Rheological properties of silicon carbide hot-moulding slips

At all casting processes, the flow behaviour of moulding formulations plays an important role. In thermoplastic slips for hot moulding maximum solid contents at optimal rheological properties are necessary. For the stability of the green parts against deformation during dewaxing, a significant yield stress is favourable. At higher shear rates the flow character of the hot moulding slip has to be near-newtonic. Strong effects of dilatancy have to be avoided. The topic of the paper is the investigation of the rheological properties of hot moulding slips for manufacturing of sintered silicon carbide. The influence of the flow behaviour of hot moulding slips on the binder composition, on the specific surface area of the SiC-powder, on the solid content and on temperature are discussed. For that purpose both model systems and thermoplastic slips for manufacturing have to be examined.