Abrasion and Erosion Behaviour of Fine Carbide-laden Metallic Coatings Deposited by Hybrid Powder-Suspension Plasma Spraying

Coatings comprised of a ductile metallic matrix with a hard carbide reinforcement are promising candidates for diverse wear resistance applications. The tribological properties of such coatings have also been reported to improve with reduction in carbide particle size, besides being influenced by the carbide content. Plasma spraying of hybrid powder-suspension feedstock provides a unique approach to conveniently create such composite coatings by simultaneously feeding a conventional “coarse” spray-grade powder and a suspension of “fine” sub-micron sized carbide particles. The vastly different length scales of the two powder constituents yields coatings with characteristics very distinct from those of conventional plasma sprayed coatings. This paper describes the processing of such hybrid sprayed composite coatings, using two different carbide-containing coatings for illustration. Coatings with varying chromium carbide and titanium carbide contents in a Triballoy 400^® matrix have been comprehensively characterized. The abrasion and erosion behaviour of the coatings will also be discussed.