Abstract

Specific features of the synthesis of sialons (SiAlON) in the Si–Al–O–N system by firing at 1600–1700°C in a nitrogen atmosphere of mixtures of different initial compositions corresponding to the same composition of the final product Si₃Al₃O₃N₅ have been studied. β-Sialon was synthesized from reaction mixtures based on crystalline silicon and aluminum nitrides and amorphous highly dispersed hydrated oxides—(1) AlN + SiO₂(sol), (2) Si₃N₄ + Al₂O₃(sol), and (3) AlN + Si₃N₄ + Al₂O₃(sol)—obtained by applying sols based on silicon or aluminum alkoxides (based on the β-sialon stoichiometry) to the surface of nitride powders by the sol-gel method. It has been demonstrated that β-Si₃Al₃O₃N₅ can form in the reaction at 1600°C of highly dispersed mixed xerogels made of silicon and aluminum alkoxides—(4) (SiO₂ + Al₂O₃) (mixed sol)—with molecular nitrogen without the participation of the initial nitrides. The influence of the starting composition of xerogel mixtures and synthesis conditions on the phase composition and morphological features of sialons obtained in one stage of calcination in a nitrogen atmosphere has been studied by thermogravimetry, X-ray powder diffraction analysis, and electron microscopy. It has been shown that the proposed reactions of the formation of sialons involving crystalline nitrides, xerogels, and molecular nitrogen are related to reduction–nitridation reactions, in which the reducing agents are organic products of hydrolysis of silicon and aluminum alkoxides and their pyrolytic decomposition in a nitrogen atmosphere.

中文翻译：

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氧化三氮铝硅酸盐（SiAlON）的溶胶-凝胶合成

摘要

Si–Al–O–N系统中通过在氮气氛中于1600–1700°C烧制不同初始组成的混合物（对应于最终产品Si ₃ Al的相同组成）的混合物来合成赛隆（SiAlON）的特定特征已经研究了₃ O ₃ N ₅。β-Sialon是由基于结晶硅和氮化铝以及非晶态高度分散的水合氧化物的反应混合物合成的：（1）AlN + SiO ₂（sol），（2）Si ₃ N ₄ + Al ₂ O ₃（sol）和（3）AlN + Si ₃ N ₄ + Al ₂ O ₃（溶胶）-通过溶胶-凝胶法将基于硅或铝醇盐的溶胶（基于β-赛隆化学计量法）施加到氮化物粉末的表面而获得。已经证明的是β型Si ₃的Al ₃ ö ₃ Ñ ₅可以在alkoxides-（4）（SIO由硅和铝的高度分散的混合干凝胶的1600℃的反应形成₂ +的Al ₂ ö ₃）（混合溶胶）-含分子氮而没有初始氮化物的参与。通过热重分析，X射线粉末衍射分析和电子显微镜研究了干凝胶混合物的起始组成和合成条件对在氮气氛中煅烧的一个阶段中获得的唾液酸的相组成和形态特征的影响。结果表明，所建议的涉及结晶氮化物，干凝胶和分子氮的唾液酸形成反应与还原-氮化反应有关，其中还原剂是硅和铝的醇盐水解及其在铝中的热分解的有机产物。氮气氛。