Theoretical and experimental analyses of relationship between processing and thermal conductivity of SiC with oxide additives
Theoretical and experimental analyses of relationship between processing and thermal conductivity of SiC with oxide additives
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DOI：
10.1016/j.ceramint.2016.05.156
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发表时间：
2016-09
影响因子：
5.2
通讯作者：
Y. Hirata;H. Shirai;Ryo Ando;Yukako Matsumoto;T. Shimonosono
中科院分区：
文献类型：
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作者：
Y. Hirata;H. Shirai;Ryo Ando;Yukako Matsumoto;T. Shimonosono
本文从理论和实验两方面分析了SiC-氧化物添加剂-气孔系统的导热性能。在开发的6个模型结构中，计算了含氧化物的SiC压坯的热导率（κB）作为SiC、氧化物添加剂和孔隙的体积分数的函数。计算得到的κ b值按连续相的顺序减小，在连续相中分散着另外两种颗粒相：SiC>氧化物添加剂>孔隙。用两种氧化物连续相模型计算的κ b值较好地解释了添加4-50 mass%氧化物（33.3mass % Al_2O_3 - 33.3mass % Y_2O_3 - 33.3mass % SiO_2的混合物）热压SiC压坯的κ b值。在1950 °C热压的SiC压坯中，仅SiC颗粒的热导率也在所开发的两个模型结构中使用测量的κB（氧化物连续相模型和SiC连续相模型）在理论上估算，其中热压的SiC压坯具有4质量%的Al 2 O3、Y2 O3、SiO2、Al 2 O3-Y2 O3、Y2 O3-SiO2和Al 2 O3-Y2 O3-SiO2。根据计算结果，确定了获得高κB的关键因素：（1）高的烧结密度;（2）少量的具有高热导率的氧化物添加剂;（3）在凝固过程中不使液相中的杂质原子溶解到SiC晶粒中。
This paper analyzes theoretically and experimentally the thermal conductivity of the SiC-oxide additive-pore system. In the developed 6 model structures, the thermal conductivity of an SiC compact (κb) with oxide was calculated as functions of the volume fractions of SiC, oxide additive and pores. The calculated κbdecreases in the order of a continuous phase where the other two particulate phases are dispersed: SiC>oxide additive>pores. The measured κbvalues of SiC compacts hot-pressed with 4–50 mass% oxide additive (mixture of 33.3 mass% Al2O3-33.3 mass% Y2O3-33.3 mass% SiO2) were well explained by the calculated κbin two types of oxide continuous phase models. The thermal conductivities for only SiC grains in SiC compacts hot-pressed with 4 mass% Al2O3, Y2O3, SiO2, Al2O3-Y2O3, Y2O3-SiO2and Al2O3-Y2O3-SiO2at 1950 °C were also estimated theoretically in the developed two model structures using the measured κb(oxide continuous phase model and SiC continuous phase model). Based on the calculated results, the following key factors are identified to achieve a high κb: (1) high sintered density, (2) a small amount of oxide additive with a high thermal conductivity, (3) no dissolution of foreign atoms from a liquid phase into SiC grains during solidification process.