Claims:Claims:
1. A sacrificial anode for cathodic protection comprising:
Phosphorus 1.5 to 8.0 wt%, carbon 2.7-3.1 wt%, manganese 0.85-1.10 wt.%, silicon 2.4-2.8 wt.%, sulphur 0.025-0.04 wt.%, inevitable impurities and Fe balance composition, and blow holes over its surfaces.
2. The sacrificial anode as claimed in claim 1, wherein driving voltage (V) for sacrificial behaviour of the sacrificial anode coupled to a steel in soil/water/sea water atmosphere is (0.10 – 0.3) V.
3. The sacrificial anode as claimed in claim 2, wherein the steel is rebar.
4. The sacrificial anode as claimed in claim 3, wherein the driving voltage (V) for sacrificial behaviour of the sacrificial anode coupled to the rebar in Reinforced Cement Concrete is > 0.10 V.
5. The sacrificial anode as claimed in claim 1, wherein corrosion rate of the sacrificial anode coupled to steel in soil/water/sea water/RCC atmosphere is (0.4 – 1.2) mm/year.
4. The sacrificial anode as claimed in claim 1, wherein electrochemical capacity of the sacrificial anode in soil /water/sea water/RCC atmosphere is (290 - 450) Ah/Kg.
5. The sacrificial anode as claimed in claim 1, wherein sacrificial anode to soil /water/sea water resistance is 590 - 3000 Ohm.
, Description:FIELD OF THE DISCLOSURE
The present disclosure relates to a sacrificial anode. More particularly the disclosure relates to anode for cathodic protection of steel at various locations.
BACKGROUND OF THE DISCLOSURE
Conventionally zinc, aluminium and magnesium based alloys are used as to provided sacrificial anode to underground pipelines.

When the zinc based sacrificial anodes are used, they tend to contaminate the local water bodies by solubilized zinc which may cause ecological damage and can also contaminate the food chain if the zinc level in water rises beyond 5µg/L.

When the aluminium based sacrificial anodes are used, they tend to form passive oxide film on pure and unalloyed aluminium (A.H. Al-Saffar et al.). This restricts their use as sacrificial anodes. Hence, in order to make it suitable for cathodic protection they are often alloyed with mercury (Hg), indium (In), tin (Sn) and titanium (Ti). However, aluminium sacrificial anode is only limited to marine application.

