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| Thermal spray is a surface treatment process that the subtle and dispersed metal or non-metallic coating materiallike wire or powder in a melt or semi-molten state, deposits on the substrate surface to form a sort of deposited layer. Thermal spray material is heated to a plastic or molten state and then accelerated. While these particles hitting the substrate surface, they are deformated due to pressure, form layered sheet, and adhere to the substrate surface. They continuously accumulate and eventually form a layered coating. By changing coating materials, different functions can be realized such as erosion resistance, abrasion resistance, heat insulation, ceramic insulation and so on. |
| Today, as a high-tech technique, thermal spray has been widely used in aerospace, automotive, energy, metallurgy, paper making, machinery maintenance, municipal construction and other areas. |
| In engineering and mechanical surface treatment areas, thermal spray technology is the most effective, economic and direct process to enhance the surface functions and parameters. Through the use of thermal spray technique, it can improve the life of equipment or spare parts, improve the surface performance, as well as reduce production and maintenance costs. |
| Thermal spray features include: abrasion resistance, heat-resistant barrier; anti-erosion; restore size; gap control; change in electrical conductivity, etc. |
| HVOF Coating Process (High Velocity Oxygen Fuel) |
| HVOF Coating Process (High Velocity Oxygen Fuel) |
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| With the principle of rocket engines, HVOF thermal spray, uses aviation kerosene as fuel, oxygen as the combustion supporting gas, forms the mixed gas by high-performance aerosol. After combustion, the mixed gas becomes a hot high pressure flame and the Laval nozzle accelates its velocity to supersonic flow.The speed of coating material particles plays an important role to the coating performance. When the particles hit the substrate surface, its high-speed |
| produces a huge impulse, and the particle deformation ability is strong, which is conducive to the formation of a high binding and high density coating. |
| The binding strength test of common WC-12Co coating shows that the binding strength exceed to 70Mpa. |
| Conventional spray material: Al2O3；Al2O3-3%TiO2；Al2O3-13TiO2；Al2O3-40TiO2 ；Co2O3；ZrO2-8%Y2O3；TiO2 | |
| Plasma Coating Process |
| In all thermal spray techniques, plasma spray is the most flexible one as it can reach a sufficient temperature to melt or heat any material, so the coating material types are almost unlimited. |
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| Plasma spray gun is composed of a small chamber with a cathode (electrode) and an anode (nozzle). Broken down by high-intensity arc, the gas through the chamber forms plasma substance, and releases large amount of heat, which can reach the temperature of 6000 ℃ ~ 16000 ℃. When the coating material is high-speedly injected into the gas flame, it is melted and impacts on the substrate surface. |
| Conventional spray materials: Al2O3；Al2O3-3%TiO2；Al2O3-13TiO2；Al2O3-40TiO2 ；Co2O3；ZrO2-8%Y2O3；TiO2 | | |
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