Laser-induced precipitation of (W1- xCrx)2C: mixed carbide phase for improved wear resistance of thermally sprayed hardmetal coatings

The mixed hemicarbide phase (W1- xCrx)2C is introduced in this work as an appropriate substitute for the pure tungsten carbide WC in thermally sprayed hardmetals acting as wear resistant coatings for various industrial applications. Dedicated laser post-treatments turn out to be most suitable means to precipitate the desired mixed carbide phase from the binder matrix of Cr3C2-37WC-NiCoCrFe coatings, which is left after spraying with considerable degree of supersaturation with excess tungsten, chromium and carbon from spraying-induced carbide dissolution. Major improvements of the coatings resistance against abrasive wear under high-stress conditions at room temperature and at 800 °C as well as under low-stress ASTM G65 conditions can be attained by the laser post-treatments, so that the performance of industrial benchmark coatings of WC-10Co4Cr and Cr3C2-25NiCr can be nearly met or surpassed respectively.