedral structure, this sample was confirmed that it is precipitated quasicrystalline phase.
[0074]
　Incidentally, disclosure of Japanese Patent Application No. 2015-191855 its entirety is incorporated herein by reference.
　All documents described herein, patent applications, and technical standards, each individual publication, patent application, and that the technical specification is incorporated by reference to the same extent as if marked specifically and individually, It incorporated by reference herein.

claims

[Claim 1]And a metallized layer disposed on the surface of the the steel steel, the metal coating layer, a particle diameter 5 ~ 100 [mu] m, a laminated structure of the metal particles of flat shape having a thickness of 0.5 ~ 30 [mu] m,
　the metal the composition of the coating layer, by mass%, Zn: 11 ~ 80% , Al: 3 ~ 80%, Mg: 8 ~ 45%, Ca: 1 ~ 5%, and satisfies a Zn + Al> Mg,
　the metallization layer organization, a quasi-crystalline phase, MgZn 2 and phase consists of a remaining structure, the quasi-crystalline phase and the MgZn 2 and a total area fraction of the phase 45% or more, the area fraction of the remaining structure is 0 a ~ 55%, the quasi-crystalline phase area fraction of is 20% or more, the MgZn 2 Mg-containing Zn alloy coating steel area fraction of phases is 3% or more.
[Claim 2]
　The content of the Al is in mass%, Mg-containing Zn alloy coating steel according to claim 1 which is 3% or more and less than 13%.
[Claim 3]
　Mg-containing Zn alloy coating steel according to claim 1 or claim 2 having an oxide film having a thickness of 1 nm ~ 1000 nm which covers the surface of the metal particles.
[Claim 4]
　Mg-containing Zn alloy coating steel according to any one of claims 1 to 3 wherein the metal coating layer is a thermal spray coating layer.
[Claim 5]
　The composition of the metal coating layer has a mass%, Y: 0% ~ 3.5 %, La: 0% ~ 3.5%, Ce: 0% ~ 3.5%, Si: 0% ~ 3.5 %, Ti: 0% ~ 0.5 %, Cr: 0% ~ 0.5%, Co: 0% ~ 0.5%, Ni: 0% ~ 0.5%, V: 0% ~ 0.5 %, Nb: 0% ~ 0.5 %, Cu: 0% ~ 0.5%, Sn: 0% ~ 0.5%, Mn: 0% ~ 0.2%, Sr: 0% ~ 0.5 %, Sb: 0% ~ 0.5 %, Pb: 0% ~ 0.5%, C: 0% ~ 0.5%, Fe: 0% ~ 0.5%, and Cd: 0% ~ 0. containing 5% of one or more, and the following formulas (a) and Mg-containing Zn alloy coating steel according to any one of claims 1 to 4 satisfying the following formula (B).
- formula (A): Ca + Y + La + Ce ≦ 3.5%
, formula (B); Ti + Cr + Co + Ni + V + Nb + Cu + Sn + Mn + Sr + Sb + Pb + C + Fe + Cd ≦ 0.5%
　in formulas (A) and formula (B), the chemical symbol shows the content of each element in mass% .