Low frequency plasma spray method in which a stable plasma is created by operating a spray gun at less than 1 MHz in a mixture of argon and helium gas

摘要

A low frequency RF plasma spray deposition method is provided, which is especially effective in reducing losses and improving particle heating. In one aspect of the invention, an RF plasma gun is operated in the frequency range below 1 MHz and an argon-helium mixture to which a third component, such as hydrogen, can also be admixed, is substituted for the standard argon-hydrogen mixture used at frequencies above 2 MHz. In another aspect of the invention, a RF plasma gun is operated in the frequency range of 400-500 kHz and specific start up and operating procedures and conditions are set forth for successful deposition of titanium and refractory metal alloys.