Process and product developments for niobium, tantalum, molybdenum and tungsten

The refractory metals niobium, tantalum, molybdenum and tungsten as well as their alloys, intermetallic and other compounds plus the derived composites exhibit outstanding properties and are therefore widely spread in the industrialized world. Some of their areas of application, where refractory metals could not be easily replaced by other substances, are for example the use as material for implants, the production of capacitors for the electronics industry as well as the utilization in superconductive magnetic coils of particle accelerators, thermonuclear fusion reactors (ITER) and for the magnetic resonance tomography (medical diagnosis). A further application in the form of hard metals or cermets is the chipping of wood and metals as well as rocks by turning, milling and drilling besides numerous other uses. The research in the field of materials science followed during the last years the objective to develop new refractory metal containing substances and to improve the properties of existing ones. The design of nanocrystalline materials is for example the ambition of research programs in the whole world since two decades. However, these new matters require special processes and technologies for their production and processing to achieve the desired results. This paper gives for this reason an overview about the process and product developments in this area as well as about the achievable properties and the resulting fields of application. (orig.)