低熱膨張性リン酸ジルコニルセラミック : 粒成長の抑制とジルコンとの複合

概要

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Ceramics with high-strength and low-thermal-expansion-coefficient was prepared from (ZrO)_2P_2O_7. Overfiring reduced the strength, because the extensive grain growth developed microcracks due to the thermal expansion anisotropy of the crystal. The effects of additives on the densification and grain growth were studied at high temperature. Above 1500℃, the densification was promoted by adding TiO_2. The maximum strength of this ceramic was about 50 MPa. SiO_2 was effective in suppressing grain growth responsible for the microcracking. Thus, a ceramic which has a strength of 150 MPa was obtained by adding SiO_2 together with sintering aid such as MgO and Nb_2O_5 even after firing at 1500℃. Composites in the system (ZrO)_2P_2O_7-ZrSiO_4 with TiO_2 additive had the strength of 200 MPa and thermal expansion coefficient from 1.7 to 4.0X10^<-6>/℃.
1989-04-01