Effect of two-step heat treatment on the phase formation of MgAlB14

Functional ceramics MgAlB14 disks were prepared by a two-step heat treatment. In the first step, Mg6AlB14 disks were fabricated through composition of uniformly mixed Mg, Al, and B powders in the form of pressed disks heated at 850°C in closed argon atmosphere. And in the second step, target MgAlB14 disks were obtained by decomposition of the Mg6AlB14 disks sintered in vacuum. It has been found that the main peaks of MgAlB14 were sharp except the common impurity-MgAl2O4 according to X-ray diffractions (XRD). The nano-hardness of the sample was about 11GPa. And the heat treatment effects in the second step on the phase formation of MgAlB14 were also studied.