关键词: 碳化硼, 聚乙烯醇, 溶胶-凝胶法

Abstract: Polyvinyl borate gel was prepared with polyvinyl alcohol (PVA) and boron acid as raw materials,which was employed as precursor for preparing boron carbide and then it was pyrolyzed and reduced to form boron carbide powder by carbonthermal process.Effects of amount-of-substance ratio of polyvinyl alcohol to boron acid,pyrolyzed temperature of the precursor, carbonthermal reduction temperature,and reduction time of pyrolyzed precursor on boron carbide synthesis were respectively investigated.Intermediate and product were respectively characterized by FT-IR,chemical composition,XRD,SEM,and particle size analysis etc..Results indicated that the optimum raw material mix ratio for precursor polyvinyl borate was n(PVA)∶n(boron acid)=4∶1；B₄C powder with a primary particle size of 10 μm could be obtained when the precursor was pyrolyzed at 600 ℃ for 2 h,and then treated at 1 300 ℃ for 2 h.

Key words: boron carbide, polyvinyl alcohol, sol-gel method