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采用热力学平衡方法,以1227℃为例,计算了硼化锆(ZrB_2)和碳化硅(SiC)的挥发相图,并由此例构建了硼化锆-碳化硅复合材料(ZrB_2-SiC)的挥发相图。在1.01×105Pa条件下,计算得到ZrB_2和SiC发生氧化的平衡分压logPO_2分别为-15.01Pa和-17.04Pa。结果表明,氧气分压会对ZrB_2、SiC和ZrB_2-SiC的氧化行为产生重要影响。随着氧分压升高,ZrB_2主要气相氧化产物的分压增加,SiC主要气相氧化产物的分压先增加后减小。对ZrB_2-SiC而言,随着氧分压的增大,在1227℃时体系中的主要气相产物转变序列为SiO(g)→B_2O_3(g)→BO_2(g)。
Using the thermodynamic equilibrium method, taking 1227 ℃ as an example, the volatilization phase diagram of ZrB2 and SiC was calculated, and the zirconium diboride-silicon carbide composite (ZrB2-SiC) Volatile phase diagram. Under the condition of 1.01 × 10 5 Pa, the equilibrium partial pressures logPO 2 of oxidation of ZrB 2 and SiC were calculated to be -15.01 Pa and -17.04 Pa, respectively. The results show that the oxygen partial pressure will have a significant impact on the oxidation behavior of ZrB_2, SiC and ZrB_2-SiC. With the increase of partial pressure of oxygen, the partial pressure of main oxidation products of ZrB 2 increased and the partial pressure of the oxidation products of SiC increased first and then decreased. For ZrB_2-SiC, with the increase of partial pressure of oxygen, the transformation sequence of the main products in the system at 1227 ℃ is SiO (g) → B_2O_3 (g) → BO_2 (g).