温度・粘度
β-Wollastonite
Japanese: β-ウォラストナイト
A high-temperature, stable crystalline phase of CaSiO₃ that precipitates during the devitrification of soda-lime glass. It is one of the typical devitrification phases, along with DevitRite and α-cristobalite.
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β-Wollastonite (β-Wollastonite) is a high-temperature-stable polymorph of calcium silicate (CaSiO₃) and is one of the crystalline phases that precipitates during the devitrification of soda-lime glass (SLS) (treatise §7.1). Along with DevitRite (Na₂Ca₃Si₆O₁₆) and α-cristobalite (SiO₂), it is classified by Kilinc & Hand (2021) as a major devitrification phase in SLS glass. It tends to precipitate primarily during prolonged exposure to high temperatures of 800°C or higher and exhibits plate-like or fibrous crystal morphologies.
The main situations in which β-wallastonite precipitation becomes a problem in kiln work are when the flow into fine details is maintained for an extended period during high-temperature casting (800–900°C) or when the flow is held for an excessively long time during pot melting (810–820°C). When this precipitation occurs, transparency is compromised, and a milky white haze appears on the surface of the piece. Prevention involves passing through the devitrification range (600–900°C) in the shortest possible time (rapid heating and rapid cooling). Devitrite tends to precipitate at 660–800°C, while β-wallastonite tends to precipitate at 800°C or higher; the primary devitrification phase varies depending on the operating temperature range.
Related Concepts
devitrite（devitrite）・α-クリストバライト（alpha-cristobalite）・表面結晶化（surface-crystallization）・バルク結晶化（nucleation）・失透核（devit-nucleus）・4ゾーン（four-zones）
This entry is written in Japanese by Rei Chikaoka and translated for readers outside Japan. If something reads oddly, the original is the source of truth.