Low-temperature Synthesis Of Precursor Cracking Route For Boron Carbide

The apply area of Boron carbide is broadening gradually since its supernormal hardness,low density,strong neutron absorb ability.On industry,preparation methods of boron carbide are carbothermic reduction and magnesium reduction primarily.There are some problems such as high preparation temperature(above 2000℃generally),high energy consumption,low produce efficiency,serious environment pollute in production process.How to get synthesis temperature and energy consumption down becomes the hotspot of the area of boron carbide synthesis and preparation.Boron carbide powder is prepared by precursor cracking method at low temperature in this paper.Polymer precursor is prepared to B4C powder by esterification with polyving akohol,glucose,solubility starch,sucrose as carbide source and boric acid as boron source and cracked and sintered in vacuum.FTIR spectrum of polymer precursor shows that the bonding of B-O-C is supported by the absorption peak at 1050cm-1 and proves that the esterification reaction occurs between carbide source and boric acid.The component of precursor cracking production is C and B2O3 by XPS,XRD,SEM and chemistry analysis,and B2O3 exists in the pore of C matrix.And then the best preparation craft of precursor cracking production is determined by orthogonal experimental method with precursor cracking production output and mole ratio of C and B2O3 as measure standard.The lowest sintereing temperature of B4C powder is determined by thermodynamics compute.The preparation carft of process of cracking production sintered to B4C powder is determined by the analysis of sintereing temperature and sintereing atmosphere. XRD,XPS,chemistry analysis,SEM,granularity analysis of sintering production shows that boron carbide which particle diameter is small and has much free carbide and purity is low can be prepared with polyving akohol as carbide source at 1300℃;and which particle diameter is big and has few free carbide and purity is high can be prepared with glucose,solubility starch,sucrose as carbide source at 1600℃at least.Purity difference of boron carbide powder prepared with different carbide source is little(less than 1.5%),and the sintering temperature with polyving akohol as carbide source is low,and the particle diamete of powder is small,so purity and particle diamete of boron carbide powder and preparation with low cost are considered,and the best carbide source is determined polyving akohol.