摘要
通过熔融法制备出以钙长石为主晶相的CaO-Al2O3-SiO2(CAS)系微晶玻璃,采用差热分析、X射线衍射和扫描电子显微镜等测试手段,对不同TiO2添加量的CAS系微晶玻璃的结构和形貌进行表征,同时采用顺磁共振和正电子湮没寿命谱技术,探讨不同TiO2添加量对微晶玻璃微观结构与力学性能关系的影响.结果表明:不同TiO2加入量并不影响CAS系微晶玻璃析出的主晶相类型,但会使体系的析晶峰温度降低,促进体系析晶;在微晶玻璃高温熔融及热处理时,Ti4+会被还原成Ti3+,同时产生氧空位,Ti3+—O—Ti3+与氧空位缺陷间自旋角关联作用的强弱,直接影响抗弯强度的大小;间隙Ti4+的形成,造成缺陷和Al、Si空位的存在,使材料的物理化学性能发生改变.间隙Ti4+虽然造成缺陷和空位的存在,但Ti4+与O2-间通过静电作用,使原来相互独立的氧离子成为一体,键强增大,导致抗弯强度增大;当TiO2超过6%时,部分Ti4+取代Si4+,而Ti—O键比Si—O键键强小,导致抗弯强度减弱.在核化温度为750℃,核化时间为2h,晶化温度为950℃,晶化时间为2h,TiO2质量分数为6%时,CAS系微晶玻璃具有优良的力学性能,抗弯强度为314MPa,显微硬度为830MPa.
CaO-Al2O3-SiO2 system （CAS） glass-ceramics with anorthite crystal structure was prepared by melt-method. Its microstructure and morphology were characterized by differential thermal analysis （ DTA）, X-ray dif-fraction （XRD） and scanning electron microscope （SEM）. The effects of TiO2 content on the relationship be-tween microstructure and mechanical properties for the CAS glass-ceramics were also investigated by electron para-magnetic resonance （EPR） and the position annihilation technique （PAT）. The results showed that the TiO2 content does not affect the type of the main crystalline phase of CAS glass-ceramics, but it could reduce the crys-tallization peak temperature and promote the crystallization. The relationship between g factor and bending strength showed that during the melting and heat-treatment process, part of the Ti^4- ions were reduced to Ti^3＋ and formed oxygen vacancies, the spin angular correlation between Ti^3＋ -O-Ti^3＋ and oxygen vacancies affected the bending strength directly. The relationship between positron lifetime and bending strength showed that interval Ti^4＋ could make some defects and Al, Si vacancies, which could affect the mechanical properties. Electrostatic interaction between Ti^4＋ and 0^2- could make the independent oxonium ion into an integral, which was favourable to bending strength. When the TiO2 content was higher than 6% , some Si^4＋ were substituted by Ti^4＋ , and the Ti-O bond was weaker than the Si-O bond, which led to a decrease in bending strength. When the content was 6% , the mierohardness was 830 MPa,and the bending strength was 314 MPa in the heat treatment conditions of nucleation temperature 750 ℃, nucleation time 2 h, crystallization temperature 950 ℃, crystallization time 2 h.
出处
《深圳大学学报（理工版）》
EI
CAS
北大核心
2013年第3期319-324,共6页
Journal of Shenzhen University(Science and Engineering)
基金
国家自然科学基金资助项目(50974090)
深圳市科技研发资金资助项目(JC201105130413A)~~
关键词
微晶玻璃
顺磁共振
正电子湮没
力学性能
微观结构
显微硬度
glass ceramics
electron paramagnetic resonance
position annihilation technique
mechanicalproperties
microstructure
microhardness
