Electrodeposition and tribological behavior of amorphous chromium-alumina composite coatings

The amorphous chromium-alumina (a-Cr-Al2O3) composite coatings with thickness of 50 μm were electrodeposited from Cr(III) electrolytes containing Al2O3 particles and Al3+. The effects of Al3+ on the dispersibility and Zeta potential of Al2O3 particles in electrotyles were investigated. It was found that the Al3+ promotes the Al2O3 particles to uniformly disperse in the Cr coatings. Tribological behavior of a-Cr-Al2O3 composite coatings was studied as compared with amorphous chromium (a-Cr) coatings electrodeposited from single Cr(III) electrolytes. The results demonstrate that the introduction of Al2O3 particles significantly improves the tribological performance of a-Cr coatings.