Li_2O-SiO_2系ガラスの結晶化に及ぼすK_2Oの効果

概要

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The effect of a small amount of K_2O on the crystallization behavior of the system of Li_2O-SiO_2 glass was investigated. Lithium disilicate (Li_2O・2SiO_2; L・2S) and lithium metasilicate (Li_2O・SiO_2; L・S) crystals precipitate simultaneously, but only L・2S crystals grow upon further heat treatment in the glass without K_2O (Li glass). In the glass containing K_2O (K3 glass), only L・S crystals precipitate and grow. The stable crystalline phases are L・2S and SiO_2 crystals in both glasses. Phase separation was observed before crystallization; a Li_2O-rich phase formed an isolated droplet phase in Li glass and the continuous phase in K3 glass. The Li^+-K^+ ion exchange test confirmed these structures. [SEM-EDX] analysis confirmed that K_2O exists in the Li_2O rich phase after phase separation in K3 glass. Thus, K3 glass separates into two phases, one of which is a continuous phase rich in Li_2O and containing considerable amount of K_2O. The L・S crystal precipitates and grows in this phase upon further heat treatment. Consequently, K_2O suppresses the crystallization of L・2S and promotes the precipitation of L・S crystals.
社団法人日本セラミックス協会の論文
2006-02-01