三元硼化物AlMgB14超硬材料的研究进展

Research Progress of AlMgB14 Super-hard Materials

摘要:

AlMgB14超硬材料具有高硬度、低密度、低摩擦系数、高热稳定性和良好的热电性能，可以应用于耐磨、切削装备、微器件和微电子机械装置的保护涂层等领域。我们介绍了目前制备AlMgB14超硬材料的几种方法，详细介绍了我们通过分步反应法在常压条件下合成AlMgB14超硬材料。首先，在手套箱中按一定比例均匀混合Mg粉，Al粉，B粉和不同含量的Ti粉，在850 ℃密闭氩气条件下烧结2小时，得到Al和Ti掺杂的MgB2块体；第二步在真空条件下1050 ℃下烧结半小时得到目标产物AlMgB14-TiB2。对烧结后的样品进行了微观结构、超导电性和相组成等分析检测，结果显示AlMgB14晶粒细小，在晶界处有均匀细小的TiB2颗粒弥散分布。介绍了AlMgB14块体和薄膜的研究现状，论述了AlMgB14超硬材料未来的研究重点。

Abstract:

AlMgB14 is of great interest due to its extreme hardness, low density, high thermal stability and desirable thermoelectric properties. AlMgB14 is a very promising candidate as wear-resistant, self-lubricating and protective coatings for cutting tools and protective coatings for micro devices and micro electromechanical components. Some methods for preparing AlMgB14 super-hard materials were introduced, especially a two-step heat treatment method. AlMgB14 disks were synthesized at ambient pressure through a two-step heat treatment. In the first step, MgB2 disks doped with Al and Ti were fabricated through composition of uniformly mixed Mg, B, Al powders and different contents Ti powder in the form of pressed disks heated at 850 ℃ for 2 hours in closed argon atmosphere. And in the second step, target AlMgB14-TiB2 disks were obtained after sintering the MgB2 disks at 1050 ℃ for 0.5 hours in vacuum. The phase, microstructure and superconductivity were characterized by means of X-ray diffraction (XRD), Scanning electron microscope (SEM) and superconducting quantum interference device (SQUID). The grain size of AlMgB14 is fine and the nano-scale TiB2 particles as the second phase induced by Ti doping are uniformly distributed in the sample matrix. The research status on bulk and film of AlMgB14 and the future researching scope of AlMgB14 were introduced.