SiCのコロイドプロセッシングと液相焼結

概要

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Colloidal dispersion and pressure-casting to prepare SiC green pieces of two types and pressureless sintering of SiC were sequentially conducted to obtain homogeneous, dense SiC bodies. Polyethyleneimine (PEI) was selected as a dispersant, and Al_2O_3/Y_2O_3 additives served as a sintering aid for the ceramic systems. The dispersion behavior of the SiC in solutions with PEI dispersant was characterized by their surface potential and isoelectric point (IEP), and interpreted according to the chemistry and adsorption of the PEI dispersant. The resulting crystalline phases and grain morphologies of sintered SiC were investigated by quantitative X-ray diffractometry (QXRD), scanning and transmission electron microscopies (SEM & TEM) and high resolution transmission electron microscopy (HRTEM). α-SiC was sintered at ambient pressure to a higher density than β-SiC with Al_2O_3 and Y_2O_3. The densification and resulting microstructure depended greatly on the polytypes of the starting SiC powders, types of packing powder to buy samples, and types and amount of sintering additives. The effects of seeding with 6H-SiC powder on phase evolution, the transformation temperature and densification of the β-SiC matrix are discussed.
社団法人日本セラミックス協会の論文
1995-05-01