窒化ケイ素の泥しょう鋳込成形と焼結体の機械的特性(第3報) : イミド分解窒化ケイ素粉体の泥しょう調製条件

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Slip casting of silicon nitride powder produced by imide decomposition (median particle size=0.55 μm in diameter) was studied to fabricate Si_3N_4 engineering ceramic parts with a complicated shape. The zeta potential of α-Si_3N_4 showing the isoelectric point of pH=7.0 was+32 mV at pH=2 and -47 mV at pH=11. Preparation conditions of well-dispersed slurries were investigated for the mixed powders of 92 wt% α-Si_3N_4, 4 wt% α-Si_3N_4, and 4 wt% Y_2O_3, using an organic polymer deflocculant (polyacrylic ammonium). High-density green bodies (density=1.76-1.82 g/cm^3) were prepared from the slurries containing solids of 67 to 70 wt% by vacuum-filtration with a porous polymer resin mold. High-density Si_3N_4 ceramics were obtained by gas pressure sintering at 1775℃ for 4 h at about 0.9 MPa of N_2 pressure. The samples showed an average flexural strength of 814 MPa and a Weibull modulus of 10.4 at room temperature.
社団法人日本セラミックス協会の論文
1993-04-01