中文摘要：

利用烧结镁砂中固有杂质,加入金属Al粉、单质Si粉和α-Al2O3微粉,以Y2O3为助烧结剂,经氮化烧结炉1550℃氮化烧结1 h制备出Mg-α/β-sialon复相陶瓷,实现镁质材料的性能改进和优化。研究了不同Y2O3加入量对Mg-α/β-sialon复相陶瓷的矿物组成及微观形貌的影响,借助于XRD分析试样中的晶相组成和晶胞参数,采用SEM及EDS对试样断口的微观形貌进行分析与观察。结果表明：Mg-α/β-sialon复相陶瓷以β-sialon为主晶相,Mg-α-sialon为次晶相。随着Y2O3加入量的增加,Mg-α-sialon相的生成量呈减小趋势,β-sialon相的生成量呈增加趋势,Mg-α-sialon的形貌由短柱状向长棱柱状转变,当Y2O3加入5wt%时为片状结构。Y3＋的引入使Mg-α/β-sialon相晶格变形,增加了缺陷浓度,提高了阴阳离子的自扩散能力,促进氮化烧结反应的进行。

英文摘要：

Mg-α / β-sialon composites were synthesized by self-diffusion nitridation reaction in flowing nitrogen atmosphere at 1550 ℃ for 1 hour. In the synthesis,the sintered magnesia with its original impurities, Al metal powders, Si powders and α-Al2O3 fine powder were employed as main raw materials,and Y2O3 was used as the additive. The synthesis method has potential to be a promising technique to optimize mechanical and thermal properties of magnesia material. The effect of Y2O3 addition on microstructure and mineral composition of synthesized Mg-α / β-sialon composites were Studied. The crystal phase composition and lattice parameters were estimated by X ＇Pert plus software. The fracture morphology was identified via SEM and EDS respectively. The results show that β-sialon is the main crystal phase in the Mg-α / β-sialon composites,and the Mg-α-sialon is a secondary phase. β-sialon phase increases whereas Mg-α-sialon phase decreases with the adding quantity of Y2O3 increasing,and the morphology of Mg-α-sialon varies from short column to long prism,and transforms further into lamellar structure as Y2O3 addition reaches 5wt%. Doping of Y3 ＋leads to lattice deformation,thusincreases defects concentration,enhances the self-diffusion ability of anions and cations and promotes sintering.