Synthesis of (Ca,Mg)α′-Sialon-AlN-BN powders from boron-rich blast furnace slag by microwave carbothermal reduction-nitridation

摘要

(Ca,Mg)α′-Sialon-AlN-BN powders were synthesized by carbothermal reduction and nitridation (CRN) method using boron-rich slag, one of the intermediate products from pyrometallurgy separation of pageit, as the staring material. The influences of synthesis temperature and holding time on phase composition and microstructure during a microwave CRN were studied by XRD, SEM and EDS. The comparison between two heating techniques, conventional and microwave heating, to the synthesized powder was presented as well. The experimental results revealed that the phase compositions and microstructures of the synthesized products were greatly affected by synthesis temperature and holding time. With an increase in the synthesis temperature and holding time, the relative amount of α′-Sialon increased and became the main crystalline phase at 1400 amount of β-SiC. Elongated α′-Sialon grains, short rod AlN grains, aggregate nanoscale BN grains were observed in synthesized powders. The reaction temperature of microwave heating method was reduced by 80 was shortened by 2h, and more elongated α′-Sialon grains with large aspect ratio were observed.