... HVOF APS .Small, medium grain gize tungsten carbide .The highest working temperature 500 °C .Alternative hard chromium .Cobalt chromium lattice resistance ... hydropower turbines, pump parts, paper roller, gate valves, ball valves, hydraulic cylinder, compressor shaft, etc. .Near proteetion in corrosive solutions ... using HVOF sprayed ,coating to achieve the effect: Tungsten carbide powder WC-10%Co-4%Cr