Enhancement of Corrosion and Wear Resistance of Ni–P Coatings Stems from the Synergistic Effects of Cr<sub>3</sub>C<sub>2</sub> and Heat Treatment
Quangang Chen, Shijun Xu, Yi He, Siming Yan, Yi Fan, Zhiyuan Li, Huilian Zhou, Hongjie Li, Kaijun Wei, Xianmin Gong, Xingtao Cheng
Abstract
This study describes the preparation of Ni–P–Cr 3 C 2 composite coatings using pulsed electrodeposition, with varying Cr 3 C 2 concentrations (0, 1, 2, 3, 4, and 5 g/L). Subsequently, the Ni–P–Cr 3 C 2 composite coatings are heat-treated at different temperatures (200, 400, and 600 °C) using the characteristic of Cr 3 C 2 oxidizing to Cr 2 O 3 at high temperatures. The Ni–P coatings, Ni–P–Cr 3 C 2 composite coatings, and heat-treated-state Ni–P–Cr 3 C 2 composite coatings are compared and discussed. The results show that the hardness, wear resistance, and corrosion resistance of the composite coatings are optimized when the Cr 3 C 2 content is 3 g/L and the heat-treatment temperature is 400 °C. This is due to the presence of oxides such as Cr 2 O 3 on the surface of the composite coatings after heat treatment at 400 °C. By efficiently enhancing the coating’s densification to the substrate, these oxides raise the composite coating’s resistance to corrosion and wear. The Ni–P–Cr 3 C 2 composite coating in its heat-treated makeup at 400 °C is found to have long-term corrosion resistance in the 3.5 wt % NaCl solution immersion test. This study provides a new idea in the field of corrosion.