Electrochemical behavior of Yttria stabilized thermal barrier coating on mild steel in artificial sea water

The plasma sprayed yttria stabilized thermal barrier coating electrochemical behavior was investigated in artificial sea water by linear polarization resistance (lpr),open circuit potential,and electrochemical impedance spectroscopy (eis) methods at room temperature. thermal properties of applied coating after 600 hours exposure in 3.5% nacl solution demonstrated 0.5% weight loss at about constant heat flow rate of 1 watt/gm upto 400°c followed by regain in weight at 600°c due to endothermic reaction. the initial weight loss at constant heat flow was attributed to stabilization of coating the electrochemical analysis revealed that the open circuit potential became positive after 600 hours compared to 0 hour with decrease in polarization resistance. the 28% decrease in charge density after 600 hours exposure in 3.5% nacl solution was in support to decrease in polarization resistance. the decrease in charge transfer resistance was attributed to the ingress of chloride ions at the coating metal interface and localized corrosion reactions at the oxide film. © pakistan academy of sciences.