A comparative assessment on the characteristics of HVOF sprayed cermet coatings

High Velocity Oxygen Fuel (HVOF) process enables superior properties and is foreseen as a suitable candidate for deposition of hard chromium alternative coatings over the other surface hardening techniques like cladding/deposition through electrolysis/CVD methods, owing to the widespread adaptability and preference in aerospace industry, in particular landing gear mechanism and associated modules that operating in severe environments encountering abrasion, erosion, sliding and fretting wear. Cermet coatings are very often utilised to intensify the wear and corrosion resistance of a wide range of engineering components. The objective of this work is to develop thermally sprayable oxides, nitrides and carbides of WC and Cr3C2 cermet coatings on AISI 4340 steel by HVOF technique. The modified surface is characterised by SEM/EDAX study, followed by the evaluation of Porosity and Microhardness of the modified different speeds and loads. The study unveiled that of all the stated coatings, the blend of WC-Co-VC matrix yields superior hardness, Coefficient of friction and lower order of porosity. The observation forefronts the enhancement of wear properties in terms of surpassing wear resistance and declining trend in volume loss compared to other compositions.