Magnesium based sacrificial anodes have low current efficiency of about 50% which has been reported to be due to enhanced corrosion rate of the anode. As a result, in order to increase the efficiency of magnesium sacrificial anodes, they are alloyed with aluminium, zinc and manganese that add up to the cost.
Further, the cathodic protection based on Mg, Zn and Al alloys are environmentally hazardous and they tend to contaminate the environment. Moreover, Al, Zn and Mg are costly metals.
OBJECTS OF THE DISCLOSURE
In view of the foregoing limitations inherent in the prior-art, it is an object of the disclosure to propose a product that may give the cathodic protection to steel in corrosive environment.
The other object of the disclosure is to propose the product that is economical against conventionally used material for such applications.
SUMMARY OF THE DISCLOSURE
The disclosure provides a sacrificial anode for cathodic protection comprising phosphorus 1.5- 8 wt.% carbon 2.7-3.1 wt%, manganese 0.85-1.10 wt.%, silicon 2.4-2.8 wt.%, sulphur 0.025-0.04 wt.%, inevitable impurities and Fe as balance, and blow holes generated over its surfaces.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figs. 1(a)-1e Illustrates SEM micrograph of samples with varied compositions in accordance with an exemplary embodiment of the disclosure.
Fig. 2 Illustrates the XRD pattern for the samples disclosed in Figs. 1a-1e.
Fig. 3a-3c Illustrates the secondary electron SEM micrograph of the fracture surface for the samples disclosed in Figs 1(a)-1(c).
Fig. 4a Illustrates EDS area mapping for the samples of Fig. 1a with 1.5wt.% P corresponding to Fig 3(a).
Fig. 4b Illustrates EDS area mapping for the samples of Fig. 1b with 3.5 wt.% P corresponding to Fig 3(b).
Fig. 4c Illustrates EDS area mapping for the samples of FIG. 1c with 8.0 wt. % P corresponding to Fig 3(c).
Fig. 5 Illustrates back scattered electron (BSE) SEM micrograph of sacrificial anodes samples with (a) 1.5 wt.% P, (b) 3.5 wt.% P and (c) 8.0 wt.% P.
Fig. 6 Shows presence of pearlitic colonies in the matrix for sacrificial anode samples with (a) 1.5 wt % P, (b) 3.5 wt % P and (c) 8.0 wt % P.
Fig. 7 Shows experimental setup for real time potential and current measurement between anode and cathode.
Fig. 8 Shows surface appearance of the mild steel, sacrificial anode with 1.5 wt.% P, 3.5 wt.% P and 8.0 wt.% P and magnesium samples after exposing the couple for a month in soil.
Fig. 9A Illustrates morphology of corrosion products on (a) mild steel coupled to 1.5 wt. % P, (b) mild steel coupled to magnesium, (c) 1.5 wt. % P and (d) magnesium after exposing the couple for a month in soil.
Fig. 9B Illustrates the morphology of corrosion products on (a) mild steel coupled to 3.5 wt.% P, (b) mild steel coupled to 8.0 wt.% P, (c) 3.5 wt.% P and (d) 8.0 wt.% P after exposing the couple for a month in soil in accordance with one of the embodiment of the disclosure.
Fig. 10 Illustrates the FTIR spectra for the corrosion products of pig iron samples (1.5 wt.% P, 3.5 wt.% P and 8.0 wt.% P) after one month of the exposure to soil in accordance with one of the embodiment of the disclosure.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE DISCLOSURE
In accordance with an embodiment of the invention a sacrificial anode for cathodic protection is described. The sacrificial anode comprises Phosphorus 1.5 to 8.0 wt%, carbon 2.7-3.1 wt%, manganese 0.85-1.10 wt.%, silicon 2.4-2.8 wt.%, sulphur 0.025-0.04 wt.%, inevitable impurities and Fe balance composition, and blow holes over its surfaces.
The said composition of the sample can be obtained conventionally through blast furnace route or through electric arc furnace. The molten metal obtained through the said route can be further refined as per the composition defined and casted and later transformed into the sacrificial anode.
The high phosphorus content (1.5-8.0 wt %) for the said pig iron is maintained so as to make it behave as a sacrificial anode for cathodic protection of steel and / OR other engineering materials, due to enrichment of the surface with phosphorus as iron phosphate hydrate (FePO4.2H2O) under immersed condition. The layer thus formed is highly unstable in nature and undergoes continuous dissolution in the soil submerged condition that could help in supplying electrons required for cathodic reaction on the surface of steel, which is to be protected cathodically.
The Carbon (2.7-3.1 wt%) forms graphite within the sacrificial anode which acts anodic to the rest of the material. It further helps in improving the efficiency of sacrificial anode material by promoting the formation of local galvanic cells on microscopic level.
Presence of silicon (2.4-2.8 wt %) results in graphitization and forms graphite flakes in the sacrificial anode matrix. Also presence of Si results in formation of inclusions of SiO2 along with unreduced FeO. However, effect of silicon is more on the graphitization, as seen in the present sacrificial anode. Low silicon content is beneficial from the point of anodic nature of the pig iron since low content of Si does not allow any protective layer formation.
Manganese (0.85-1.10 wt.%) Mn is present in solid solution for sacrificial anode material and in presence of Sulphur it forms Manganese sulphide (MnS) inclusions which nucleate generally at the grain boundaries and act nobler compared to the sacrificial anode. These inclusions can form micro galvanic cells within the cast iron material resulting in higher corrosion rate and thereby increasing the sacrificial anode property of the material.
Following samples with various compositions were tried, mentioned in below Table 1.

