Effect of Heat Treatment on Wear Performance of Nanostructured WC-Ni/Cr HVOF Sprayed Coatings

Abstract

The extraction and processing of bitumen from oil sands exposes machinery parts to constant abrasive wear which can cause severe surface degradation and component failure, resulting in production shut-downs. To reduce the effect of wear on performance of production machinery, wear resistant coatings must be used to extend component life. Recently, thick microstructured cermet coatings based on WC dispersions have been used to protect surfaces. In this study a nanostructured 83WC-17Ni/Cr coating was deposited on to C-Mn steel surfaces using High Velocity Oxy-Fuel (HVOF) spraying. The effect of heat treatment in air and nitrogen atmosphere on changes in the microstructure, hardness and wear resistance was investigated. The results showed that both the hardness and wear resistance increased with increasing heat treatment temperature in both air and nitrogen atmosphere. However, the use of heat treatments in air led to the formation of brittle metal oxides which resulted in micro-cracking within the coatings. This caused the coatings to fail by brittle fracture during wear testing. In comparison heat treatment in nitrogen produced better wear resistance because metal oxide formation was avoided.

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

“…Therefore, seeking a suitable surface coating to improve wear resistance of SK5 steel has become an urgent need to be served. Tungsten carbide (WC) is an important class of wear-resistance material and can be well adjusted by metal melts such as Co, Fe, and Ni, which are widely used to prepare wear-resistance coatings on the surface of mechanical parts [ 1 , 2 , 3 , 4 ].…”

Ann Supported Study on the Performance and Slurry Erosion Resistance of Thermal Sprayed Wc20cr3c27ni Coatings

“…The hard phases commonly utilised in coatings to improve erosion resistance are WC or Cr 3 C 2 . WC-based coatings, such as WC-Co, WC-Ni, and WCCoCr, are typically employed in erosion and abrasive phenomena [7][8][9][10]. When chemical stability is necessary, Cr 3 C 2 -based coatings are frequently employed.…”

“…For example, Cr 3 C 2 -NiCr coatings are used in engineering applications due to their strong tribological characteristics under severe working environments [11,12]. According to recent ndings, the coating processed by spraying WC20Cr 3 C 2 7Ni powder outperformed the coating formed by spraying powder containing only tungsten carbide or chromium carbide [7][8][9][10][11][12][13][14][15][16]. Thermal spray is a family of deposition techniques used in coating fabrication that deposit nely fragmented non-metallic or metallic materials in a molten or semimolten state [17].…”

Wear and corrosion behaviour of the cryogenically treated tungsten carbide coatings

“…Gallego et al reported that heat-treatment of WC-based coatings at a lower temperature 350°C, provides better wear resistance than at a higher heat treatment temperature due to the microstructural defects related to the oxidation during heat treatment [16]. So, heat treatment should be performed in an inert environment or vacuum to reduce the chances of oxidation that leads to deterioration of the wear resistance of the coatings [2,5,13,16].…”