Dry sliding wear behaviour of WC-Co coating on Ti6Al4V using Thermal Spray coating technique

Abstract

The titanium alloys are extensively using in defence, aerospace, automobile, chemical plants and biomedical applications due to their very high strength and lightweight properties. The most commonly used titanium alloy is the two phase Ti6Al4V. But, it has poor wear and corrosion resistance when exposed to different environment conditions. In this work, surface coatings were applied on Ti6Al4V substrate using high velocity oxy fuel (HVOF) to improve wear characteristics. The ceramic coating (WC–Co) were deposited on Ti6Al4V substrate with different thicknesses 300µm, 400µm and 500µm.

In the present investigation, hardness of both coated specimens and substrate were found by conducting Vickers hardness test. The cross sectional and surface morphology of substrate and coated system with varying thickness were made using SEM.

Pin-on-disc tests are performed for evaluating sliding wear behaviour of substrate and coated system where the counter disc was made of chrome steel. Wear test was carried out at different sliding distances of 1000m, 2000m, 3000m and 4000m at a constant load of 50N and the disc speed was recorded as 600rpm. The mass loss of substrate material and coated system was measured for all the test conditions to demonstrate the wear behaviour. SEM analysis showed the wear behaviour of coated and uncoated samples. The mass loss of the above test conditions expressed that the coating system found to be better improvement in wear resistance of substrate. However, the thicker coat samples (500µm) shows maximum hardness and highest wear resistance.