Y_2O_3对高温氮化反应制备Mg-α-Sialon陶瓷的影响

Effect of Y_2O_3 on Preparation of Mg-α-Sialon Ceramics by High Temperature Nitridation

在烧结镁砂中加入金属Al粉,单质Si粉和α-Al_2O_3微粉,以Y_2O_3为助烧结剂,经1550℃高温氮化反应可以合成Mg-α-Sialon相。研究了Y_2O_3加入量不同对Mg-α-sialon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:随着Y_2O_3含量的提高,Mg-α-Sialon相晶格常数、晶胞体积不断增大。固溶体YAG的形成降低了Mg-α-Sialon的合成温度,促进了氮化反应的进行。当加入5%的Y_2O_3时,Mg-α-Sialon相的晶胞体积达到了最大值0.333430 nm^3,形成了较为完整的棱柱状和板状的晶体结构,试样的氮化率达到了15.12%。

Mg-α-Sialon material was synthesized by nitridation at 1550 ℃, using AI, Si and ct-Al2O3 doped magnesite clinker as raw material, and Y2O3 as sintering aid. The effects of different amounts of Y2O3 on the composition and microstructure of Mg-α-sialon ceramics were studied by XRD, SEM and EDS. Results showed that with the increase of Y2O3 content, the lattice constant and cell volume of Mg-α-Sialon phase increased. The formation of YAG solid solution facilitated the nitridation by lowering the synthesis temperature of Mg-α-Sialon. When 5% of Y2O3 was doped, the cell volume of Mg-a-Sialon phase reached the maximum of 0.333430 nm3 with the formation of complete rod- and plate-like crystals, and the nitridation rate of the samples was up to 15.12%.