Characteristics of thermal transformations of oligomeric silazanes with organoelement substituents at the N atoms (M-OESs) containing one element M = Y, Zr, or Hf or a pair of elements, viz., Zr and Y or Hf and Y, in air in the temperature range 200–1500 °C were investigated. The introduction of yttrium into zirconium- or hafnium-containing oligosilazanes results in an increase in the mass loss at the stage of ceramization and to a decrease in the mass loss in the formed ceramics during subsequent stepwise heat treatment up to 1500 °C. The combination of yttrium with hafnium or zirconium in M-OESs results in a synergistic effect of overall mass loss reduction. The (Zr, Y)-OES and (Hf, Y)-OES multiceramics outperform ceramics modified with one metal in this parameter. The obtained multiceramics is characterized by high thermo-oxidative stability in the temperature range 1100–1500 °C. It is also found that yttrium-containing oligosilazane (Zr, Y)-OES exhibits oleophilic properties with respect to carbon materials.

中文翻译：

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含有有机元素取代基的低聚硅氮烷和基于它们的多陶瓷的钇的热氧化稳定性

含有一个元素 M = Y、Zr 或 Hf 或一对元素，即 Zr 和 Y 或 Hf 和 Y，在空气中的 N 原子处具有有机元素取代基的低聚硅氮烷 (M-OES) 的热转化特征研究了 200–1500 °C 的温度范围。将钇引入含锆或铪的低聚硅氮烷会导致陶瓷化阶段的质量损失增加，并在随后的高达 1500°C 的逐步热处理过程中减少所形成陶瓷的质量损失。钇与铪或锆在 M-OES 中的组合导致整体质量损失减少的协同效应。(Zr, Y)-OES 和 (Hf, Y)-OES 多晶陶瓷在该参数中优于用一种金属改性的陶瓷。所获得的陶瓷在 1100-1500°C 的温度范围内具有较高的热氧化稳定性。还发现含钇的低聚硅氮烷 (Zr, Y)-OES 对碳材料表现出亲油性。