Wear and impact resistance of HVOF sprayedceramic matrix composites coating

Ceramic coating has the mechanical properties of high hardness and it is well known for application on wear resistance, but on the other hand the resistance to impact load is low. Therefore its use is limited to applications that have no impact loading. The aim of this research was to obtain ceramic-metallic composite coating which has improved impact resistance compared to conventional ceramic coating. The high impact resistance of ceramic-metallic composite coating is obtained from dispersed metallic alloy phase in ceramic matrix. Ceramic Matrix Composites (CMC) powder with chrome carbide (Cr₃C₂) base and ceramic-metal NiAl-Al₂O₃ with various particle sizes as reinforced particle was deposited on mild steel substrate with High Velocity Oxygen Fuel (HVOF) thermal spray coating. Repeated impact test showed that reinforced metallic phase size influenced impact resistance of CMC coating. The ability of CMC coating to absorb impact energy has improved eight times and ten times compared with original Cr₃C₂ and hard chrome plating respectively. On the other hand the high temperature corrosion resistance of CMC coating showed up to 31 cycles of heating at 800°C and water quenching cooling.