摘要
采用TEM技术对Al2O3基陶瓷复合材料中LiTaO3颗粒内的电畴结构进行了研究。结果表明:LiTaO3单晶中不可能形成的90°畴出现在LiTaO3/Al2O3(简称LTA)陶瓷复合材料中的LiTaO3晶粒内,且以其为主,这对于六方结构的LiaO3来说,是一个新的发现。采用不同烧结方法制备的LTA陶瓷复合材料中LiTaO3晶粒内的电畴结构有很大差别。1500℃热压烧结,LTA陶瓷复合材料中LiTaO3晶粒内的电畴结构主要为高密度的薄片状90°畴以及箭尾型90°畴;200 MPa冷等静压成型后经1300℃无压烧结,LTA中LiTaO3晶粒内除了薄片状与箭尾型的90°畴结构外,还形成了尖劈状与板条状的90°畴结构;1 300℃热压烧结,LTA中LiTaO3晶粒内的电畴结构大多为板条状的90°畴,另外还有少量尖劈状的90°畴。LiTaO3晶粒内部电畴结构的不同与LiTaO3晶粒受周围Al2O3基体晶粒的应力作用、LiTaO3的化学组成配比以及薄膜试样制备过程中的机械研磨抛光有关。
The domain structures in LiTaO3 particles dispersed in the Al2O3 matrix ceramic composite were investigated systematically using the TEM technique. The results show that 90°C domain structures mainly occur in LiTaO3 grains in LiTaO3/Al2O3 (denoted by LTA) ceramic composite, which is impossible in the LiTaO3 single crystal. This is a new discovery for hexagonal LiTaO3. Domain structures in LiTaO3 grains very greatly in LTA ceramic composites fabricated by different sintering methods. The influencing factors of domain structures are also discussed. Domain structures in LiTaO3 grains in LTA fabricated by hot-pressing at 1500°C are mainly lamellar 90°C domains of high density and herring-bone 90°C domains. Besides lamellar and herring-bone 90°C domains, wedge shaped and band shaped 90°C domains are also found in LiTaO3 grains in LTA prepared by cold isostatic pressing under a pressure of 200 MPa followed by pressureless sintering at 1300°C. Most band shaped 90°C domains and a few of wedge shaped 90°C domains are observed in LTA hot-pressed at 1300°C. The differences of domain structures in LiTaO3 grains are related with the stress round LiTaO3 grains acted by Al2O3 grains, the chemical composition of LiTaO3 and the mechanical grinding and polishing in the process of fabricating specimens.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2003年第12期1135-1139,共5页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金(59972006)资助项目
关键词
钽酸锂
氧化铝
电畴结构
陶瓷复合材料
透射电子显微镜
Alumina
Grain size and shape
Grinding (machining)
Hot pressing
Particles (particulate matter)
Polishing
Single crystals
Sintering
Transmission electron microscopy
