ABSTRACT Thermal shock resistance of precursor derived Si-Hf-C-N(O) foams at temperatures varying from 800o-1000oC subjected to multiple thermal cycles was investigated. The as-synthesized foams possessed interconnected pores with an average cell size of 1.09 mm. The X-ray diffractograms of the foams before and after thermal cycling showed that the amorphous nature of the foams was retained. FTIR spectra exhibited that there was no change in the bonding characteristics due to thermal shock. A damage parameter (DS) based on the compressive strength was used to quantify the extent of damage. Densification was expected to occur in the first thermal cycle and the strut structures did not show any sign of cracking. However, cracking of struts occurred in the third thermal cycle which caused severe damage. GRAPHICAL ABSTRACT

中文翻译：

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前驱体衍生的 Si-Hf-CN(O) 泡沫的抗热震性

摘要 研究了前体衍生的 Si-Hf-CN(O) 泡沫在 800o-1000oC 的温度下经受多次热循环的抗热震性。合成的泡沫具有相互连接的孔，平均孔径为 1.09 毫米。热循环前后泡沫的 X 射线衍射图表明，泡沫的无定形性质得以保留。FTIR 光谱表明，由于热冲击，粘合特性没有变化。基于抗压强度的损伤参数 (DS) 用于量化损伤程度。预计在第一次热循环中会发生致密化，并且支柱结构没有出现任何开裂迹象。然而，在第三次热循环中发生了支柱的开裂，造成了严重的破坏。图形概要