Effects of aluminum on micro-sized pore structure of porous MoAlB ceramics fabricated via reactive synthesis

Abstract

By using mixtures of Mo, Al and B powders with a molar ratio of 1/n/1 (n, 1.4–1.9 in 0.1 increments), porous MoAlB ceramic was successfully synthesized thorough activation reaction technology. The effects of aluminum content on phase transformation, volume expansion, microstructure and pore structure parameters (including pore size, porosity and permeability) were investigated systematically. With an increasement of Al content from 1.4 to 1.9, the open porosity reveals a trend of slowly increasing first and then the increment of growth rate. Meanwhile, the volume expansion, pore size and permeability show a similar trend with the open porosity. The reasons for these pore structure parameters alteration evolution are thoroughly explored. The pore forming mechanism is also investigated.