The effect of impingement angle on erosion wear characteristics of HVOF sprayed WC-Ni and WC-Cr₃C₂-Ni cermet composite coatings

Abstract

The present study investigated the erosion wear behavior of WC-Ni and WC-Cr 3 C 2 -Ni cermet coatings deposited by high velocity oxy-fuel (HVOF) spray process on the substrate of 1Cr18Ni9Ti stainless steel. Microstructures and morphologies of the coatings were examined using SEM images, and x-ray diffractometer was used to analyze the phase composition of the powder and the coatings. The erosion test was carried out using home-made jet rig. In order to better fit the research background of this study, the erodent used for erosion was taken from the Yellow River, China. The coating is well combined with the substrate; and WC-Cr 3 C 2 -Ni coating consists of WC, Cr 3 C 2 and Ni phases, WC-Ni coating consists of WC, W 2 C and Ni phases. Some mechanical properties of the two coatings were compared, WC-Cr 3 C 2 -Ni coatings have higher hardness to be compared with WC-Ni ones due to a lower binder content; and the elasticity modulus and nano-hardness values of the WC-Cr 3 C 2 -Ni coating are higher than that of the WC-Ni coating. The relationship between the wear performance of the coatings and impingement angle was obtained; and the erosion resistance of the coatings was analyzed. It was observed that WC-Cr 3 C 2 -Ni cermet coating exhibits higher erosion resistance under all testing conditions as compared with the WC-Ni cermet coating and 1Cr18Ni9Ti stainless steel. The results show that the erosion mechanism at low angle is mainly cutting, while erosion pits dominate at high angle for the coatings, moreover, plastic deformation could be observed in the case of the binder depletion and cracking found place. and the erosion mechanisms of the 1Cr18Ni9Ti stainless steel are mainly cutting and plastic deformation at low angle and high angle, respectively.

Erosive and corrosive wear performance and characterization studies of plasma‐sprayed WC/Cr 3 C 2 coating on SS316

“…The major mechanism of erosion is plastic deformation and fatigue damage caused by the repetitive impact of impingement particles at a 90° impingement angle. The particles cannot cut the bonding phase due to the vertical impact; the bonding phase wears out due to continuous erodent impaction; cracks in the binder occur along the impingement periphery and in the hard and binder boundary phases; the loss of the bond strength phase leads to successive spallation of loose carbide particles; and the loss of the bonding phase leads to subsequent spallation of free‐standing carbide particles 34 . The formation and propagation of cracks in brittle carbides (WC and Cr 3 C 2 ) present on the surface of coated material is connected to material removal.…”

“…The particles cannot cut the bonding phase due to the vertical impact; the bonding phase wears out due to continuous erodent impaction; cracks in the binder occur along the impingement periphery and in the hard and binder boundary phases; the loss of the bond strength phase leads to successive spallation of loose carbide particles; and the loss of the bonding phase leads to subsequent spallation of free-standing carbide particles. 34 The formation and propagation of cracks in brittle carbides (WC and Cr 3 C 2 ) present on the surface of coated material is connected to material removal. Sharp edges of erodent particles skimmed across the material surface created certain areas of shallow cutting on the surface of the WC + Cr 3 C 2 composite coating.…”

“…It was shown that WC-based coating exhibited better abrasive wear resistance compared to Cr 3 C 2 -based coating, possibly due to the higher hardness of WC particles and better matrix properties of the CoCr binder material. [29][30][31][32][33][34][35][36] Zhang et al 37 compared two distinct coatings on H13 steel, WC10Co4Cr and Cr 3 C 2 -25NiCr, and observed that decarburization during spraying results in the formation of the W 2 C phase in the tungsten carbide coating and the Cr 7 C 3 , Cr 23 C 6 phases in the chromium carbide coating. Bhosalea et al 38 reported the erosive wear mechanism of thermal-sprayed WC-Cr 3 C 2 -Ni coatings on SS316L and found that surface characteristics in both coated samples exhibited evidence of erodent plowing and cutting action of varying intensities, leading to heterogeneous erosion mechanisms.…”

“…Some researchers compared the abrasion wear resistance of WC‐ and Cr 3 C 2 ‐based coatings on steel substrates. It was shown that WC‐based coating exhibited better abrasive wear resistance compared to Cr 3 C 2 ‐based coating, possibly due to the higher hardness of WC particles and better matrix properties of the CoCr binder material 29–36 . Zhang et al 37 .…”

Microstructure and Tribo-Behavior of WC–Cr3C2–Ni Coatings by Laser Cladding and HVAF Sprayed: A Comparative Assessment

“…From the above research, it was known that WC–Cr3C2–Ni is one of the most important commercially powder to prepare high-wear resistant coatings for steel substrate [ 14 , 15 , 16 ]. Herein Cr 3 C 2 was strengthening phase and metal Ni worked as binding phase.…”