Cubic boron nitride(CBN) micro powders and mixture of CBN micro powders with Al or Ti powders were fast heated at 1 300,1 400,1 450,1 500℃,and then kept for 5 min under spark plasma sintering (SPS).The obtained powde...Cubic boron nitride(CBN) micro powders and mixture of CBN micro powders with Al or Ti powders were fast heated at 1 300,1 400,1 450,1 500℃,and then kept for 5 min under spark plasma sintering (SPS).The obtained powders were analyzed with XRD.The results show that,simple CBN kept cubic structure after heated at 1 300℃;when the temperature rose to 1 400℃,some CBN was transformed into hexagonal structured boron nitride(hBN).As for CBN micro powders mixed with aluminum or titanium micro powders,the onset transforming temperature of CBN to hBN get raised.This results indicated that the structural transformation of boron nitride begun from the surface of CBN crystal particle,different coexist elements affect the surface situation of CBN particles.As the stabilities of CBN crystal particle surface improved,the onset structural transform temperature of CBN was also increased.展开更多
Cubic boron nitride（c-BN） was synthesized through benzene thermal method at a lower temperature of （300℃） by selecting liquid（（C2H5）2O·）BF3 and Li3N as reactants. Hexagonal boron nitride（h-BN） and orth...Cubic boron nitride（c-BN） was synthesized through benzene thermal method at a lower temperature of （300℃） by selecting liquid（（C2H5）2O·）BF3 and Li3N as reactants. Hexagonal boron nitride（h-BN） and orthorhombic boron nitride（o-BN） were also obtained. The samples were characterized by X-ray powder diffractometry and Fourier transformation infrared spectroscopy. The results show that all the BF3, BCl3 and BBr3 in the same family compounds can react with Li3N to synthesize BN since the strongest bond of B—F can be broken. Compared with BBr3, liquid （C2H5）2O·BF3 is cheaper, less toxic and more convenient to operate. Li3N not only provides nitrogen source but also has catalytic effect on accelerating the formation of c-BN at low temperature and pressure.展开更多
基金support provided by Natural Science Foundation of Hebei Province(No.E 2006000226)
文摘Cubic boron nitride(CBN) micro powders and mixture of CBN micro powders with Al or Ti powders were fast heated at 1 300,1 400,1 450,1 500℃,and then kept for 5 min under spark plasma sintering (SPS).The obtained powders were analyzed with XRD.The results show that,simple CBN kept cubic structure after heated at 1 300℃;when the temperature rose to 1 400℃,some CBN was transformed into hexagonal structured boron nitride(hBN).As for CBN micro powders mixed with aluminum or titanium micro powders,the onset transforming temperature of CBN to hBN get raised.This results indicated that the structural transformation of boron nitride begun from the surface of CBN crystal particle,different coexist elements affect the surface situation of CBN particles.As the stabilities of CBN crystal particle surface improved,the onset structural transform temperature of CBN was also increased.
基金Projects(2027300750372006) supported by the National Natural Science Foundation of China
文摘Cubic boron nitride（c-BN） was synthesized through benzene thermal method at a lower temperature of （300℃） by selecting liquid（（C2H5）2O·）BF3 and Li3N as reactants. Hexagonal boron nitride（h-BN） and orthorhombic boron nitride（o-BN） were also obtained. The samples were characterized by X-ray powder diffractometry and Fourier transformation infrared spectroscopy. The results show that all the BF3, BCl3 and BBr3 in the same family compounds can react with Li3N to synthesize BN since the strongest bond of B—F can be broken. Compared with BBr3, liquid （C2H5）2O·BF3 is cheaper, less toxic and more convenient to operate. Li3N not only provides nitrogen source but also has catalytic effect on accelerating the formation of c-BN at low temperature and pressure.
