Li_2O-MgO-Al_2O_3-SiO_2系ガラス結晶化物の誘電損失について

概要

論文の詳細を見る
In the previous paper (J. Ceram. Assoc. Japan, 68 [10] 223 1960)) the authors have given the method of converting the glasses of the system Li2O-MgO-Al2O3-SiO2 into a polycrystalline material with or without the addition of platinum nucleus, the amount of which was limited to a very small value. The results of the measurement of the mechanical and thermal properties of the material produced were also published (J. Ceram. Assoc., Japan, 69 [2] 35 (1961)). The present paper concerns the dielectric loss of the same material which was expected to show the effect of chemical composition and heat treatment.(1) Effect of heat treatmentThe glass of the composition, MgO 15, Al2O3 23, SiO2 62, Li2Ox, where x=4, 6, 8, 12 by weight ratio, were melted, and reheated with the constant rate of 5°C/min. to a temperature from 750° to 1200°C.The tan δ at 1 Mc of the crystallized specimens (cf. Fig. 1) showed that, in general, it became higher than the base glass by the heat treatment at a temperature between 750° and 950°C, whereas the heating at a temperature higher than 1000°C brought about a great decrease in tan δ.The increase of tan δ may be attributed to the formation of β-eucriptite which usually occurs in the low temperature range, while the sudden decrease in tan δ may be attributed to the formation of β-spodumen which appears with the cost of vanishing β-eucryptite.(2) Effect of the chemical composition of the base glassIt is likely that the amount of platinum, 0.01%, was too small to have an effect on tan δ, and also the cardinal component of base glass, such as MgO, Al2O3 and SiO2 behaved themselves rather indifferent. On the contrary, Li2O showed a strong influence, and the decrease of Li2O content seemed to be especially fovourable for the formation of β-spodumen and consequently the lowering of tan δ.(3) Effect of additional componentsThe glasses of the base composition, Li2O 4, MgO 15, Al2O3 15, and SiO2 62 by weight, and added by a small amount of any of the components, Na2O, K2O, BeO, CaO, SrO, ZnO, CdO or PbO were melted and reheated at above 950°C. Among such second components PhO was the most effective, giving tan δ of 3-4×10-4 at 1 Mc at room temperaure with the addition of PbO: 0.045mols to 104g of the base glass (cf. Fig. 4).
1961-11-01

Li_2O-MgO-Al_2O_3-SiO_2系ガラス結晶化物の誘電損失について

スポンサーリンク

概要

著者

関連論文

スポンサーリンク