Studies on properties and structure of electrodeposited RE-Ni-W-B-SiC composite coating

A composite coating, containing 1.35 wt.%RE, 5.46 wt.%W, 3.82 wt.%B, 15 wt.%SiC and Ni was electrodeposited on the matrix by use of appropriate bath composition and process parameters. The addition of RE(CeO2) enhanced the hardness and wear resistance of the coating remarkably. The hardness and wear resistance of the coating increase with a rise in heat treatment temperature, and the hardness reaches the optimum value at 400 deg. C, while the coating has the best wear resistance at 500 deg. C. The wearing tests show that the wear resistance of the coating is four to five times as high as that of hard chromium, and the corrosion tests indicate that the corrosion resistance of the coating is superior to that of 1Cr18Ni9Ti stainless steel in various corrosive media, except for nitric acid. X-ray diffraction shows that the 1.35 wt.%RE-5.46 wt.%W-3.82 wt.%B-15 wt.%SiC-Ni as-deposited composite coating is mainly amorphous, except a few Ni, W, CeO2, B and SiC phases