合成原料中Mg配比对燃烧合成制备的ZrB_2粉体粒度与纯度的影响研究  

Study of the influence of different stoichometry of Mg in starting mixture on particle size and purity of ZrB_2 powder prepared by combustion synthesis

作　　者：喇培清[1] 韩少博[1] 卢学峰[1] 鞠倩[1] 魏玉鹏[1] 

机构地区：[1]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,兰州730050

出　　处：《粉末冶金技术》2013年第1期3-8,13,共7页Powder Metallurgy Technology

基　　金：国家自然科学基金资助项目(51164022)

摘　　要：利用燃烧合成法制备了ZrB2粉体,研究了不同Mg含量对燃烧合成制备的ZrB2粉体粒度和纯度的影响。结果表明,Mg过量5%合成的ZrB2粒径最小,纯度最高。Mg含量对ZrB2粉体粒度的影响机理为:Mg过量一定程度,会降低反应绝热温度,使产物处于高温状态的时间缩短,减小颗粒长大趋势而使得颗粒尺寸变小;当Mg含量进一步提高,其与ZrO2反应加强,生成更多的中间产物Zr,使得直接合成ZrB2的反应加强而促进颗粒生长。Mg含量对ZrB2粉体纯度的影响机理为:Mg过量一定程度,弥补了燃烧合成过程中的挥发损失,提高了还原转化率,使粉体纯度提高;当Mg含量进一步提高时,其挥发消耗更多反应热,使得燃烧温度降低,反应为固态反应,转化率降低而残余更多ZrO2;过多的MgO和剩余的B2O3反应生成酸不溶杂质,使粉末纯度降低。ZrB2 powder was prepared by combustion synthesis. The influence of different amounts of Mg on particle size and purity of ZrB2 powders synthesized by combustion synthesis was studied. The results show that ZrB2 powder made by reactant mixture with 5% excess amount of Mg has the finest particles and highest purity. The mechanism of the influence on particle size is that a considerate amount of Mg lowers the adiabatic temperature and shortens the duration of product at elevated temperature, resulting in a decrease of particle coarsening, and thus fine particles are obtained; while excessive amount of Mg enhances the reaction of Mg and ZrO2 , producing more intermediate product of Zr, thus the reaction directly producing ZrB2 is promoted, coarsening the particles. The mechanism of the influence on purity of product is that to some extent, excess amount of Mg compensate its loss due to volatilization at high temperature, improving the conversion of the reaction and thus increasing purity of final product. While excessive amount of Mg consumes more heat due to its volatilization, thus the combustion temperature is decreased and the solid-state reaction proceeds predominantly, so more ZrO2 is remained ; In addition, excessive amount of Mg increases the possibility of the formation of impurities not soluble in acid by the reaction of MgO and the remaining B2O3 , lowering the purity of the product,

关 键 词：ZrB2粉体 燃烧合成 Mg添加量 粒径 纯度 

分 类 号：TQ630.1[化学工程—精细化工]