Development of Advanced Ceramics by Powder Composite Process

Abstract

A powder composite process was applied to develop several kinds of advanced ceramics. TiO2 nanoparticles and Si3N4 particles were mixed using a powder composite process to disperse TiN nanoparticles in Si3N4 ceramics, which are expected to be used as novel materials for next-generation hybrid ceramic bearings. TEM observations showed that the TiO2 nanoparticles were directly bonded to submicron Si3N4 particles. Si3N4 ceramics with uniformly-dispersed TiN nanoparticles were fabricated using the composite particles. The amount of damage caused by the Si3N4 ceramics with TiN nanoparticles to the mating metals in a ball-on-disk test was comparable to the damage caused by Si3N4 ceramics without TiN particles. Nanocomposite particles of Al2O3-doped ZnO prepared by a powder composite process were also used for fabricating ZnO ceramics. TEM observations revealed the uniform presence of Al2O3 nanoparticles on ZnO particles. A sintering body fabricated using the composite powder prepared by this powder composite process had more uniform and finer microstructures than that fabricated using a powder mixture prepared by conventional wet mixing. The ZnO ceramics prepared by the powder composite process exhibited higher electrical conductivity than those prepared by the conventional wet ball milling process. CNT-dispersed Al2O3 ceramics were fabricated using a powder mixture of CNT and fine Al2O3 powder prepared by the powder composite process. It was shown that CNTs were uniformly dispersed in the developed CNT-dispersed Al2O3 ceramics, and that they had high electrical conductivity and strength.