ZrW_(2-x)Mo_xO_8晶体结构及热膨胀性能  

Crystallization behavior,crystal structure and thermal expansion property of ZrW_(2-x)Mo_xO_8

作　　者：刘芹芹[1] 程晓农[1] 杨娟[1] 孙秀娟[1] 臧传亮[1] 

机构地区：[1]江苏大学材料科学与工程学院,江苏镇江212013

出　　处：《江苏大学学报（自然科学版）》2011年第3期305-309,共5页Journal of Jiangsu University：Natural Science Edition

基　　金：国家自然科学基金资助项目(50772044);国家博士后基金资助项目(200802990001);江苏省自然科学基金资助项目(BK2008224);江苏省高校自然科学重大基础研究项目(09KJA430001)

摘　　要：采用共沉淀法,以硝酸氧锆、钨酸铵和钼酸铵为原料制备了纯度较高的ZrW2-xMoxO8粉体,分别采用热重-差热和X射线衍射分析了W/Mo摩尔比对ZrW2-xMoxO8的结晶行为、晶体结构以及热膨胀性能的影响.结果表明:Mo的掺杂不会影响其热膨胀性能,所得ZrW2-xMoxO8均具有良好的负热膨胀特性,而ZrW2-xMoxO8的室温晶胞参数和合成温度均随着Mo取代量的增加而降低.x<0.5时,ZrW2-xMoxO8室温晶体结构为α-ZrW2O8相,ZrW2O8由氧化物原料在高温反应生成.高温XRD结果表明:ZrW2O8和ZrW1.5Mo0.5O8在高温会发生α-β相变,负热膨胀系数随之发生明显变化;当x≥0.5时,ZrW2-xMoxO8则由其对应的三方相或单斜相在高温转变而成,如果其室温相为β相,则在高温转变为不具负热膨胀特性的三方相.ZrW2-xMoxO8 powders were synthesized by coprecipitation method using zirconium oxynitrate, ammonium tungstate and ammonium molybdate as raw materials. The effects of W/Mo ratio on the crystallization behavior, crystal structure and thermal expansion property of ZrW2-xMoxO8were studied by differential scanning calorimetry （TG -DSC ） anti Powder X-ray diffraction （XRD）. The results show that Mo substitution does not influence the negative thermal expansion property of the resulted ZrW2-xMoxO8 which was synthesized either via the reaction of oxides raw materials （x 〈 0. 5 ） at transition of its corresponding trigonal and monoclinic phase （x x≥0.5）. The lattice constant at room temperature and the synthesis temperature decrease with the decreasing of W/Mo ratio. At high temperature, ZrW2-xMoxO8 adopting α-βZrW2-xMoxO8structure transforms to trigonal phase which does not possess NTE property.

关 键 词：ZrW2-xMoxO8 结晶行为 晶体结构 热膨胀性能 相变 

分 类 号：TB332[一般工业技术—材料科学与工程]