Sn-Doped Mn3GaN Negative Thermal Expansion Material for Space Applications

摘要:

采用球磨后放电等离子体烧结的方法制了化学成分为Mn3Ga1-xSnxN (x=0, 0.1, 0.2, 0.3, 0.4) 的反钙钛矿锰氮化合物。研究了其热膨胀性能、导热性能和力学性能。结果表明：所有样品热膨胀性能与Sn含量有关，随着Sn含量的增加，负热膨胀温区向高温移动。其中，Mn3Ga0.9Sn0.1N化合物在279到338 K温区内的负热膨胀系数为–27.5×10-6 K-1，负热膨胀温区宽度为59 K。而Mn3Ga0.6Sn0.4N在363~400 K温区内的热膨胀系数较小，接近零膨胀。此外，这类负热膨胀材料的热导率约为3.2 W·(m·K)-1，压缩强度约为210 MPa。

Abstract:

The anti-perovskite manganese nitrides with the general formula Mn3Ga1-xSnxN (x=0, 0.1, 0.2, 0.3, 0.4) were fabricated by mechanical ball milling followed by spark plasma sintering (SPS). The temperature dependence of thermal expansion, thermal conductivity and mechanical properties were investigated. The results show that the negative thermal expansion (NTE) operation-temperature window shifts toward higher temperature with increasing of Sn concentration. Typically, the linear NTE coefficient of the Mn3Ga0.9Sn0.1N compound reaches as much as –27.5×10-6 K-1, with an operation-temperature window of 59 K from 279 to 338 K. In addition, the coefficient of thermal expansion (CTE) of Mn3Ga0.6Sn0.4N is very low in the temperature range of 363~400 K. The value of thermal conductivity of this material is about 3.2 W·(m·K)-1 around room temperature. Compression test indicates that the compressive strength is about 210 MPa. This NTE material may possibly be exploited to design the critical components for space applications.