Spark Plasma Sintering, Phase Composition, and Properties of AlMgB14 Ceramic Materials

AlMgB14-based materials have been synthesized by spark plasma sintering of an Al12Mg17-B powder mixture at 1300 and 1400 degrees C. The phase composition, structure, and properties of these materials have been studied. According to X-ray powder diffraction evidence, spark plasma sintering leads to the formation of the AlMgB14 phase and the MgAl2O4 spinel. The content of the AlMgB14 phase in the materials is similar to 95 wt %. At a sintering temperature of 1400 degrees C, the resulting material has a hardness and relative density of 30.1 GPa and 99.3%, respectively. It has been demonstrated that a major source of oxygen in the powder mixture is a B2O3 oxide film on the boron powder surface. Thus, when the Al12Mg17 intermetallic powder is used as a precursor, the reaction of AlxMgy intermetallic compounds with B2O3 leads to the formation of the MgAl2O4 spinel.