Thermal and Mechanical Properties of Unidirectionally Solidified Li<sub>2</sub>O⋅2SiO<sub>2</sub> Ceramics

DOI Web Site Web Site Open Access

Bibliographic Information

Other Title
  • 融液の一方向凝固により得られるＬｉ?S２?TＯ・２ＳｉＯ?S２?T多結晶体の熱的，機械的性質
  • ユウエキ ノ 1ホウコウ ギョウコ ニ ヨリ エラレル Li2O 2SiO2

Search this article

Description

Melts of the compositions, Li2O⋅2SiO2 and 100 (Li2O⋅2SiO2)⋅3RxOy, where RxOy is B2O3, Na2O, MgO, Al2O3, SiO2 or P2O5, were unidirectionally solidified by the thermal gradient furnace method (Ref. Yogyo-Kyokai-Shi, 85, 501 (1977)). The solidified ingots were composed mainly of columnar Li2O⋅2SiO2 crystals of 170-580μm in diameter, elongating parallel to their c-axes. Thermal expansions of the ingots in the direction of their crystal elongation (//) agreed with that of the c-axis of a Li2O⋅2SiO2 single crystal, irrespective of their solidification rates and compositions. Their expansions in the direction perpendicular to their crystal elongation (⊥), however, markedly differed from the mean value of a- and b-axes of the Li2O⋅2SiO2 single crystal, being dependent on their solidification rates and compositions. Propagation rates of a 12MHz longitudinal sound wave in the ingots along the direction (//) showed a constant value of 7.2km/s, irrespective of their porosity, whereas those along the direction (⊥) decreased markedly with increasing porosity. The compressive strengths (s) of the ingots in the direction (//) little decreased with increasing porosity (p), whereas those in the direction (⊥) decreased markedly on the equation s∝exp (-25p). These anisotropic properties of the ingots were interpreted in terms of their microstructure; i.e. of the continuity of the Li2O⋅2SiO2 columnar crystals, and the presence of the other crystals, glassy phase and pores among the columnar crystals.

Journal

Keywords

Details 詳細情報について

Report a problem

Back to top