Abstract
This paper presents the results of a study showing how isothermal aging affects the wear properties of Cr-Ni overlay alloy coatings with dispersed NbC particles. High Cr-high Ni coatings, with and without niobium carbides, were deposited on mild steel substrates via plasma transferred arc welding then age-hardened at temperatures from 773 to 1023 K. The precipitation behavior and wear properties of the coating samples were examined using Vickers hardness testing, SEM, TEM, EDX, XRD, and Ohgoshi wear testing. The results showed that isothermal aging significantly improved the hardness and wear resistance of the NbC-dispersed alloy but had little effect on the NbC-free samples. The difference in precipitation behaviors is probably due to the presence of niobium atoms in the alloy matrix, resulting in a continuous precipitation of α' phase.
