稀土氧化物对氧化反应结合碳化硅陶瓷性能的影响

利用氧化反应结合工艺,从物相组成、氧化行为、致密化、力学性能和显微结构几个方面研究了将稀土氧化物(Y2O3、La2O3和CeO2)添加到SiC和Al2O3混合物中对SiC陶瓷的影响.结果表明,稀土氧化物的添加有利于氧化反应结合SiC陶瓷中莫来石相生成,使莫来石化温度下降了大约100℃;同时,稀土氧化物的添加不仅降低了反应结合SiC陶瓷的气孔率,还使其力学性能明显得到提高;在1300℃、保温2h烧结,4.5%-CeO2(质量分数)掺杂样品的气孔率下降到5%,抗弯强度达到150MPa.

Effect of Rare Earth Oxides Addition on Properties of Oxidation Reaction-bonded SiC Ceramics

Using oxidation reaction-bonded technology,the effect of rare earth oxides(Y2O3,La2O3 and CeO2 ) on phase composition,oxidation behavior,densification,mechanical property and microstructure of SiC ceramic are investigated.The results show that all three rare earth oxides addition exert an positive effect on the mullitization behavior,it reduces the mullite formation temperature by about 100℃.At the same time the rare earth oxides not only reduce the porosity of reaction-bonded SiC ceramics,but also significantly improve its mechanical property.The porosity of 4.5wt% CeO2-doped sample sintered at 1300℃ for 2h reduces to 5%,flexural strength reaches to 150MPa.