Materials technology

Heat treatment

Today materials with well-defined properties are used for most applications. For material selection the costs for raw material and production plays an important role, just as the chemical and physical specific values. Fraunhofer IWKS developed and optimized heat treatment processes to improve materials properties and to lower the production costs.

Our activities comprise the production of ceramics and metals with powder metallurgy processes like sintering. The properties of such sintered materials are a function of the process parameters like heating and cooling rate, sintering temperature, atmosphere and annealing treatment. With our thermo-optical measuring device we can measure in-situ the shape change and shrinkage behavior during sintering even from complex formed green bodies in two spatial directions simultaneously.

Another field of application is the improvement of magnetic properties and simultaneous reduction of heavy rare earth (HRE) content with a diffusion treatment, the so-called grain boundary diffusion process. By this heat treatment process the coercivity of a magnet can be improved thus minimal amount of HRE elements are diffusing at the grain boundaries from the surface into the magnet and enrich at the outer zone of the Nd2Fe14B grains. The result is a core-shell structure with higher magneto crystalline anisotropy where the HRE elements are concentrated at the outer region. As a consequence of the reduction of HRE amount the costs are reduced.