摘要
ZrO_2是一种重要的结构和功能材料,其热膨胀系数与Zr W2O8的负膨胀系数绝对值相近,两者合理调配可以得到任意正、零、负膨胀的陶瓷基复合材料。以ZrO_2陶瓷为基体、Al2O3为烧结助剂,采用两条工艺路线制备ZrO_2/Zr W2O8陶瓷基复合材料:(1)以ZrO_2和Zr W2O8为原料,直接混合然后分别在1200℃和1215℃热压烧结制备复合材料;(2)以ZrO_2(过量)和WO3为原料,采用原位反应法分别在1200℃和1215℃合成负膨胀Zr W2O8陶瓷,然后在相同温度下热压烧结制备复合材料。重点研究不同制备工艺路线(直接混料法或原位反应法+热压烧结),以及在同一种制备方法下、不同热压烧结温度对低膨胀ZrO_2/Zr W2O8陶瓷基复合材料组织形貌、密度和Zr W2O8分解程度的影响。结果表明,无论采用哪种工艺路线,都能制备密度较高的ZrO_2/Zr W2O8陶瓷基复合材料。采用"原位反应+热压烧结法"制备复合材料的密度要高于"直接混料+热压烧结法"制备的复合材料;且Zr W2O8分解程度也较低。直接混料粉在1200℃热压3 h,或者在1215℃热压6 h,所得复合材料的密度约为5.20 g/cm3。
ZrO_2 is one kind of structure and function materials, and its heat expansion coefficient is similar to the absolute value of the negative expansion coefficient(NEC) in Zr W_2O_8 ceramics. So, the ceramic matrix composites with the positive, zero or negative expansion coefficient can be got by mixing them precisely. In this work, the ZrO_2/Zr W_2O_8 ceramic matrix composites(ZrO_2 as the matrix and Al2O3 as the sintering additive) have been prepared by two different processes:(1) with WO3 and Zr W_2O_8 as raw powders, the ZrO_2/Zr W_2O_8 composites, after mixed ZrO_2 and Zr W_2O_8 directly, were prepared by heat-pressing sintering at 1200 °C and 1215 °C.(2) The ZrO_2/Zr W_2O_8 composites, after Zr W_2O_8 were made by in-situ reaction of ZrO_2 and WO3 raw powders, were prepared by heat-pressing sintering at 1200 °C and 1215 °C. The microstructure, density and the Zr W_2O_8 decomposition degree were compared among the sintered samples fabricated by the above two different methods, and the effects of different sintering temperatures within the same preparation method were also investigated. The results show that ZrO_2/Zr W_2O_8 ceramic matrix composites with high density can be prepared by either of the two different methods. The final density of the composites made by in-situ reaction is higher than that of the composites made by direct mixing, while the Zr W_2O_8 decomposition degree is lower. The ZrO_2/Zr W_2O_8 ceramic matrix composites with density 5.20 g/cm3 can be prepared by the heat-pressing sintering at 1200 °C for 3 h or at 1215 °C for 6 h after mixed directly ZrO_2 and Zr W_2O_8 raw powders.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2015年第S1期311-315,共5页
Rare Metal Materials and Engineering
基金
航天支撑技术基金
