Densification of porous tungsten by low temperature sintering

Abstract

Tungsten (W) has one of the highest melting points (3410±20°C) among the elements in the periodic table and therefore has gained considerable attention for high temperature applications such as porous tungsten as a high current density cathode for flash lamps or electronic valves. Its brittle behaviour and high density have also been important factors in the processing methods employed. Through the years it has been processed mostly using PM techniques in order to obtain different forms. To obtain densification, it is necessary to apply high temperatures during sintering. This paper considers a novel approach to the pressing and sintering of tungsten powders and how their densification can be improved. One potential aid is to add very small amount of Al as a binder. The densification characteristics are presented using SEM analysis to develop the underlying mechanisms.