Electrical Discharge Machineable Ceramic Composites (Vonkerodeerbare keramische composieten)

The application of extremely hard ceramic composites can potentially increase the wear resistance of tools and parts considerably. However, their high hardness makes them also nearly impossible to machine using classical diamond or cBN tools and severely limits the geometrical freedom of the machining process due to the constraints posed by these machining methods. Electrical Discharge Machining (EDM) allows for the production of intricate parts regardless of hardness and is therefore ideally suited for machining ceramic composites, requiring only sufficient electrical conductivity. In this dissertation, three novel conductive ceramic composite classes have been developed (WC-ZrO2,NbxZr1-xB2-SiC, TixZr1-xB2-SiC). Pulsed Electric Current Sintering (PECS) was used as a consolidation technique in order to retain fine microstructures which lead to superior hardness and strength. The influence of microstructure, composition and processing route on the EDM behavior was investigated on these three novel classes and on two additional ceramic systems (B4C-TiB2, Si3N4-Carbon Nanotubes).nrpages: 176status: publishe