DYNAMIC ABRASION RESISTANCE OF COATINGS APPLIED TO ENGINEERING MATERIALS

Combined impact and abrasion tests were conducted on coated and uncoat ed samples of aluminium, mild steel, and tool steels using a purpose b uilt test rig. Tungsten carbide-cobart (WC-Co) coatings of different t hicknesses were deposited using a high velocity oxy-fuel (HVOF) proces s. Experimental work showed that wear rates were greater under impact abrasion conditions compared with pure contact abrasion. As the substr ate hardness increased, the wear rates decreased under the test condit ions. Coated aluminium samples experienced greater wear under impact c onditions than uncoated samples. This was due to deformation of the su bstrate which led to cracking and spalling of the coatings. Impact abr asion produced greater wear on the mild steel than pure abrasion. The tool steels experienced very low wear rates under both test conditions and only slight polishing of the surfaces occurred. Results show that the wear rate on each sample was not affected by the coating thicknes s, but the coating thickness did influence the wear resistance.