Investigating the Corrosion Behavior of 17-4PH and Stellite 6 Steel Claddings Created by Direct Laser Deposition Process on 17-4PH Steel Substrate

Due to the efficiency of 17-4PH steel in gas turbines and contact with external particles such as dust and foreign objects, physical deposits such as oil vapors will undergo cracks, wear, and chemical corrosion during operation and will be removed from the cycle of use. Part replacement is not cost-effective due to the high cost of raw materials. In this research, the corrosion resistance of 17-4PH steel cladding and stellite6 on 17-4PH steel substrate was investigated by the Tafel polarization test; In the cyclic polarization curve for 17-4PH steel, the direct scan current density is lower than the reverse scan, and positive hysteresis is seen in the cyclic polarization curve. Also the partially formed passive layer is unstable and fragile. In the 17-4PH cladding, the direct scan current density is lower than the reverse scan, and positive hysteresis is observed in the polarization curve. Also the formed passive layer is resistant to the formation of new holes. In the cover of stellite6, according to the shape of this cover, it has high pitting corrosion resistance in this solution; It forms a negative hysteresis curve and its inverse curve is located in a lower current density than the straight curve; Therefore, the corroded areas can repair themselves by forming a passive layer. By examining the results, it was found that the corrosion rate of stellite6 and stainless steel claddings has decreased by 91% and 50% compared to the substrate.