Table 1
Sample C (wt.%) Mn (wt.%) Si (wt.%) P (wt.%) Fe (wt.%)
Sample 1

Sample 2

Sample 3 2.70

3.10

2.90 0.85

0.80

1.10 2.40

2.80

2.50 1.50

3.50

8.00 balance

balance

balance
Sample 4 of mild steel for comparison is also tried with following composition carbon 0.15 wt.%, silicon 0.1 wt.%, sulphur 0.05 wt.%, Mn 0.2%, P 0.04% Fe balance.
Figure 1 depicts the SEM micrographs of the samples of sacrificial anode (with 1.5 wt.% P, 3.5 wt.% P and 8.0 wt.% P), mild steel and magnesium samples. Sharp graphite flakes could be observed in the microstructure of all the samples along with pearlite colonies entrapped in between a layered region of iron phosphide (Fig 1(a-c)). Presence of shallow voids could also be observed on the surface of samples which could have formed as a result of casting practice. The microstructure of magnesium shows grains and grain boundaries with absence of any second phase particles (Fig 1d). On the other hand, the microstructure of mild steel shows the presence of ferrite and pearlite (Fig 1e). The XRD peaks for both mild steel and pig iron samples shows the existence of bcc iron. Moreover, the samples 2 and 3 with higher phosphorus content (3.5 wt.% P and 8 wt. % P) also shows the existence of a separate peak for iron phosphorus, which is absent in case of mild steel sample 4 (Fig 2). Also, the peak for commercially pure magnesium confirms the existence of hcp phase.
Manganese (0.85 – 1.10 wt%) and sulphur (0.025-0.04 wt%) present in the samples of the sacrificial anode (Fig 3) shows the fracture surface of sample 1, sample 2 and sample 3. It is evident from the figure that all the three different compositions of sacrificial anode depict brittle fracture. In order to confirm the presence Mn, S and P along the broken ligaments, EDS area mapping is performed at the fracture surface of sample 1, 2 and 3as illustrated in Fig 4(a-c). Segregation of Mn, S and P are shown along the broken ligaments. It suggests that these ligaments are very active regions since Mn along with S would act as anodic regions, allowing pitting to initiate along these zones. It has also been reported that presence of MnS inclusion plays a leading role in enhancing the initial corrosion rate in chloride containing environment as Cl ions get adsorbed and accumulated around MnS inclusions resulting in localized corrosion. Here also enriched S and Mn ligaments would behave similarly. Moreover, P enrichment along these ligaments also accelerates the corrosion process.
Fig. 5 illustrates the presence of inclusions (oxides, sulphides, slag inclusions) in the matrix of samples 1, 2 and 3 of sacrificial anode. The compositions of various inclusions (in wt.%) are listed in Table 2. Presence of inclusions in high phosphorus iron under immersed condition has a detrimental effect on its corrosion resistance as it hinders the formation of stable phosphate layer on the surface.
Table 2
Elements C O Na Al Si S Ca Mn P Fe
Sample1
Sample2
Sample3 46.01
-
- 26.21
7.26
1.69 1.09
-
- 8.33
7.13
- 1.23
2.83
2.97 0.27
0.02
0.08 0.30
-
- 0.17
0.52
0.64 -
-
0.15 16.39
82.24
94.47
In case of high phosphorus pig iron under immersed condition in soil, the initial corrosion rate is high due to enrichment of the surface with higher phosphorus content at the metal/scale interface which eventually results in formation of ionic phosphate at the surface. Based on thermodynamics, the free energy for the formation of FePO4 and H3PO4 at 298.15 K and 1 bar pressure are,
??G?_(?FePO?_4 )=-1657.5 KJ/mol
?G_(H_3 ?PO?_4 )=-1119.2 KJ/mol
Hence, the formation of iron phosphate is much favoured at the rust/metal interface which results in further corrosion of the surface.
