Microstructure and wear resistance of Fe based TiB₂ composite coating

Fe based TiB₂ composite coating was in situ synthesised by plasma transferred arc cladding. The microstructure and microhardness of the composite coating were investigated by optical microscopy, SEM and microhardness tester. Sliding wear behaviour of the composite coating was investigated on a block on ring wear tester rubbing against GCr15 steel ring. Wear resistance of TiB₂/Fe composite coating was 16-25 times than that of the uncoated iron matrix. The good interfacial bonding between TiB₂ particles and iron matrix led to no transition from mild wear to severe wear over the applied load range. The sliding wear resistance of the composite coating decreased with increasing sliding speed and applied load. The wear mechanism of the composite coating was a comprehensive action of microcutting wear, surface flaking, adhesive wear, slight abrasive wear and fatigue wear. High applied loads resulted in particle detachment and accelerated the abrasive wear and the fatigue wear.