The preparation and properties of tantalum and some of its alloys

Abstract

The study of tantalum, its compounds and alloys, first began in Melbourne in i942. It was undertaken as part of a programme to investigate the effect of adding hard, high melting point, metallic carbides, eg. tantalum carbide, to the tungsten carbide compacts which were being studied for tool tipping purposes. The early stages involved the development of a method for separating tantalum oxide and columbium (niobium) oxide from an ore which occurred abundantly in the Western States of Australia. This work, together with a review of the literature on the subject and the results of an investigation into a method of preparing pure tantalum and columbium carbides, has been described earlier.

Because of the war situation it was considered more important to develop to the pilot scale, a plant for producing pure tantalum oxide and consequently the carbine work was discontinued. After the pilot plant had been established, work on tantalum ceased for two years owing to pressure of other problems in connection with the refractory metals project at the University. Subsequently, it was possible to return to a study of tantalum and the first step was to investigate the factors involved in the preparation of the metal. The electrolytic process was studied in some detail and this was followed by experiments on the consolidation of the tantalum powder produced. Apparatus for the high temperature, vacuum heat treatment of the pressed compacts was developed and methods of working and fabricating tantalum were studied. Some of the properties of consolidated tantalum were determined and the effect of deformation on these properties, and on the annealing temperature, was investigated. Finally the effect of alloying other high melting point metals with the tantalum was studied.

The results of most of the work have been assembled in the form of papers, some of which have been published and others are ready for publication. These will be included as appendices to the thesis and will be, referred to frequently. The thesis will serve to link the various papers together to form a consolidated picture of the investigation to date. (From introduction)