Influence of in situ phase formation on properties of calcium zirconate refractories

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• 作者：Stefan Schaffö ; ner ; ^{stefan.schaffoener@ikgb.tu-freiberg.de" class="auth_mail" title="E-mail the corresponding author} ; Jens Fruhstorfer ; Christina Faß ; auer ; Lisa Freitag ; Constantin Jahn ; Christos G. Aneziris
• 关键词：Calcium zirconate ; Refractories ; Thermal shock resistance ; Elastic properties ; Thermal expansion coefficient
• 刊名：Journal of the European Ceramic Society
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：37
• 期：1
• 页码：305-313
• 全文大小：2071 K

文摘

This study investigates chemical, physical, mechanical, and thermomechanical properties of calcium zirconate (CaZrO₃) refractories. The applied fused raw material contained some residual cubic zirconia, which impairs the corrosion resistance of CaZrO₃ refractories. To adjust the stoichiometry, CaCO₃ was added. Furthermore, stoichiometric amounts of CaCO₃/monoclinic ZrO₂ were added to promote an in situ pore formation without altering the phase composition. After firing cubic zirconia was only found in the coarse grained aggregates. CaCO₃ additions increased the apparent porosity and reduced the thermal expansion coefficient due to the stoichiometric adjustment. Surprisingly, a higher porosity did not result in an improved thermal shock resistance, which can be attributed to a shift to larger pore sizes. This might cause a lower crack density, which is usually associated with a reduced thermal shock resistance. Future work will address the formation of smaller pores and the evaluation of the thermal shock resistance under practical conditions.