Characterization of the Cr-C/Si 3 N 4 Composite Coatings Electroplated from a Trivalent Chromium Bath

Abstract Cr-C/Si 3 N 4 composite coatings are obtained by electrodeposition under DC conditions from a trivalent chromium plating bath containing suspended Si 3 N 4 nanoparticles. The influences of plating parameters including Si 3 N 4 concentration in the plating bath and current density on the coating composition, deposition rate, morphology, surface roughness, micro-hardness and wear behavior of electrodeposited Cr-C/Si 3 N 4 composite coatings are evaluated and compared with that of electrodeposited Cr-C coating. Our study reveals that Si 3 N 4 particles can be successfully codeposited and uniformed distributed in the electrodeposited Cr-C matrix. The maximum level of incorporation of Si 3 N 4 particles, about 17.22 vol%, is obtained at a bath loading of 5 g L −1 and at a current density of 20 A dm −2 . Due to enhanced dispersion strengthening effect, the incorporation of Si 3 N 4 particles increases the microhardness of the coatings and significantly increases the wear resistance of the coatings.