ELECTRODEPOSITED CR-AL2O3 COMPOSITE COATING FOR WEAR-RESISTANCE

The co-deposition of Al2O3 particles with chromium is possible when a rare earth element is added into a conventional hexavalent chromium ba th. The effect of various plating variables on the Al2O3 content of th e coating was studied. When the coating contains about 0.7-1.0 wt.% of Al2O3, the hardness of the composite coating has the highest value of about 1300 Hv, and the wear resistance of this coating is increased b y two to six times as compared with that of chromium coating. The cath ode polarization curves show that the rare earth affects the electrode process of chromium deposition.