Microstructure Investigation of WC-Based Coatings Prepared by HVOF onto AZ31 Substrate

Abstract

In this paper, three commercial cermet powders, WC-Co-Cr, WC-Co and WC-Cr3C2-Ni, were sprayed by the High Velocity Oxy Fuel (HVOF) method onto magnesium alloy AZ31 substrate. The coatings were investigated in terms of their microstructure, phase analysis and residual stress. The manufactured coatings were analyzed extensively using optical microscopy (OM), X-ray diffraction (XRD), scanning (SEM) and transmission electron microscopy (TEM). Based on microstructure studies, it was noted that the coatings show satisfactory homogeneity. XRD analysis shows that in WC-Co, WC-Co-Cr and WC-Cr3C2-Ni coatings, main peaks are related to WC. Weaker peaks such as W2C, Co0.9W0.1, Co and W for WC-Co and W2C, Cr3C2 and Cr7C3 for WC-Cr3C2-Ni also occur. In all cermet coatings, linear stress showed compressive nature. In WC-Co and WC-Cr3C2-Ni, residual stress had a similar value, while in WC-Co-Cr, linear stress was lower. It was also proved that spraying onto magnesium substrate causes shear stress in the WC phase, most likely due to the low elastic modulus of magnesium alloy substrate.

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

“…WC–Co‐based coatings protected the steel substrates from wet and dry abrasion conditions and also observed that finer WC particles were associated with increased wear resistance 6–11 . Jonda et al 12 . and Mendez‐Medrano et al 13 .…”

“…WC-Co-based coatings protected the steel substrates from wet and dry abrasion conditions and also observed that finer WC particles were associated with increased wear resistance. [6][7][8][9][10][11] Jonda et al 12 and Mendez-Medrano et al 13 evaluated the microstructure and phase characterization of tungsten carbide and chromium carbide coatings. They noticed that the X-ray diffractometry (XRD) pattern of the coatings indicated the WC and Cr 3 C 2 decarburization phases and disintegration of WC particles occurs, resulting in substantial amounts of W 2 C, W, and Co 3 W 3 C. Schwetzke et al 14 and Matikainen et al 15 investigated the microstructure of WC-based coatings on mild steel substrates.…”

The Effect of HVOF Spray Distance on Solid Particle Erosion Resistance of WC-based Cermets Bonded by Co, Co-Cr and Ni Deposited on Mg-alloy Substrate

“…In our previous work, corrosion resistance, abrasive wear and cavitation erosion were tested [26,27]. Moreover, the detailed microstructure investigations were carried out [28]. Testing the resistance of coatings to erosive wear caused by solid particles is the next stage of the research plan.…”

Investigations on the Microstructure and Corrosion Performance of Different WC-Based Cermet Coatings Deposited by High Velocity Oxy Fuel Process onto Magnesium Alloy Substrate

“…Also thermal spraying methods could be used in order to manufacture coatings on magnesium alloys, as follow: cold spray [29], arc spray [30,31], detonationgun [32], flame spray [33] and plasma spray [34,35]. As it was described in previous papers [36,37], high velocity oxy fuel (HVOF) method is the most promising, especially for cermet coatings deposition. Although coatings sprayed on AZ31 alloy substrates are already well described [38], there is a gap in the literature related to the application of coatings on AZ91 alloy substrates.…”