Glow discharge plasma brazing of Fe–Ni alloy in vacuum

Abstract

A novel vacuum brazing technique, termed glow discharge plasma brazing, is investigated. During the brazing process, the heating temperature of base metals is proportional to the square of the operating barometric pressure and the operating voltage, and the temperature distribution of the base metals is easily regulated by means of suitable measures. The ion beam from the glow discharge anode can efficiently sputterclean the surface of the base metals and the filler metal, which improves the wetting and spreading properties of the filler metal. Unlike the traditional vacuum brazing process, a high quality braze of Fe–Ni alloy is achieved at lower vacuum (a pressure of 5– 30 Pa or higher) by using the glow discharge brazing method. The brazing technique has a promising application in industry.