The said sacrificial anode comprises blow holes on its surfaces. This presence of blow holes is a result of impurities and entrapped inclusions which may also accelerate the localized attack due to the presence of chloride ions present in the soil and enhance the corrosion rate.
Fig 6 depicts the presence of pearlitic colonies in the matrix of sample 1, 2 and 3 enclosed in thin layered region of phosphide. The higher volume fraction of pearlite and presence of non-metallic inclusions in the iron matrix could result in higher corrosion rate of iron matrix under complete immersed condition due to galvanic couple formation. The interfaces between the iron matrix and the entrapped inclusions have also been found to behave as an ideal potential site for pitting corrosion.
The Driving voltage (V) for sacrificial behaviour of the sacrificial anode with respect to steel in soil, water and sea atmosphere is (0.10 – 0.3) V.
In an embodiment, steel can be rebar, where the sacrificial anode may be used to protect rebars in reinforced cement concrete where zinc and magnesium anodes have limited possibility of use due to high self-corrosion rate.
The driving voltage (V) for sacrificial behaviour of the sacrificial anode coupled to the rebar in Reinforced Cement Concrete atmosphere is > 0.10 V.
In accordance with an exemplary embodiment of the invention, the driving voltage for sample 1, 2 and 3 with respect to sample 4, mild steel, is 0.10 – 0.3, 0.15 – 0.27 V and 0.2 – 0.3 respectively.
The electrochemical capacity of the sacrificial anode in soil/water/sea water/RCC atmosphere is (290 - 450) Ah/Kg.
In accordance with an exemplary embodiment of the invention, the electrochemical capacity for sample 1, 2 and 3 is 290 - 450 Ah/Kg, 280 – 300 Ah/Kg and 275 – 290Ah/Kg respectively.
The sacrificial anode to soil resistance for the samples 1, 2 and 3 acting as an anode is (590 - 3000) Ohm.
Further, the obtained sacrificial anode has the corrosion rate when coupled to steel in soil/water/sea water/RCC atmosphere for the sacrificial anode is (0.4 – 1.2) mm/year.
For the samples 1, 2 and 3 the corrosion rate is (0.4 – 0.7) mm/year, (0.9 – 1.1) mm/year and (1.0 – 1.2) mm/year respectively.
Advantages:
The obtained pig iron provides the cathodic protection to the underground pipelines.
Further, the sacrificial anode is much cheaper as compared to the available sacrificial anodes in the market
The obtained pig iron is environment friendly while providing the cathodic protection.
Experimental Analysis
The sacrificial anode for cathodic protection is based on the principle of supplying electrons to the metal structure to be protected. Sacrificial anode type cathodic protection system provides cathodic current by galvanic corrosion. Current is generated by metallically connecting the structure to be protected to a metal/alloy that is electrochemically more active than the structure to be protected.
An experiment was performed to analyse the performance of sacrificial anode during cathodic protection of steel plates. It was then compared with magnesium rod that was also used as sacrificial anode to cathodically protect the same composition of steel plates.
The dimensions of the various materials used in the experiment is as shown below-
Mild Steel plates – 3 cm X 3.2 cm X 1 cm
sacrificial anode (sample 1, 2 & 3) – 2 cm X 2 cm X 1 cm
Magnesium rod – Length- 4.8 cm, diameter- 2 cm
The chemical compositions of the various materials used (in wt.%) in the experiment is shown below
Mild steel with sacrificial anode
Materials C Mn Si P Fe
Mild steel
sample1
sample2
sample3 0.17
2.70
3.10
2.90 0.68
0.85
0.80
1.10 0.28
2.40
2.80
2.50 0.02
1.50
3.50
8.00 balance
balance
balance
balance

