Abstract

The compaction of initial powders, the bending strength, and the microhardness of 21R sialon ceramics obtained by hot pressing have been studied experimentally. It is found that the Sm₂O₃ sintering additive substantially reduces the annealing temperature and enhances the properties of the ceramics. The samples of 21R sialon ceramics without additives, which are prepared by annealing at 1950°C, have a density of 3.01 g/cm³, a bending strength of 240 ± 15 MPa, and a Vickers microhardness of 16.2 ± 0.4 GPa; the samples of 21R sialon ceramics with 2.5 wt % Sm₂O₃, which are annealed at 1750°C, are characterized by a density of 3.39 g/cm³, a bending strength of 315 ± 16 MPa, and a Vickers microhardness of 21.9 ± 0.2 GPa. It is shown that Sm₂O₃ reacts with 21R sialon in the temperature range of 1600–1700°C to form the 27R sialon and SmAlO₃ impurity phases. In the samples annealed at 1750°C, the 27R sialon and Sm–sialon (Sm₃Si_2.5Al_3.5O_12.5N_1.5) impurity phases are detected.

中文翻译：

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含氧化钐添加剂的热压 2​​1R SiAlON 陶瓷的性能

摘要

对热压得到的21R赛隆陶瓷的初始粉末压实度、抗弯强度和显微硬度进行了实验研究。发现Sm ₂ O ₃烧结添加剂显着降低了退火温度并提高了陶瓷的性能。1950℃退火制备的无添加剂21R赛隆陶瓷样品，密度为3.01 g/cm ³，抗弯强度为240±15 MPa，维氏显微硬度为16.2±0.4 GPa；含有 2.5 wt% Sm ₂ O ₃的 21R 赛隆陶瓷样品在 1750°C 下退火，其特征在于密度为 3.39 g/cm ³，弯曲强度为 315 ± 16 MPa，维氏显微硬度为 21.9 ± 0.2 GPa。结果表明，Sm ₂ O ₃与 21R 赛隆在 1600-1700°C 的温度范围内反应形成 27R 赛隆和 SmAlO ₃杂质相。在 1750°C 退火的样品中，检测到 27R 赛隆和 Sm-赛隆（Sm ₃ Si _2.5 Al _3.5 O _12.5 N _1.5）杂质相。