Abstract
Microplasma spraying unit is characterised by small dimensions, low level of noise and emissions, low power consumption (kW*h/kg). The process provides deposition of coatings on small sized parts and components, including those with fine sections, this being unachievable with any other methods. This makes it possible to widen the scales of the application of plasma spraying and to produce different functional coatings. Microplasma jet has diameter 2-4 mm and length 30-50 mm. Velocities of different powder particles in conditions of microplasma spraying were measured. They amount 15- 60 m/s. Coating from iron-, nickel- and copper alloys were produced. Microstructure and properties of this coatings were studied. A real capability was demonstrated of microplasma spraying of narrow strips of 1-3 mm width with 0.2-0.5 mm thickness on the surface of stainless steel sheets of 0.5 mm thickness and of aluminum alloy of 1 mm thickness, as well as on the surface of 2-6 mm diameter cylindrical samples. The spraying spot has the form of an ellipse elongated along the vertical with 1.1-1.5 axes ratio, depending on the spraying conditions.
