Unprecedented oxidation resistance at 900 °C of Mo–Si–B composite with addition of ZrB2
Unprecedented oxidation resistance at 900 °C of Mo–Si–B composite with addition of ZrB2
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添加 ZrB2 的 Mo-Si-B 复合材料在 900 °C 下具有前所未有的抗氧化性
DOI：
10.1016/j.ceramint.2020.02.264
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发表时间：
2020
影响因子：
5.2
通讯作者：
Guojun Zhang
中科院分区：
文献类型：
--
作者：
Juan Wang;Bin Li;Rui Li;Xuan Chen;Tao Wang;Guojun Zhang
研究了Mo-12Si-8.5B和Mo-12Si-8.5B-ZrB2复合材料在900℃空气中的氧化行为。Mo-12Si-8.5B复合材料在此低温下氧化30h，失重达180 mg/cm2。这在很大程度上归因于在其表面形成了低粘度的硼硅酸盐玻璃膜，这使得MoO_3能够连续蒸发。然而，在Mo-12Si-8.5B中加入ZrB2可以显著控制氧化程度，进一步显著提高复合材料的抗氧化性。其中，Mo-12Si-8.5B-ZrB2复合材料氧化30h后的增重率仅为10 mg/cm2，且氧化趋势稳定，与未氧化的复合材料的氧化行为相反。此外，在含ZrB_2的复合材料中还观察到硅酸盐氧化膜和内氧化层的厚度显著减小。由于ZrB_2的加入增加了石英玻璃的粘度，形成了一层保护性的富锆硅酸盐玻璃膜，并使复合材料免受进一步氧化的影响。此外，还生成了ZrO2/ZrSiO4产物，进一步阻止了Mo或Mo氧化物的蒸发，阻碍了氧的向内扩散。
The oxidation behavior of Mo–12Si-8.5B and Mo–12Si-8.5B–ZrB2composites was studied at 900 °C in air. The Mo–12Si-8.5B composite, presented the significant weight loss of 180 mg/cm2during oxidation for 30 h at this low temperature. This was largely attributed to the formation of low viscosity borosilicate glass scale on its surface, which allowed the continuous evaporation of MoO3. However, such degree of significant oxidation was controlled dramatically by the addition of ZrB2to the Mo–12Si-8.5B and it further significantly improved the oxidation resistance of the composite. In particular, the Mo–12Si-8.5B–ZrB2composite presented the small weight gain of 10 mg/cm2after oxidation for 30 h; moreover the oxidation trend of Mo–12Si-8.5B–ZrB2was stable and its behavior was opposed to that of the ZrB2-free composite. In addition, the drastically decreased thicknesses of the silicate scale and internal oxide layer were observed in the ZrB2-contained composite. Owing to the addition of ZrB2, which increased the viscosity of the silica glass, a protective Zr-rich silicate glass scale formed and passivated the composite against further oxidation. This was supplemented by the ZrO2/ZrSiO4products that further prevented the Mo or Mo oxides from evaporating and hindered the inward diffusion of oxygen.