No abstract

No abstract

In this study, to minimize the corrosion rate zinc coatings conditions were optimized using a Box Behnken design combined with response surface methodology. The different electro zinc coatings were obtained by changing three independent variables; the stirring rate (200-600 rpm), temperature of the bath (30-70°C) and the coating time (30-120 min) in 3.5% NaCl solution. The corrosion rate of the obtained zinc coatings was determined using the Tafel polarization method. A quadratic regression equation was derived to predict the responses. The correspondence between the experimental and predicted values ( = 98.55%) demonstrates that the quadratic model was highly significant with 95% confidence levels (α = 0.05). The optimum zinc coating conditions based on the minimization of corrosion rate were; stirring rate 600 rpm, temperature of bath 55°C and a coating time of 50 min for i corr 16.35 μA/cm 2 .

Ni-Co alloy was electrodeposited on high carbon steel (0.8% C) in acidic bath. Corrosion behav ior of uncoated steel and Ni-Co coated was investigated in 3% NaCl. For this purpose, electrochemical methods such as potentiodynamic polarization, linear polarization (LP), chronoamperometry (CA), open circuit potential (OCP) and time dependent (1th, 4th, 24th, 48th and 72nd hour) impedance spectrometry (EIS) measurement were used. Corrosion surfaces of Ni-Co alloy coated and uncoated steels, which were immersed in 3% NaCl solution, after the first day and fifth day was investigated by SEM. As a result, it is con cluded that Ni-Co alloy coated decrease the steel corrosion.