The Effect of Heat Treatment on the Corrosion Resistance, Mechanical Properties and Wear Resistance of Cr?C Coatings and Cr?C/Al₂O₃ Composite Coatings Electrodeposited on Low Carbon Steel

摘要

In order to enhance the corrosion resistance, mechanical properties and wear resistance of Cr?C thinfilms, Cr?C/Al2O3 composite coating is electrodeposited from the Cr(III) plating bath containingAl2O3 particles in this study. The Cr?C/Al2O3 composite coating has the best corrosion resistancewhich icorr is approximately at 2.84 × 10-7 A/dm2, but the corrosion resistance will reduce with anincrease of heating temperature due to the formation of cracks within Cr?C/Al2O3 composite coatings.The effect of heat treatment on the mechanical properties and tribological behavior of Cr?C coatingand Cr?C/Al2O3 composite coating is examined. The experimental results show that the hardness ofCr?C coating and Cr?C/Al2O3 composite coating increased with a heat treatment process due to theprecipitation of chromium carbide and chromium oxide. The incorporation of Al2O3 particles into theCr?C matrix can significantly enhance the micro-hardness and reduce the wear rate of Cr?C/Al2O3composite coating as compared to that of Cr?C coating. The highest micro-hardness of Cr?C/Al2O3composite coatings (22.85 GPa) is achieved after the coatings heated at 600 ℃. The co-deposition ofAl2O3 particles within the Cr?C deposits will significantly improve the wear resistance of coatings andreduces the wear weight loss. The lowest specific wear rate (8.8 × 10-7 mm3/Nm) was obtained for theCr?C/Al2O3 composite coatings heat treated at 200 ℃.