Abstract: An apparatus is disclosed for kinetic spray coating of substrate surfaces by impingement of air or gas entrained powders of small particles in a range up to at least 106 microns accelerated to supersonic velocity in a spray nozzle. Preferably powders of metals, alloys, polymers and mixtures thereof or with semiconductors or ceramics are entrained in unheated air and passed through an injection tube into a larger flow of heated air for mixing and acceleration through a supersonic nozzle for coating of an article by impingement of the yieldable particles. A preferred apparatus includes a high pressure air supply carrying entrained particles exceeding 50 microns through an injection tube into heated air in a mixing chamber for mixing and acceleration in the nozzle. The mixing chamber is supplied with high pressure heated air through a main air passage having an area ratio relative to the injection tube of at least 80/1.

Abstract: A method and apparatus is disclosed for kinetic spray coating of substrate surfaces by impingement of air or gas entrained powders of small particles in a range up to at least 106 microns accelerated to supersonic velocity in a spray nozzle. Preferably powders of metals, alloys, polymers and mixtures thereof or with semiconductors or ceramics are entrained in unheated air and passed through an injection tube into a larger flow of heated air for mixing and acceleration through a supersonic nozzle for coating of an article by impingement of the yieldable particles. A preferred apparatus includes a high pressure air supply carrying entrained particles exceeding 50 microns through an injection tube into heated air in a mixing chamber for mixing and acceleration in the nozzle. The mixing chamber is supplied with high pressure heated air through a main air passage having an area ratio relative to the injection tube of at least 80/1.