Mild steel with magnesium rod
Element C Mn Si P Fe
Mild Steel 0.17 0.68 0.28 0.02 Balance
Magnesium anode composition Mg-99.86 Fe-0.13 Si-0.01
In the first setup, all the three samples (1,2 and 3) were connected to the steel plate, which was to be protected, using a copper wire.
In the second setup, the magnesium rod was connected to the similar steel plate of same composition.
The copper wire at the point of contact with the steel plate and the sacrificial anodes were carefully insulated using lacquering. The insulation was done in order to prevent the galvanic coupling that could form between steel plate and the copper wire resulting in the corrosion of steel plate. Another purpose of insulation was to prevent any current leakage.
All the samples and magnesium anodes were surrounded by backfill. The purpose of backfill is to improve the electrical contact between the sacrificial anode and the surrounding soil. The composition of backfill used is:
75% Gypsum (CaSO4.2H2O)
20% Bentonite clay
5% Sodium sulphate (Na2SO4)
All the setups were buried under the soil separately for 1 month. They were kept at appreciable distance in order to ensure no stray current effect between the two setups. Potential and current were measured at real time with the help of program installed on Arduino Uno software.
Composition of soil (shown in Table 4) was analysed using ion chromatography. The pH, moisture content and resistivity of the soil were determined based on ASTM G51-95, ASTM D4959-16 and ASTM G57-06 respectively.
Table 4
Parameters pH Moisture content Na+ (mg/L) Mg2+(mg/L) Ca2+(mg/L) Cl-(mg/L) NO3-(mg/L) F-(mg/L) SO42-(mg/L)
Value 8.7 23.4 % 11.006 0.639 3.864 13.970 0.317 0.412 0.496
After the completion of 1 month of experiment, the corrosion products were cleaned using the following chemicals based on ASTM G1-03.
For sacrificial anode and steel:
1000 ml hydrochloric acid,
20 g antimony trioxide (Sb2O3),
50 g stannous chloride (SnCl2)
For Magnesium:
200 g chromium trioxide (CrO3),
10 g silver nitrate (AgNO3)
20 g barium nitrate (Ba(NO3)2) and
Reagent water to make 1000 ml.
The experimental setup for real time potential and current measurement is shown in Fig. 7.
After one month of experiment the samples were taken out from the soil. It can be seen that in case of galvanically coupled sacrificial anode the samples and mild steel (Fig. 8(a-c)), the surface of sacrificial anode samples for all the compositions of phosphorus appears to be more corroded as compared to mild steel. The surface of the steel plate faced towards the sacrificial anode samples was not corroded much and similar behaviour was seen in case of steel plate connected to the magnesium rod. However, as compared to sacrificial anode, magnesium anode was aggressively corroded (Fig. 8d) which signifies that sacrificial anode can be used for longer period. On the other hand, the surface of bare mild steel (Fig. 8e) without any protection could be seen to be corroded severely as compared to the mild streel plates coupled to sacrificial anode samples. Thus, based on the macrographic observation it could be confirmed that pig iron has the ability to minimize the corrosion rate of mild steel if coupled galvanically in soil.
Figs. 9A and 9B depicts the morphology of the corrosion products formed on the surface of mild steel plates and the sacrificial anodes after one month of the exposure in the soil. The corrosion products on mild steel plates coupled to the sample 1 shows the presence of flower like morphology which confirms the presence of lepidocrocite (?-FeOOH) phase whereas the corrosion products on the mild steel plates coupled to sample 2 and sample 3 shows the appearance of cotton ball like structure which suggest the presence of goethite (a-FeOOH) as the primary phase. ?-FeOOH is an electrochemically active phase whereas a-FeOOH is a non-active phase and stable form of rust. Presence of a-FeOOH on the surface of mild steel samples coupled to pig iron could be beneficial in lowering the corrosion rate. On the other hand, the surface of 8P sacrificial anode sample shows the appearance of deep pits. Also, selective dissolution of the phosphide layered region could be observed.
The rust formed on the surface of all the three different sacrificial anode samples under the soil has been characterized with the help of FTIR which confirms the presence of soluble iron phosphate hydrate (Fig 10). Also, the absence of magnetite (Fe3O4) and d-FeOOH from the rust of sacrificial anode samples implies that the rust is not protective in nature.
Thus, based on the above experiments it can be concluded that sacrificial anode could be a potential candidate as a sacrificial anode during cathodic protection of steel plates and there could be a scope to use it industrially since it will be much cheaper options as compared to magnesium.
It can also be proven from the electrochemical experimental analysis that sacrificial anode sample is more active as compared to mild steel during immersed condition. Also, if the oxygen content is lowered in the solution with the help of nitrogen purging, the OCP drops significantly.
The electrochemical tests were carried out in Parstat 2263 system in a Flat bottom cell consisting of a specimen, a saturated calomel electrode with saturated calomel (+0.2444 V versus SHE) and platinum wire mesh as the working, reference and counter electrodes, respectively. Nitrogen purging was done to deaerate the solution.
In a 3.5% NaCl solution after 1 hr of stabilization, the OCP variation for the three different pig iron samples, mild steel and magnesium without and with nitrogen purging are listed in Table 5. It could be seen that in a deaerated solution with nitrogen purging, the sacrificial anode samples become more active. Thus, reducing the oxygen content of the environment where the sacrificial anode is exposed, restricts the formation of a stable phosphate layer on the surface. On the other hand, it could also be seen that, deaerating the solution does not have any effect in lowering the OCP of Mg samples.
Table 5
Without N2 purging With N2 purging
Materials OCP (V) OCP (V)

