Tape casting of functionally graded AIN-SiC-MoSi2 composites

In the view to develop a novel class of electroconductive ceramics where the conductive phase is molybdenum disilicide, composites with AlN-SiC-MoSi 2 at 55/15/30 and 60/20/20 vol% concentration respectively were produced by tape casting and sintering. Two compositions were designed in order to tailor the electrical resistivity of functionally graded components, which are constituted by two or more portions of the studied composites. In order to optimise the tape casting process, the non-aqueous ceramic suspensions were investigated controlling binder and plasticizer content and the binder to plasticizer ratio. Compositions of the slurries were related to the green and final density and to the microstructural features of mono and multilayers samples. Controlled debonding and sintering tests were carried out under nitrogen atmosphere at temperatures of 1850°C, with appropriate heating gradients, protecting the samples in a powder bed. Density and microstructure of the sintered samples were examined and correlated to the processing conditions.