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Particle Size Distribution, Powder Agglomerates and Their Effects on Sinterability of Ultrafine Alumina Powders
Particle Size Distribution,Powder Agglomerates and Their Effects on Sinterability of Ultrafine Alumina Powders

Renjie ZENG,BRand,

材料科学技术学报 , 2000,
Abstract: An intensive study of the particle size distribution of four commercial ultrafine alumina powders to obtain information about the powder agglomeration and relate them to the compactibility and the sinterability has been made.
Electron Microscopy Studies on Ultrafine Zirconia Powders from Solvent Extraction with Tributyl Phosphate in Kerosene
Chuanfang YANG,Jiayong CHEN,

材料科学技术学报 , 1995,
Abstract: Solvent extraction of Zr(IV) with TBP in kerosene was used to precipitate precursory zirconia which was then processed to produce ultrafine zirconia powders. The powder prepared was examined and characterized with transmission electron microscopy (TEM) and X-ray diffraction (XRD). Effects of the conditions of preparation on powder properties were especially investigated.It was found the preclpitate was gel-like material with heterogeneous porosity. The gel transformed to polycrystalline particles when calcined to ultrafine powder at 600℃. The composition of the loaded organic phase and the conditions of washing the precipitate are two main factors affecting the properties of powder obtained
Preparation of Ultrafine Si Powders from SiH_4 by Laser-induced Gas Phase Reaction
Yali LI,Yong LIANG,Kesheng XIAO,Fen ZHENG,Zhuangqi HU,

材料科学技术学报 , 1995,
Abstract: High quality ultrafine Si powders have been synthesized from SiH4 by laser induced gas phase reaction. The powders prduced under different synthesis conditions have mean particle size of 10-120nm in diam. with narrow particle size distribution, and free of hard agglomerates.The powders are polycrystalline with the ratio of mean grain to particle diameter being between 0.3-0.7. The size of the powder increases with increasing laser power and reaction pressure,but decreases with increasing silane gas flow rate and the addition of Ar diluent. Grain sizes drop distinctly with the rise of the addition of Ar gas and laser power, but change little with the gas flow rate and reaction temperature. The formation of Si particles under different synthesis conditions is discussed
Characterization of ZnO Based Varistor Derived from Nano ZnO Powders and Ultrafine Dopants
Weizhong YANG,Dali ZHOU,Guangfu YIN,Runsheng WANG,Yun ZHANG,
Weizhong YANG
,Dali ZHOU,Guangfu YIN,Runsheng WANG and Yun ZHANG College of Material Science and Engineering,Sichuan University,Chengdu,China

材料科学技术学报 , 2005,
Abstract: Nanosized ZnO powders were prepared with a two-step precipitation method. The average size of ZnO particles was about 80 nm and their size distribution was narrow. Combining with ultrafine additive powders, ZnO base varistor was produced via an oxide mixing route. ZnO varistor derived from normal reagent grade starting materials was investigated for comparison purpose. Outstanding microstructure of the ZnO varistor derived from nanosize ZnO powders and ultrafine dopants was obtained: uniform distribution of fine ZnO grains (less than 3 microns), grain boundary and the dopant position. Higher varistor voltage (U=492 V/mm) and nonlinear coefficient (α=56.2) as well as lower leakage current (IL=1.5μA) were achieved. The better electrical properties were attributed to the uniform microstructure, which in turn led to stable and uniform potential barriers. Also this improved technique is more feasible for producing ZnO nanopowders and resulting varistor in large scales.
引黄入冀补淀工程沉沙池设计优化研究  [PDF]
人民黄河 , 2014,
Abstract: ?黄河是一条多泥沙河流,引水必然引沙,在引黄工程渠首修建沉沙池,使泥沙在特定区域集中沉积处理,将泥沙造成的环境问题限制在较小的范围内,保证总干渠清水下泄,是引黄工程成败的关键。采用准静水沉降法的原理,对选定的2条条渠梭型沉沙池方案进行了分析计算。鉴于沉沙池所占的土地均为农田,为节省土地和投资,选择沉沙池条渠底宽450m方案。按照计算,沉沙池每年淤沙量233万m3,需处理的泥沙量较大,泥沙处理问题将成为引黄入冀补淀工程最大的环境制约因素。经多方面调研,近期泥沙处理初拟方案为:优先选择低洼和闲置土地堆放,并进行平整,覆盖原状土,做好水利配套设施;黄河泥沙作为土源可以成为工程用土。

YU Ke,ZHENG Zhongshan,

材料研究学报 , 1997,
Abstract: Agglomerate structures of various ultrafine powders are studied through small-angle laser and X-ray scattering experiment. It has been found that fractal form is the general character of powder agglomerate, and fractal dimension characterization on agglomerate structure has been proposed. The relations among fractal dimension, agglomeration state and powder technological properties were discussed.

TIAN Yanwen,SHAO Zhongcai,ZHAI Yuchun,LI Baoshan,

腐蚀科学与防护技术 , 1998,
Abstract: Ni coated ZrO 2 composite powders were prepared by the electroless plating method with different Ni contents in the solution, while t ZrO 2 (10% MgO, in mole) ultrafine powders were used as raw materials. The rate of nickel deposit was easily controlled through suitable stabilizing agent and coplex agent introduced in the bath. The powders were studied by XRD, SEM, EDAX, and so on. The results show that Ni can be coated on the surface of ZrO 2 powders. Thus evenly mixing Ni with ZrO 2 could be reached .

TANG Yuhua LI Fushen,LIU Qingguo,

材料研究学报 , 1994,
Abstract: 12mol% Y2O3-ZrO2 ultrafine powders were preparated by co-precipitating method in this paper. It was investigated that the particle size, linear shrinkage and property of heat conduction of the powders were affected by calcined temperature. Wherein the oth
Study on the Preparation of Stabilized Ultrafine Zirconia Powders by Using Reverse Micellae

YANG Chuanfang,CHEN Jiayong,

无机材料学报 , 1997,
Abstract: The solubilization behavior of metal ions and ammonia solution in AOT-isooctane-water re verse micelles was investigated by injection method, the size of reverse micelles was then then determined with dynamic light scattering technique, and the microstructure of reverse micelles containing metal ions was characterized by using freeze fracture electron microscopic technique. With these micellar solutions, Y_2O_3 and CeO_2 stabilized ultrafine zirconia powders were prepared accordingly. Dif ferent kinds of preparative manners were tried to examine their effects on the quality of powders thereby derived. It was found that the swollen of metal ions in reverse micelles was an essential condition for obtaining a powder with good quality.
Tribological Properties of Heat Treated Serpentine Ultrafine Powders as Lubricant Additives

YU He-long,XU Yi,SHI Pei-jing,WANG Hong-mei,WEI Min,XU Bin-shi,

摩擦学学报 , 2011,
Abstract: The effect of heat treatment on the tribological properties of serpentine ultrafine powders(UFPs) as liquid paraffin(LP) additives were studied.The contact resistance between the tribopairs was measured during sliding to monitor the formation of tribofilm.The morphologies of the worn surfaces and the elements distribution thereon were analyzed by Scanning Electronic Microscope(SEM) and Energy Dispersive X-ray Spectroscopy(EDS),respectively.Results showed that a tribofilm of oxide layer,in which alumina and ...
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