Preparation and Friction and Wear Properties of WC Gradient Wear-Resistant Coating by Laser Cladding

Titanium alloys exhibit promising application prospects in ultra-deep well drilling.To enhance the surface wear resistance of titanium alloy drill pipes， WC gradient wear-resistant coatings were fabricated using laser cladding technology.The microstructure， phase composition，elemental distribution， mechanical properties， and tribological performance of the gradient coatings were systematically investigated through OM， SEM， EMPA， XRD， hardness tester， friction and wear tester and white light interferometry.Results demonstrated that the gradient coatings primarily consisted of α-Ti，WC，TiC，TixW(1－x) solid solutions，and minor Y2O3.There were interdiffusion layers with a thickness of several tens of micrometers between the gradient coating layers and the bottom layer and substrate， and the metallurgical bonding was formed between the layers， which improved the bonding property of the coating.Meanwhile， the top layer of the gradient coating exhibited 1.45 times higher wear resistance compared to TC4 substrate.Both TC4 substrate and gradient coatings displayed wear mechanisms dominated by adhesive wear and abrasive wear， while the wear resistance of gradient coatings was higher than that of the substrate.