High-Velocity Oxy-Fuel (HVOF) coating

High-velocity oxy-fuel (HVOF) is a thermal-spray process that burns a fuel gas or liquid fuel with oxygen at high pressure to accelerate molten or semi-molten powder particles, usually tungsten carbide-cobalt or a nickel-chromium alloy, onto a component at supersonic speed. The result is a dense, low-porosity, high-bond-strength coating that resists wear and corrosion. In marine work it is applied to propeller shafts, stern-tube journals, pump and valve parts, and hydraulic rams as an alternative to hard chrome plating. The high particle velocity and lower flame temperature than plasma spraying limit carbide decomposition, giving the hardness and adhesion that shaft seal areas require.