ZrO_2对低温烧结BaO-Al_2O_3-SiO_2系微晶玻璃析晶和晶型转变的影响  

Effect of ZrO_2 on Crystallization and Phase Transformation in Low-temperature Processed BaO-Al_2O_3-SiO_2 Glass-ceramics

作　　者：芦玉峰[1] 堵永国[1] 肖加余[1] 张为军[1] 吴剑锋[1] 杨光[1] 王跃然[1] 

机构地区：[1]国防科技大学航天与材料工程学院,长沙410073

出　　处：《无机材料学报》2008年第1期159-164,共6页Journal of Inorganic Materials

基　　金：国家"863"计划(2004AA32G090)

摘　　要：用烧结法制备了化学计量比和高Ba含量的两组BaO-Al_2O_3-SiO_2(BAS)系微晶玻璃,采用差示扫描量热法(DSC)和X射线衍射分析(XRD)等手段研究了ZrO_2对BAS系微晶玻璃中六方钡长石析晶和六方钡长石向单斜钡长石晶型转变的影响.研究表明,两组BAS系玻璃的烧结温度低于850℃,晶化温度低于900℃.六方钡长石的析出为整体析晶.不加形核剂晶型转变为整体析晶;添加ZrO_2晶型转变为表面析晶.提高Ba含量或添加ZrO_2促进六方钡长石的析出和晶粒细化.化学计量比的BAS系微晶玻璃中添加ZrO_2明显促进晶型转变.高Ba含量的BAS系微晶玻璃中添加ZrO_2表现为抑制晶型转变,850℃保温100h不发生转变.BaO-Al2O3-SiO2（BAS） glass-ceramics with stoichiometric and off-stoichiometric celsian composition were fabricated, doped with B2O3 for melting and sintering. Crystallization and phase transformation characters of two groups of BAS glass-ceramics with and without ZrO2 were investi- gated by differential scanning calorimetry （DSC）, X-ray diffraction （XRD） and dilatometry. Results show that for both BAS glasses, the sintering temperature is lower than 850℃ and crystallization peak temperature is lower than 900℃. The crystallization characteristic of hexacelsian in each sample is bulk nucleation and three-dimensional growth because Avrami exponent is 2.8-3.9. The crystallization characteristic of monocelsian in the sample doped with ZrO2 is surface nucleation and one-dimensional growth because Avrami exponent is 0.95, while it is bulk nucleation and three-dimensional growth because Avrami exponent is about 3.0 in the sample without nucleation agent. It reveals that crystallization peak temperature and activation energy get lower in stoichiometric BAS glass-ceramics doped with ZrO2, while the crystallization peak temperature get higher in off-stoichiometric BAS glass-ceramics doped with ZrO2. Stoichiometric BAS glass-ceramics doped with ZrO2 crystallized at 850℃ for 12h is completely transformed into monocelsian. Monocelsian will not be detected in off-stoichiometric BAS doped with ZrO2 crystallized at 850℃ for 100h.

关 键 词：微晶玻璃 钡长石 低温烧结 析晶 晶型转变 

分 类 号：TG171[金属学及工艺—金属表面处理]