Creep behavior of Si3N4 polycrystals containing Y2O3-MgO-SiO2 glass phase (with and without calcuium oxide [CaO] additive) was studied by compression tests between 1500 and 1700oC. We studied the effect of CaO additives on flow stress, microstructural evolutions, and thermal stability of the intergranular glass phase during deformation. While the addition of CaO did not affect grain size, the flow stress decreased with the amount of CaO. This result suggested that the addition of CaO reduced the viscocity of intergranular glass phase. The addition of CaO further improved the thermal stability of the glass phase by supressing the evaporation at elevated temperatures.
各種検索
サポート
ヘルプ