Improvement of MoSi2 oxidation resistance via boron addition: Fabrication of MoB/MoSi2 composite by mechanical alloying and subsequent reactive sintering
Improvement of MoSi2 oxidation resistance via boron addition: Fabrication of MoB/MoSi2 composite by mechanical alloying and subsequent reactive sintering
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DOI：
10.1016/j.powtec.2014.01.034
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发表时间：
2014-03
影响因子：
5.2
通讯作者：
P. R. Taleghani;S. Bakhshi;M. Erfanmanesh;G. H. Borhani;R. Vafaei
中科院分区：
文献类型：
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作者：
P. R. Taleghani;S. Bakhshi;M. Erfanmanesh;G. H. Borhani;R. Vafaei
本研究的目的是确定添加硼对MoSi 2抗氧化性的影响。化学计量比为1：2的Mo-Si和30 Mo-47 Si-23 B（at.%）的粉末混合物分别制备了MoSi 2和MoB/MoSi 2。将第一粉末混合物在磨碎机球磨机中单独研磨20小时。在450 °C下对机械合金化的粉末进行脱气之后，在600 MPa的压力下将粉末压制成圆柱形样品。样品的最终直径为15 mm。压制的样品在管式电阻炉中使用Ar控制气氛烧结。分别在1300 °C保温3 h和1100 °C保温7 h烧结得到MoB/MoSi 2双相结构的30 Mo-47 Si-23 B合金和MoSi 2单块体。烧结合金在1000 °C下进行高温连续氧化试验。通过扫描电镜、能谱仪和X射线衍射仪对烧结合金和机械合金化粉末的显微组织、烧结和氧化样品的相组成进行了分析。结果表明，30 Mo-47 Si-23 B合金无粉化现象。在MoB/MoSi 2复合材料的氧化试验中，硼的存在对氧的扩散起到了有效的阻挡作用。MoB/MoSi 2复合材料的显微组织分布均匀，晶粒细小，相对密度高，具有良好的抗氧化性能。
The purpose of this study is to determine the influence of boron addition on the oxidation resistance of MoSi2. Powder mixtures of Mo–Si with stoichiometric ratio of 1:2 and 30Mo–47Si–23B (at.%) were used, respectively to produce MoSi2and MoB/MoSi2. First powder mixtures were separately milled for 20 h in an attritor ball mill. After degassing of as-mechanically alloyed powders at 450 °C, the powders were pressed into cylindrical samples under a pressure of 600 MPa. The final diameter of samples were 15 mm. Compacted samples were sintered in tube resistance furnace using Ar controlled atmosphere. 30Mo–47Si–23B alloy with a MoB/MoSi2two-phase structure and monolithic MoSi2were obtained by sintering at 1300 °C for 3 h and 1100 °C for 7 h, respectively. The sintered alloys were subjected to high temperature continuous oxidation test at 1000 °C. Microstructure of sintered alloys and as-mechanically alloyed powders, phase composition of sintered and oxidized samples were evaluated by scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. The results showed that in 30Mo–47Si–23B alloy no pest disintegration is observed. The presence of boron acted as an effective barrier against oxygen diffusion during oxidation test of MoB/MoSi2composite. Excellent oxidation resistance of MoB/MoSi2composite was achieved through homogeneously distributed and fine grained microstructure and also very high relative density.