Liquid phase sintered silicon carbide composites

It has been showed that Silicon carbide can already be sintered to more than 98percent of the theoretical density at already 1900 deg. cent by using liquid phase sintering additives. By variation of SIC-powder, the type and concentration of additive it is possible to achieve a wide range of structures and properties corresponding to the demands of application. Applying the liquid phase sintering technique a broad variety of SiC based composites are possible to obtain. This work shows some examples, e.g. SiC-TiC/SiC-ZrC particulate composites and SiC-Platelet/SiC-composites. SiC-TiC particulate composites with TIC concentrations of 0-100 wt% were found to be pressureless sinterable to full density. A thin layered composite with gradually changing TiC-content was also obtained without delaminations. An isotropic and homogeneous arrangement of the platelets has been obtained in SiC-Platelet/SiC-Composites by using conventional PM processing (mixing and die pressing). Injection and hot mou lding of thermoplastic mixtures as well as extrusion experiments have shown effects on platelet alignment and densification. Composites containing 10 to 15 % platelets were densified to more than 95% th.D. by using pressureless sintering technique. The results essentially demonstrate the possibility of producing reinforced SiC-composites which are normally hard to obtain.