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A SiC powder of median size 0.8 mm was mixed with polyacrylic acid PAA, dispersant in a 0.3 moll-RNO 3 3 solution RࢼYb, Y, Gd, Sm, Nd and La at pH 5 to adsorb uniformly the sintering additive R 3ࢪ ion on the SiC surface. The aqueous 30 volಚ SiC suspension with 0.52 massಚ PAA and 1.50 massಚ R 2 O 3 as RNO 3 3 , relative to SiC, was consolidated by filtration through a gypsum mold to form green compacts of 50-52ಚ of theoretical density. The consolidated green compacts were densified with grain growth to 76-99ಚ relative density by hot-pressing under a pressure of 39 MPa at 1950c C for 2 h in an Ar flow. The addition of R 2 O 3 of smaller R 3ࢪion was effective to enhance the sinterability of SiC and also to achieve smaller grain size of SiC. This result was discussed based on the additional experiment result on the chemical interaction between SiC compact and the SiO 2 -R 2 O 3 liquid. The average flexural strength and Weibull modulus of dense SiC were 612 MPa and 5.1, 719 MPa and 6.7, and 731 MPa and 9.8 for Gd 2 O 3 , Y 2 O 3 and Yb 2 O 3 addition, respectively.

This investigation describes the experiment directed toward the production of monodispersed toner particles by suspension polymerization. That is, relatively monodispersed poly(styrene-co-divinylbenzene) microspheres containing electrifying additives were successfully prepared by suspension polymerization employing the Shirasu Porous Glass (SPG) membrane emulsification technique. The diameter distribution of the dispersed droplets prepared with an SPG membrane module was fairly narrow, compared with that prepared with a conventional mechanical homogenizer. The effect of Sumiplast Blue S as coloring matter and E-81 as charge control agent on the triboelectric discharging properties of prepared polymeric microspheres was studied. The addition of electrifying additives strongly affected the triboelectric discharging property. It was consequently clarified that a small amount of electrifying additives added raised the electrostatic capacity of polymeric microspheres. However, a further addition reduced the triboelectric discharge of polymeric microspheres.

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