Consequences Of Polarization Of Co-Anti-Ni-Industrial Chemicals

EXPERIMENTAL DETAILS
All chemicals used were Merck reagent grade. Solutions were formulated with chromium sulfate (Cr¬2(SO4)3.6H2O) as chromium source in the quantities presented in (Table 1); Solutions were heated to 60°C for three hours during complexation reaction as in [29], and pH was adjusted to 3 units without HCl or NH3 .
Table1- electrolyte and electrodeposition parameter
The coatings were deposited on a 1 x 1.5 cm2 cooper plate sample. Preparation for all specimens was as follow: Firstly, the surface was mechanically polished using different grade emery paper up 600 (to simulate industrial conditions) and then manual and anodically degreased in sodium hydroxide (5% w/v), after having been activated in sulfuric acid (5% w/v) for 2
5 plots the cyclic polarization curves of the of Co-Cr-Ni-Fe alloy coatings in 3.5%NaCl solution.The black arrows next to the forward and reverse anodic branches indicate the potential scan directions. Negative hysteresis is said to occur when the current density of the reverse scan is less than that of the forward scan whereas positive hysteresis is said to occur when the reverse scan exceeds the forward scan [33,34]. The negative hysteresis in the reverse scan of the cyclic polarization curve (Fig.5) indicates that the Co-Cr-Ni-Fe alloy is not susceptible to localized corrosion, and that the passive film repairs
As it can be seen, in this table the electrical resistance of Pulsed current electrodiposited alloy coatings without additive is the highest and has the highest values of Rct implying the better anti-corrosion ability.
Although the sample wich electrodeposited from PPG bath with direct current is the highest and has the highest values of Rct implying the better anti-corrosion ability than the sample without additives of PPG in bath.
The EIS results also confirm that the Pulsed current electrodiposited alloy coatings elevate the anti-corrosion performance of samples consistent with the results of the potentiodynamic polarisation technique.

Conclusions
1) CrCoNiFe alloy coating structure type (FCC) and the crystallite size determined by Scherrer formula is 38 nm.

2) Excellent resistance to being pitted against aggressive chloride ions .

3) Good adhesion to the substrate and the coating thickness is 20 microns in optimum conditions were obtained .

4) Propylene glycol and saccharin additives to be effective to reduce the HER reaction and thus increase the quality and smooth surface coating with plating method with direct current