The Electroless Monolayer and Duplex Ni-B and Ni-P Coatings for 316L Stainless Steel in Synergistic Combination of Mechanical (Wear) and Chemical (Corrosion) Processes

Abstract

Conventional processes are performed to improve the low hardness and low wear resistance properties of 316L steel, but these processes generally decrease the corrosion resistance. Electroless nickel alloy coatings provide a hard, wear-resistant, and corrosion-resistant surface. Thus, the present study aims to investigate the wear, corrosion, and tribocorrosion behaviors of monolayer and duplex coatings with nickel-boron (Ni-B) and nickel-phospore (Ni-P) on 316L steel in comparison with 316L steel in dry sliding and 0.9 wt% NaCl solution environments. It is determined that the coatings have a mixture of crystal and amorphous structures, the interfaces on the 316L are uniform, and the compatibility between the layers is good. The Ni-B, Ni-P/Ni-B, and Ni-B/Ni-P coatings are 2.3, 2.06, and 1.6 times as hard as the 316L, respectively. The wear rates of Ni-B, Ni-P/Ni-B, and Ni-B/Ni-P coatings show decrease by 99.3%, 92.5%, and 99.1% in the dry-sliding condition and by 98.5%, 30.1%, and 19.1% in the tribocorrosion condition compared with that of 316L, respectively. It is observed that the monolayer Ni-B coating exhibits superior hardness, a higher contact angle, low electrical conductivity, and better tribological performance in both dry sliding and tribocorrosion conditions compared to the 316L and duplex coatings.