METHOD AND APPARATUS FOR APPLYING A COATING

A method according to the invention for applying coatings resides in the fact that a powder with a particle size from 1 to 50 .mu.m made of a material selected from the group consisting of medals, alloys, their mechanical mixtures or insulating materials is introduced in an amount for ensuring a density of flow rate from 0.05 to 17 g/s?cm2 into a gas flow for forming a gas and powder mixture which is directed towards the surface of a product, a supersonic velocity being imparted to the gas flow , and a supersonic jet of a predetermined profile being formed which ensure a velocity of powder in the gas and powder mixture from 300 to 1200 m/s. An apparatus for carrying out the method has a powder particle flow controller mounted in a spaced relation to a cylindrical surface of a drum to ensure the desired flow rate of the powder, an intermediate nozzle adjacent to a mixing chamber communicating through its inlet pipe with a means for supplying a compressed gas,a deflector mounted on a hopper bottom and engaging the cylindrical periphery of the drum in which depressions are made along a helical line, the drum extending horizontally in such a manner that one portion of its cylindrical periphery forms the bottom of the hopper and the other portion forms a wall of the mixing chamber, a nozzle for accelerating the powder particles being in the form of a supersonic nozzle and having a profiled passage.