SLIP CASTING OF SILICON-NITRIDE AND PROPERTIES OF SINTERED BODY

To develop a shape forming for the obtention of Si3N4 ceramic body slip casting was studied. As the powder characteristics, the zeta potential measurements to pH range 3 - 10 were determined for Si3N4 (by carbothermal reduction of chilean rice husk), bentonite and cupper oxide. The preparation conditions of well-dispersed slurries were determined from viscosity pH curve of whisker- and conrmercial-Si3N4. A mixture of 93 wt% Si3N4, 4 wt% bentonite and 3 wt% cupper oxide yielded a compact green body (15 mm x 50 mm x 2 mm) by slip casting with a porous gips mold. The sintering of these Si3N4 bodies at 1700 degrees C and 1850 degrees C for 2 hours in N2 gas provided a increasing of relative density. XRD- and SEM-analysis were considered to describe this densification behaviour.