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

AlMgB 14 -based materials have been synthesized by spark plasma sintering of an Al 12 Mg 17 –B powder mixture at 1300 and 1400°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 AlMgB 14 phase and the MgAl 2 O 4 spinel. The content of the AlMgB 14 phase in the materials is ~95 wt %. At a sintering temperature of 1400°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 B 2 O 3 oxide film on the boron powder surface. Thus, when the Al 12 Mg 17 intermetallic powder is used as a precursor, the reaction of Al x Mg y intermetallic compounds with B 2 O 3 leads to the formation of the MgAl 2 O 4 spinel.