用湿化学法制备电子材料用ZnO粉末

本文研究用湿化学法——ＮＨ＿３法改性ＺｎＯ粉末使之用于电子材料．用ｘ－ｒａｙ衍射分析和ＳＥＭ分析方法确定了焙烧温度、球磨时间等主要工艺参数；用ＳＥＭ分析、ＢＥＴ分析、粒度与粒度分布分析方法研究了改性前后ＺｎＯ粉末的赋存状态．压敏电阻验证试验结果表明，改性后的ＺｎＯ粉末可以制备出小电流性能很好的ＺｎＯ压敏电阻．     

Specific structural features of LnZrOx (Ln: La, Sm) mixed oxides prepared by different methods

LnZrOx(Ln: La, Sm) mixed oxides of Ln: Zr = 1 were prepared by different methods(complex polymerized method, sorption of cations on starch from aqueous salt solution and conventional co-precipitation with additional redispersion of precipitate by ultra sound) and calcined at 700–1300 °C. Their specific structural features and changes were studied and discussed. Various characterization methods were used such as X-ray diffraction,Electron microscopy, Fourier-transform infrared and Raman spectroscopy, UV–Vis spectroscopy, X-Ray absorption fine structure and X-ray photoelectron spectroscopy.The formation of pyrochlore structure occurred at 1100–1300 °C from fluorite-like pseudocubic phase ZrO_2 regardless the method of preparation. This phase had a block-like structure consisting of ZrO_2 nanocrystals stabilized by Ln cations and residual anions such as hydroxyls and carbonates. The desorption of such anions with heating already started at 900 °C and lead to local changes of Zr cations coordination to octahedral and to the formation of pyrochlore nanodomains inclusions within fluorite-like phase. The increased cation mobility and further elimination of anions caused by further heating was accompanied by the formation of bulk pyrochlore phase at 1100–1300 °C. Even after calcination at 1300 °C the local microheterogeneity as well as defects were identified at domains boundaries or sintered microstructure. These specific features of the formed pyrochlores depend on the method of preparation.     

化瘀止痛散的薄层鉴别研究

按照新的药品注册管理办法要求,研究了化瘀止痛散的薄层鉴别方法.通过实验考察了供试品前处理工艺、筛选薄层鉴别的色谱条件,建立了化瘀止痛散中血竭、冰片、三七的薄层色谱方法.实验结果表明:该方法简便,专属性强,重现性好,可用于化瘀止痛散的定性质量控制.     

醇盐水解法合成高纯超细BaTiO_3粉体

近年来,高纯超细BaTiO_3粉体的制备技术发展十分迅速。它们在BaTiO_3电子陶瓷的应用研究中起着日益重要的作用。尽管BaTiO_3粉体的合成方法很多,但醇盐水解法有其不可争辩的优点。本文就醇盐水解法合成BaTiO_3粉体的制备技术及其发展作综合评述。     

Mechanisms of two-stage martensitic transformation in Ti-Ni-Hf alloy powder

The Ti-Ni-Hf shape memory alloy powders were prepared by plasma rotating electrode process. And the powders were featured with the perfect sphericity and smooth surface. Moreover, the grain size was refined in the Ti-Ni-Hf alloy powders due to the rapid cooling rate during plasma rotating electrode process. It was found that the Ti-Ni-Hf alloy powders had the typical self-accommodation configuration including spear-like, mosaic-like and lath-like martensite. Various twins, such as (001) compound twin, (011) type I twin as well as {111} type I twin, were observed in Ti-Ni-Hf alloy powders. Differing from the bulk Ti-Ni-Hf alloy, two-stage transformation corresponding to B2⇌B19’ martensitic transformation was detected in the as-received Ti-Ni-Hf alloy powders. In addition, the martensitic transformation behaviors were closely related to the annealing temperatures. The Ti-Ni-Hf alloy powders with low annealing temperature of 500 ​°C still exhibited two-stage martensitic transformation, while two-stage martensitic transformation changed into single martensitic transformation in the Ti-Ni-Hf alloy powders with the higher annealing temperature of 900 ​°C. And finally the possible mechanisms for the evolution of martensitic transformation behaviors were discussed.     

牙科ZTA陶瓷复合粉体的研究进展

增韧补强是现代技术陶瓷研究的重要领域。ZTA纳米复相陶瓷借助于ZrO2的相变特性能够显著改善陶瓷的韧性。首先从断裂力学的角度分析了影响陶瓷增韧的显微结构因素，在此基础上，介绍了ZTA增韧陶瓷复合粉体的几种制备工艺，分析比较了各种工艺的特点，指出了ZTA陶瓷粉体制备的发展方向。