Thermal Expansion of Sintered Glass Ceramics in the System BaO–SrO–ZnO–SiO2 and Its Dependence on Particle Size

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• 作者：Christian Thieme ; Martin Schlesier ; Christian Bocker ; Gabriel Buzatto de Souza ; Christian Rüssel
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：August 10, 2016
• 年：2016
• 卷：8
• 期：31
• 页码：20212-20219
• 全文大小：553K
• 年卷期：0
• ISSN：1944-8252

文摘

The thermal expansion behavior of sintered glass-ceramics containing high concentrations of Ba_1–xSr_xZn₂Si₂O₇, a phase with very low and highly anisotropic thermal expansion behavior, was investigated. The observed phase has the crystal structure of the high-temperature phase of BaZn₂Si₂O₇, which can be stabilized by the introduction of Sr²⁺ into this phase. The high anisotropy leads to microcracking within the volume of the samples, which strongly affects the dilatometric thermal expansion. However, these cracks also have an influence on the nominal thermal expansion of the as-mentioned phase, which decreases if the cracks appear. Below a grain size of approximately 80 μm, the sintered glass-ceramics have almost no cracks and show positive thermal expansion. Hence, coefficients of thermal expansion between −5.6 and 6.5 × 10^–6 K^–1 were measured. In addition to dilatometric studies, the effect of the microstructure on the thermal expansion was also measured using in situ X-ray diffraction at temperatures up to 1000 °C.