Synthesis, microstructure and properties of MoAlB ceramics prepared by in situ reactive spark plasma sintering
Synthesis, microstructure and properties of MoAlB ceramics prepared by in situ reactive spark plasma sintering
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DOI：
10.1016/j.ceramint.2020.03.059
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发表时间：
2020-07
影响因子：
5.2
通讯作者：
Xiaojia Su;Jian Dong;Longsheng Chu;Hongliang Sun;S. Grasso;Chunfeng Hu
中科院分区：
文献类型：
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作者：
Xiaojia Su;Jian Dong;Longsheng Chu;Hongliang Sun;S. Grasso;Chunfeng Hu
MoAlB陶瓷的高温强度和高温抗氧化性是MoAlB陶瓷研究的热点。从Mo、Al和B的元素粉末开始通过反应放电等离子体烧结获得块体。在中间温度下表征化学反应以定义反应机理。结果表明，MoAl B是由Al 8 Mo 3、Mo B和B或Al 8 Mo 3、Mo和B在1000 °C反应生成的。密度为6.26g/cm 3（相对密度为97.1%，MoB杂质为2.0体积%）的致密块状MoAlB陶瓷，在真空中在1200 °C下固结10分钟。还报道了显微组织、物理和机械性能。平均晶粒尺寸为长14.5 μm，宽6.9 μm。测得的热膨胀系数和热导率分别为10.1 × 10− 6 K − 1和37.56 W·m−1·K−1，室温下的电导率为2.70 × 106 S/m。弯曲强度、断裂韧性和压缩强度分别为465.8MPa、5.45MPa·m1/2和1467.6MPa。室温下，在10-300 N范围内，随着载荷的增加，合金的维氏硬度从13.95 GPa下降到9.79 GPa。最重要的是，高温硬度可保持高达700 °C而不会发生任何降解，表现出出色的高温刚度。
The renewed research interest on MoAlB ceramic is motivated by its high temperature strength and high temperature oxidation resistance. Bulks were obtained by a reactive spark plasma sintering starting from elemental powders of Mo, Al, and B. Chemical reactions were characterized at intermediate temperatures to define reaction mechanism. The results showed that MoAlB resulted from the reaction of Al8Mo3, MoB, and B or Al8Mo3, Mo, and B at 1000 °C. A dense bulk MoAlB ceramic, with a density of 6.26 g/cm3(relative density of 97.1%, MoB impurity of 2.0 vol.%), was consolidated at 1200 °C for 10 min in vacuum. Microstructure, physical and mechanical properties were also reported. The average grain size was 14.5 μm in length and 6.9 μm in width. The measured thermal expansion coefficient and thermal conductivity were 10.1 × 10−6K−1and 37.56 W⋅m−1⋅K−1, respectively, and the electrical conductivity was determined as 2.70 × 106S/m at room temperature. The flexural strength, fracture toughness, and compressive strength were 465.8 MPa, 5.45 MPa⋅m1/2, and 1467.6 MPa, respectively. Vickers hardness decreased from 13.95 to 9.79 GPa with the increasing load in the range of 10–300 N at ambient temperature. Most significantly, the high temperature hardness could be retained up to 700 °C without any degradation, exhibiting excellent high temperature stiffness.