A CELL AND METHOD FOR FORMING A COMPOSITE HARD MATERIAL AND COMPOSITE HARD MATERIALS FORMED THEREBY

摘要

A cell for forming a composite hard material and hard materials and methods of forming composite hard materials are disclosed. A cell (10) in which the article is formed includes a talc outer sleeve (12), a glass sleeve (14) and a reflecting foil (22). A heater (18) is arranged inwardly of the foil (22) and a barrier layer (16) is arranged inwardly of the glass sleeve (14). A central column (20) is defined for receiving the charge of material (50) from which the hard composite material is to be formed. The charge material is located in a mould (76, 100) which can define the final shape of the article thereby avoiding the need for additional machining, and the mould and charge material are subject to high temperature and pressure to form the composite material whilst maintaining the charge subject to hydrostatic pressure during the application of pressure and high temperature and maintaining a low temperature gradient across the charge during formation of the composite hard material to reduce uneven pressurisation of the composite hard material. The article may also be formed by forming first and second mixtures (120, 130) of composite hard material so as to form an outer surface on the article which has a higher hard particle content than an interior core portion of the article.