| 摘要 |
<p>A plasma spray apparatus capable of directing plasticized powders against a substrate for deposition of a protective coating thereon comprises a nozzles extension assembly (12) having a plasma cooling zone (28), a plasma acceleration zone (30), a powder injection zone (32) and a plasma/powder discharge zone (36) affixed to the downstream end of a conventional plasma generator (10). Various structural details of the apparatus described enable the attainment of high particle velocities without melting the particles. The technical concepts employed are directed to normalizing the temperature of the plasma stream at a reduced value prior to the injection of coating particles. A general reduction in temperature and substantially elimination of a thermal spike at the core of the stream are achieved. Coating particles are injected into the plasma stream only after the plasma is first cooled and then accelerated. Details of dimensions and operating conditions are given. <IMAGE></p> |
