The Process of Preparing AlMgB14 by Field-Activated and Pressure-Assisted Synthesis

The aim of this paper was to find a new way to synthesize the hard, super-abrasive ceramic AlMgB14 from elements. The reactive sintering was by the field-activated and pressure-assisted synthesis (FAPAS) method performed at 1400°C for 7 min under a pressure of 60 MPa. The various samples produced were observed and determined by the scanning electron microscopy (SEM), the energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and the transmission electron microscopy (TEM). The results showed that the products contained AlMgB14 with a few Al2MgO4. These samples had a highest hardness of 28.9 GPa. The average density of the samples was 2.62 g/cm3, and the fracture toughness was 3.21 MPa·m0.5. Annealing boron powder in vacuum was an effective way to reduce the oxygen contamination. When Al2O3 tube was used to isolate the powders from die, the concentrated AlMgB14 was obtained at a lower temperature in a shorter time, for the electric current could flow through the powders entirely.