Tribological Behavior of WC-Co/NiCrAlY Coatings on Ti-6Al-4V

Ti6Al4V alloys are widely used in chemical plants, automobile, aerospace industries and medical applications (bone, dental) because of its high specific strength. But, it has poor wear resistance. In the present investigation, duplex coatings were employed to enhance the mechanical and tribological properties. WC-Co Ceramic coatings were deposited on Ti6Al4V substrate with different thicknesses (250μm, 350μm and 450μm) by the detonation spray (DS) while the thickness of the NiCrAlY bond coat (200μm) deposited by High Velocity Oxy Fuel (HVOF), stayed the same. Mechanical properties (hardness and wear resistance) were found for both substrate and duplex coatings. Wear test was performed for different sliding distances (1000m,2000m,3000m and 4000m) at a constant load of 50N by using a pin-ondisc apparatus, and the disc speed was recorded as 600rpm. XRD characterization was performed for substrates and coated samples. SEM analysis showed the wear behavior of coated and uncoated samples. Finally, it was concluded that 450μm ceramic top coat samples resulted maximum hardness and highest wear resistance.