Mild steel

sample 1

sample 2

sample 3

Magnesium

- 0.697

- 0.715

- 0.743

- 0.736

- 1.614
-

- 0.767

- 0.766

- 0.773

- 1.603

Formulas used during the calculation are given as follows;
The output current is given by ohm’s law
I = V/R
Where,
I - output current
V -Driving voltage
R- Total resistance of a vertically installed anode in the electrolyte
The resistivity of the soil was computed using Wenner four pin method used in laboratory scale with probe spacing of (a=0.25 cm). However, the instrument used in field measurement (A.W. Peabody et al.) has a minimum probe spacing of (A=76.2 cm). So, we introduce a proportionality constant K (=A/a) to the resistivity to replicate the field resistivity condition. Hence, the resistivity of the soil is calculated according to the formulae,
? = 2?aR*K
Where,
K is the proportionality constant (=305)
R is the soil resistance measured from the instrument (=20.01 ?)
The total resistance can be approximated using H. B. Dwight’s equation which is given as:
R=0.00521/L ?[ln?(8L/D)-1]
However, for anode to cathode separation of less than 30 cm, a correction factor of 1.3 is introduced to the total resistance (DNV-RP-B401).
Where,
? is resistivity of soil (O-cm) (for the present soil ? = 9863 O-cm)
L is length of anode (feet)
D is diameter of packaged anode (feet)
The practical electrochemical capacity (Ah/Kg) can be calculated as:
e=Q/?m
Where
Q = total charge transfer (=I (A) × time (hr))
?m = weight loss of anode (Kg)
Table 6: calculation of output current and anode capacity
Sacrificial anode Magnesium sample 1 sample 2 sample 3
Driving voltage (V) 0.78 0.20 0.24 0.26
Anode to soil resistance (ohm) 471 602 602 602
Output current (A) 1.66X10-3 3.32X10-4 3.98X10-4 4.31X10-4
Output current density (A/cm2) 4.5X10-5 2.0X10-5 2.5X10-5 2.7X10-5
Electrochemical capacity (Ah/Kg) (1022-1128) (265-270) (290-297) (275-307)

Note 1- the driving voltage is the potential difference between the sacrificial anode and steel plate when buried under the soil which was measured with the help of Arduino Uno software.
Note 2- in order to calculate the anode to soil resistance, the dimensions of the anode including the backfill are: For Mg anode: L = 0.1574 ft, D = 0.1476 ft and for all the pig iron anodes: L = 0.0921 ft, D = 0.1181 ft.
Note 3: the corrosion rate was determined using the following formula-
Corrosion rate (CR)=(weight loss(g)*8.75*?10?^4)/(alloy density(g/?cm?^3 )*exposed area(?cm?^2 )*time(hr))

Table 7: weight loss measurement
Material Weight loss (g) Corrosion rate (mm/year)
sample 1 (0.8863-0.9013) (0.9481-0.9641)
sample 2 (0.9660-0.9895) (1.0334-1.0585)
sample 3 (1.0112-1.1293) (0.9705-1.2081)
Magnesium (1.0629-1.1668) (2.0621-2.2637)
MS coupled to sample 1 (0.0029-0.0098) (0.0015-0.0052)
MS coupled to sample 2 (0.0059-0.0141) (0.0031-0.0075)
MS coupled to sample 3 (0.0038-0.0072) (0.0020-0.0038)
MS coupled to Mg (0.0009-0.0013) (0.0004-0.0006)
Bare MS (0.1122-0.1294) (0.0598-0.0690)
Thus, the above experiment shows that pig iron remains anodic to mild steel and it didn’t switch to cathode during the entire one month period of the experiment. So it can be used as sacrificial anode for cathodic protection of mild steel. Deaerating the solution with the help of nitrogen purging has resulted in more active behaviour of pig iron samples. Also increase in phosphorus content in pig iron could increase the corrosion rate of pig iron which could supply more electrons to the mild steel during cathodic protection. Moreover, pig iron sacrificial anodes are highly cost effective as compared to magnesium sacrificial anodes.
Claims:
1. A sacrificial anode for cathodic protection comprising:
Phosphorus 1.5 to 8.0 wt%, carbon 2.7-3.1 wt%, manganese 0.85-1.10 wt.%, silicon 2.4-2.8 wt.%, sulphur 0.025-0.04 wt.%, inevitable impurities and Fe balance composition, and blow holes over its surfaces.
2. The sacrificial anode as claimed in claim 1, wherein driving voltage (V) for sacrificial behaviour of the sacrificial anode coupled to a steel in soil/water/sea water atmosphere is (0.10 – 0.3) V.
3. The sacrificial anode as claimed in claim 2, wherein the steel is rebar.
4. The sacrificial anode as claimed in claim 3, wherein the driving voltage (V) for sacrificial behaviour of the sacrificial anode coupled to the rebar in Reinforced Cement Concrete is > 0.10 V.
5. The sacrificial anode as claimed in claim 1, wherein corrosion rate of the sacrificial anode coupled to steel in soil/water/sea water/RCC atmosphere is (0.4 – 1.2) mm/year.
4. The sacrificial anode as claimed in claim 1, wherein electrochemical capacity of the sacrificial anode in soil /water/sea water/RCC atmosphere is (290 - 450) Ah/Kg.
5. The sacrificial anode as claimed in claim 1, wherein sacrificial anode to soil /water/sea water resistance is 590 - 3000 Ohm.