Effect of heat treatment on properties of nickel hard surface alloy deposited by hvof

Abstract

There are numerous industrial applications in which materials are subject simultaneously to high temperature, oxidation, corrosion, and wear leading to accelerated degradation. Some specific industries where these phenomena have been detected are: chemical, waste incineration, power generation, and paper/pulp with typical applications including boilers, cyclones, heat exchangers, and tubing. Previous studies have established some material compositions and microstructures that can resist these environments. In the search for cost effective industrial solutions, surface coating via thermal spraying becomes attractive. However, not all coatings have been successful in the past owing to adhesion problems, porosity, or unsatisfactory resistance to corrosion and erosion. Spray and fused coatings like nickel hard surface alloys are ideally suited for the elevated temperature environment. The present paper studies the effect of heat treatment, carried out using an oxyacetylene flame, on the microstructure, microhardness, erosion wear, and adhesion resistance of a NiCrBSiW alloy, commercially known as Colmonoy 88, deposited on a plain carbon steel using both wire and powder fed high velocity oxyfuel (HVOF) spray processes.