The study of Cr₃C₂-25NiCr and 35WC-Co/65NiCrBSi-based HVOF coatings for high-temperature erosion resistance application

Abstract

This work concerns a technique to produce thermal sprayed coatings using HVOF (highvelocity oxy-fuel) method as it is a widely used application in high-temperature erosion and corrosion environment. Two types of hard coatings Cr 3 C 2 -25NiCr and 35WC-Co/65NiCrBSi were sprayed on an SS-347 steel substrate. The erosion tests were done using hightemperature jet erosion set up to study the effect of velocity, temperature and impact angles on the coatings produced. The surface morphology of the samples was characterized using 3D laser confocal microscopy, light microscopy, scanning electron microscopy with EDAX and X-ray diffraction. Microhardness, porosity level and roughness parameters were evaluated to infer a probable mechanism of material removal. The Cr 3 C 2 -25NiCr coating exhibited ∼3.3 times higher erosion resistance than 35WC-Co/65NiCrBSi coating at 90°and 30°impact angles. SEM and 3D laser confocal images on the eroded surface of the coatings reveal the combination of ductile and brittle fracture of coating.

High-Temperature Erosion of SiC-NiCrAlY/Cr3C2-NiCr Coating

“…However, these materials show operation limits at temperatures of 450-550 • C and 800-900 • C, respectively [4][5][6][7]. For this reason, the use of high-temperature alloys that are Fe-based, Ni-based, and MCrAlY (M=Ni, Co or NiCo), and the mixture of these alloys with different ceramics and cermets such as TiC-NiMo, CrB, Cr 3 C 2 , WC-Co, etc., have been proposed [4,[8][9][10][11][12]. The MCrAlY alloy family is attractive because these alloys are used in thermal barriers and for protection against high-temperature oxidation corrosion up to 1000 • C [13][14][15], and recently as a binder phase for cermet materials subjected to high-temperature erosion investigations [16][17][18].…”