恒温环境中ZrB2氧化行为模拟  

Simulation of ZrB2 Oxidation Behavior at Constant Temperature Ambient

作　　者：周述光[1,2] 国义军[2] 刘骁[2] ZHOU Shu-Guang;GUO Yi-Jun;LIU Xiao(State Key Laboratory of Aerodynamics,China Aerodynamics Research and Development Center,Mianyang 621000,China;Computational Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China)

机构地区：[1]中国空气动力研究与发展中心空气动力学国家重点实验室,绵阳621000 [2]中国空气动力研究与发展中心计算空气动力研究所,绵阳621000

出　　处：《无机材料学报》2019年第6期660-666,共7页Journal of Inorganic Materials

基　　金：国家重点基础研究发展计划(2014CB744100)~~

摘　　要：二硼化锆(ZrB2)是一种应用于高超声速飞行器的新型防热材料,近年来受到广泛关注。本研究根据ZrB2在不同温度下的氧化产物二氧化锆(ZrO2)与三氧化二硼(B2O3)的微观结构和形貌,改进了原有的ZrB2氧化唯象模型,研究了ZrB2的氧化行为,提出了中等温度区间液态B2O3的生成、蒸发、填充的动态平衡关系,并考虑了孔隙出口处的B2O3蒸气浓度。研究结果表明:改进后的模型能够预测低流速准静态条件下ZrB2的氧化行为,与加热炉中的样品恒温氧化测试结果吻合良好;孔隙对氧化过程有较大影响,在相同的温度、氧分压下,孔隙率越大,被氧化程度越高;在基材表面存在B2O3液态膜的情况下,扩散过程对氧化速率的控制被极大地降低,材料表现出最强的抗氧化性能。Zirconium diboride (ZrB2), a thermal protection material for hypersonic vehicle, has received widespread attention in recent years. Here we advance an oxidation model based on oxidation products (ZrO2 and B2O3) and their morphology at different temperatures to simulate the oxidation behavior of ZrB2. This study further establishes the dynamic equilibrium among formation, evaporation and supplement of B2O3 whose concentration at ambient was assumed to be nonzero. Research results indicate that the advanced model can predict the oxidation behavior of ZrB2 under quasi-static low flow conditions and the simulation results are consistent with the data obtained from sample suspended in wire heater furnace at constant temperature. The porosity has a great influence on the oxidation process, and at the same temperature and oxygen partial pressure, the larger the porosity, the higher the oxidation degree. The oxidation rate controlled by diffusion in the presence of liquid B2O3 film laying outer surface of substrate reduces greatly and the material exhibits the strongest oxidation resistance.

关 键 词：二硼化锆 氧化行为 孔隙率 模拟 液态膜 

分 类 号：V45[一般工业技术—材料科学与工程]