Influence of heat treatment on the abrasive wear resistance of a Cr3C2-NiCr coating deposited by an ethene-fuelled HVOF spray process

This work studies the influence of heat treatments on the microstructure, mechanical properties and abrasive wear behaviour of a Cr3C2-NiCr coating deposited by high-velocity oxygen-fuel spraying using an agglomerated and sintered feedstock powder. The wear resistance of as-sprayed and heat treated (8 h at 800 °C) coatings was evaluated in low- and high-stress abrasion regimes, the latter in a temperature range up to 800 °C. Precipitation of secondary carbides from the supersaturated as-sprayed binder matrix is at the core of the observed changes in the coatings wear resistance upon heat treating. This aging process renders the binder matrix softer and more ductile, as was probed by means of nanoindentation, and thereby improves its resistance against micro-cracking which is identied as an important wear mechanism in high-stress abrasion conditions.