Wear resistant internal combustion engine component - has thermally sprayed cemented carbide layer containing cubic titanium carbide-based hard phases.

Abstract
A wear resistant internal combustion engine component, especially a piston ring, has, on its wear surfaces, a 50-400 (preferably 100-300) microns thick thermally sprayed layer comprising cubic hard material phases, which contain titanium, carbon and optionally another metal, and a metallic binder phase. Preferably, the layer is formed by thermal spraying of a coating powder having a cemented carbide-like microstructure and consisting of two cubic hard material phases, forming a clad core particle structure with the hard material phase consisting mainly of Ti and C in the core and of Ti, a second metal and C in the cladding, embedded in a binder phase of Ni, Co and/or Fe. Also claimed is a process for producing the above component, in which the layer is applied by plasma spraying in air or high velocity flame spraying (HVOF), metal ions preferably being transferred from the hard phases to the binder phase by oxidation during spraying. USE - The layer system is used especially on a pisto n ring or possibly on other integrated circuit engine surfaces, e.g., cylinder walls. ADVANTAGE - The component is provided with an inexpensively produced, burn track resistant, wear protection layer which can be adapted to engine requirements by alloy composition modification and which exhibits optimal retention of wear resistance in tribological systems. When used on piston rings, the layer exhibits at least 10 times lower weight loss in a 400 cycle thermal shock test and provides 50% reduction in piston ring wear and 20% reduction in cylinder liner wall wear in an engine test, compared with a plasma sprayed Mo-NiCrBSi coating.