Microsliding wear behaviour of HVOF sprayed conventional and nanostructured WC–12Co coatings at elevated temperatures

Abstract

Conventional and nanostructured WC–12Co coatings were deposited on 1Cr18Ni9Ti substrate using high velocity oxy-fuel spraying. The surface roughness and microhardness of as sprayed coatings were measured, while the phase compositions and microstructures of WC–12Co feedstock powders and corresponding coatings were respectively analysed by means of X-ray diffraction and scanning electron microscopy. Moreover, the microsliding wear behaviour of both coatings sliding against Si₃N₄ ball from room temperature to 500°C was evaluated under unlubricated condition with an oscillating SRV tribotester. Results reveal that nanostructured WC–12Co coating not only had better wear-resistance than the conventional WC–12Co coating but also led to reduced wear of the Si₃N₄ counterpart under the same test condition, which could be attributed to the fine microstructure and improved mechanical properties of the nanostructured coating. The detailed wear mechanisms for both coatings have also been discussed.