Abstract This study investigated the cold isostatic pressing of coarse grained alumina refractories applying either a cyclic pressure increase or a cycling at maximum pressure. Additionally the effects of the maximum pressure and the particle size distribution on physical, mechanical and thermomechanical properties were analyzed. The cyclic pressure increase resulted in a slightly higher apparent density and lower apparent porosity. A cycling at maximum pressure decreased the median pore size to some extent. Remarkably, an optimized particle size distribution resulted in a lower apparent porosity, lower median pore size and in a higher Young's modulus before and after thermal shock together with a slightly lower relative decrease of the Young's modulus. A higher pressing pressure which decreased the apparent porosity did not affect the Young's modulus. Thus, apparently the optimized particle size distribution improved the particle packing which was associated with a smaller median pore size. This smaller pore size increased the number of pores relative to the total porosity, which then acted as points of crack initiation and crack deflection limiting the length of propagating cracks in case of thermal shock. Thus, tailoring the pore size distribution is a promising starting point to improve the thermomechanical properties of refractories.

中文翻译：

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用于耐火材料的粗粒氧化物陶瓷的循环冷等静压和改进的颗粒填充

摘要 本研究调查了粗粒氧化铝耐火材料的冷等静压，应用循环压力增加或最大压力循环。此外，还分析了最大压力和粒度分布对物理、机械和热机械性能的影响。循环压力增加导致略高的表观密度和较低的表观孔隙率。在最大压力下循环在一定程度上降低了中值孔径。值得注意的是，优化的粒度分布导致较低的表观孔隙率、较低的中值孔径和较高的杨氏模量，同时杨氏模量的相对下降幅度略低。降低表观孔隙率的较高压制压力不会影响杨氏模量。因此，显然优化的粒度分布改善了与较小的中值孔径相关的颗粒堆积。这种较小的孔径增加了相对于总孔隙率的孔隙数量，然后作为裂纹萌生点和裂纹偏转点，在热冲击的情况下限制了裂纹扩展的长度。因此，调整孔径分布是改善耐火材料热机械性能的一个有希望的起点。然后作为裂纹萌生点和裂纹偏转点，在热冲击的情况下限制了裂纹扩展的长度。因此，调整孔径分布是改善耐火材料热机械性能的一个有希望的起点。然后作为裂纹萌生点和裂纹偏转点，在热冲击的情况下限制了裂纹扩展的长度。因此，调整孔径分布是改善耐火材料热机械性能的一个有希望的起点。