温度与原料组成对硼/碳热还原法制备高纯ZrB_2粉体的影响  

Effects of temperature and raw materials composition on high-purity ZrB_2 powders prepared by boro/carbothermal reduction

作　　者：冯慧丽[1] 黄启忠[1] 苏哲安[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2017年第2期212-220,共9页Materials Science and Engineering of Powder Metallurgy

基　　金：国家重点基础研究发展规划(973计划)资助项目(2011CB605801)

摘　　要：以ZrO_2、硼源(B_4C和B_2O_3)、碳源(石墨粉和炭黑)为原料,分别采用ZrO_2-B_4C-C体系和ZrO_2-B_4C-B_2O_3-C体系,在氩气气氛下通过硼/碳热还原反应合成ZrB_2粉体,研究合成温度、碳源、硼源以及原料配比对ZrB_2粉体纯度、形貌及粒度的影响。结果表明:随反应温度升高,ZrB_2粉体的纯度提高;以石墨粉为碳源时,适当增加过量的B_4C也可提高ZrB_2粉体的纯度;由B_4C和B_2O_3同时充当硼源时,需加入更多过量的B才能获得高纯度的ZrB_2;与采用石墨粉做碳源相比,用炭黑做碳源可在较低温度下合成ZrB_2粉体,并且不需加入过量的B。以ZrO_2,B_4C和炭黑为原料,按照n(ZrO_2):n(B_4C)=2:1配比,在1 350℃保温1.5 h,得到纯度高于99%的柱状ZrB_2粉体,宏观平均粒径D50为12.67μm。ZrB2 powders were synthesized using ZrO2, two kinds of boron sources （B℃ and B203） and two kinds of carbon sources （graphite and carbon black） as raw materials in argon atmosphere with the reaction system of ZrO2-B4C-C and ZrOz-B4C-B203-C. The effects of heating temperature, carbon source, boron source and reaction system on the purity, morphologies and powder size of ZrB2 powders were studied. The results show that the purity of ZrB2 powders can be improved by elevating the reaction temperature. Adding the appropriate amount of excessive BaC can also enhance the purity when the graphite is used as carbon source. More excessive B should be added when using both B4C and B203 as boron source. Compared with graphite, the carbon black can be used to synthesize ZrB2 powders with lower temperature and no excess B. When the mole ratio of ZrO2/BaC is 2, the columnar ZrB2with purity over 99% can be synthesized at 1 350 ℃ for 1.5h in argon atmosphere using ZrO2 , B4C and carbon black as raw materials, the macroscopical average grain size of ZrB2 powders is 12.67 μm.

关 键 词：硼化锆 硼/碳热还原 高纯 碳源 合成工艺 

分 类 号：TQ174.758[化学工程—陶瓷工业]