还原反应制备硼化铪粉体的研究

Investigation on Synthesis of Hafnium Diboride Powder by Reductive Reaction

在真空条件下,通过氧化铪和碳化硼反应制备出高纯硼化铪粉体并采用X射线衍射及扫描电子显微镜对其物相组成和形貌进行表征。结果表明:在真空条件下,氧化铪和碳化硼在1300℃的温度下即可发生反应,与由吉布斯自由能和范特霍夫等温公式所得结果相吻合。硼化铪晶粒尺寸随着烧结温度和保温时间的增加而增大,保温时间对其影响更明显。过量的碳化硼对硼化铪的结晶性有帮助,并且硼化铪的结晶度随着碳化硼的增加得到提高。

High pure hafnium diboride （HfB2 ） powders have been successfully prepared by the reaction of hafnium dioxide （HfO2 ） and boron carbide （B4C） in vacuum. The structure and morphology were characterized by X-ray diffraction （XRD） and scanning electron microscope （SEM）. It shows that FIfO2 and B4C can react with each other at 1300 ℃, and this is in agreement with the result deduced from Gibbs free energy changes （AGRT） and Van Hough isothermal formula. The grain sizes of the synthesized nfn2 increase with heat-treatment temperature and holding time, and the holding time have a greater influence on particle size. The crystallization of HfB2 powder were promoted by the excess of B4 C and the crystallization level of HfB2 improved with B4C content increase.