Solid Particle Erosion of HVOF Sprayed (35WC-Co/NiCrBSi Coating at Higher Temperature

Abstract

High temperature erosion is generally encountered in boiler components in thermal power plants, especially in superheater, reheater, and economisers parts, where in fly ash particles attack the boiler components and cause high temperature erosion phenomena. It is known as fly ash erosion. The erosion behavior at elevated temperature is much different from that of room temperature erosion as there would be a higher erosion loss encountered at higher temperature due to higher plastic deformation as well as weak bonding between grains/particles. It is therefore imperative to study in depth the erosion wear assessment both at room temperature as well as at elevated temperature in the laboratory. This paper investigates thermal sprayed coatings produced by the high velocity oxygen fuel (HVOF) to improve the material performance under such conditions. 35 WC-NiCrBSi HVOF sprayed coatings were tested under high temperature (up to 700℃) erosion by means of an apparatus that simulated real conditions. The results showed that under these tests conditions the 35WC-NiCrBSi coating worn about 1.4 times less than bare SS-310 steel at room temperature and 300℃ Temperature, while at 700℃ C 35WC-NiCrBSi worns about 2 times higher than bare SS-310 steel at 90℃ impact angle. This shows 35WC-NiCrBSi erosion sensitivity at higher temperature.