CaCN_2を添加したAIN超微粉末の焼結

概要

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The effect of calcium cyanamide (CaCN_2) addition on the sintering of AIN ceramics was investigated. Pressureless sintering was carried out with 0 to 3.0 mass% CaCN_2 addition, and densified sintered specimens (relative density>97.0%) were obtained using 1.0 to 2.0 mass% CaCN_2 addition depending on sintering temperature and time. All of the sintered samples exclusively belong to the same AIN phase, and no other phases were found in the X-ray diffraction (XRD) patterns. A large fraction of intergranular fracture was found in the AIN samples sintered without and with CaCN_2 additive in the scanning electron microscope (SEM) observations. The characterization of the ultrafine AIN powders sintered with CaCN_2 additive was performed with a microstructural analysis using a transmission electron microscope (TEM) attached with an energy-dispersive X-ray analyzer (EDX) and electron diffraction (ED). Both microstructural results and sintering behavior in the AIN-CaCN_2 system arise from the interaction between the Al_2O_3 surface covering the ultrafine AIN particles and the CaCN_2 additive. Most oxygen impurity are removed from AIN as CO or CO_2 gas and the residual oxygen impurity reacts to form the 3CaO・Al_2O_3 phase, which is found at the grain boundaries.
社団法人日本セラミックス協会の論文
2000-10-01