Study on Preparation of High α-Phase Silicon Nitride Ceramics by Efficient Nitridation of Bulk Silicon
High α-phase silicon nitride bulk was prepared by direct nitridation method combined with high-energy ball milling.Taking silicon powder and α-Si3N4 diluents with different mass ratios as the raw material,the green block with different thicknesses were compressed,then the Si3N4 bulk materials were prepared by nitriding at 1350℃for different times.The process factors for the synthesis of silicon nitride bulk materials through direct nitridation reaction of silicon blocks were investigated.The results show that when the silicon block with a thickness of 3 mm and 15%diluent(α-Si3N4)content is nitrided at 1350℃for 3 h under a flowing nitrogen gas atmosphere,the nitridation effect is the best,and the products consist of three phases.The mass content of each phase is as follows:α-Si3N4(88.7%),β-Si3N4(10.2%),and Si(1.1%).The process successfully synthesizes silicon nitride bulk materials with a high α-phase content.The results of the study provide evidence for the efficient preparation of bulk silicon nitride with high α-phase content.
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