Y_2O_3和TiO_2烧结剂对制备β-Sialon陶瓷烧结性能的影响

Effects of Y_2O_3 and TiO_2 as sintering additive on sintering properties of β-Sialon ceramic

以金属Al粉、单质Si粉、α-Al_2O_3微粉为主要原料,高温氮化反应制备β-Sialon陶瓷。通过在反应物中分别添加不同含量的Y_2O_3和TiO_2烧结剂,研究分析和对比了Y^(3+)和Ti^(4+)对β-Sialon陶瓷晶相组成、晶格常数、微观结构及烧结性能的影响。采用SEM及EDS对试样的微观形貌进行观察与分析,利用X'Pert Plus软件分析晶相的晶格常数,采用半定量法计算试样晶相组成。结果表明:Y_2O_3和TiO_2可显著降低高温氮化法制备β-Sialon陶瓷试样中β-Sialon相的生成温度。伴随着Y_2O_3和TiO_2的引入,Al_2O_3在Si3N4中的固溶度提高,β-Sialon晶相的生成量增加,晶格常数和晶胞体积增大,烧结性能得到改善。综合对比分析,Y_2O_3和TiO_2均对制备β-Sialon陶瓷具有良好的促烧结作用,用成本较低的TiO_2代替传统的稀土氧化物作为助烧结剂无压烧结制备β-Sialon陶瓷是可行的。

β-Sialon ceramic was prepared by high temperature nitriding reaction of raw material including Al metal powder,Si powder andα-Al_2O_3 fine powder.Adding different mass fractions of Y_2O_3 and TiO_2as sintering additive,the effect of Y3＋and Ti 4＋on the composition,lattice parameters,sintering properties and microstructure of crystalline phases was studied and compared.The crystalline phases and microstructure were determined by XRD and SEM,respectively.The lattice parameters of the crystalline phases were estimated by X＇Pert Plus software.The phase composition was evaluated by semi-quantification method.The results show that the addition of Y_2O_3 and TiO_2 makes the formation temperature ofβ-Sialon lower obviously.Adding of Y_2O_3 and TiO_2has a beneficial effect on the solid solubility of Al_2O_3 dissolving into Si3N4,the content and the lattice parameters ofβ-Sialon phase increase and the sintering properties are improved.Comprehensive analysis shows that Y_2O_3 and TiO_2 promote the sintering properties ofβ-Sialon ceramic,the formation of pressureless sinteredβ-Sialon ceramic is possible using low cost TiO_2 powder instead of the conventional rare earth as sintering additives.