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ANIONIC SPECIES OF SiO_2-CONTAINING SODIUM ALUMINATE SOLUTIONS

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Acta Metallurgica Sinica(English Letters) 1990年第12期3卷 431-434页

作者： liu Miaoxiu ZHOU Peifang CHEN Nianyi Shanghai Institute of metallurgy,Academia Sinica,Shanghai,chinaLI Yu Shanghai university of science and technology,Shanghai,chinaKE Jiajun Institute of Chemical metallurgy,Academia Sinica,beijing,china

The anionic species of the SiO_2-containing sodium aluminate solutions prepared by different methods have been investigated by Raman spectra and ultraviolet *** was found that these solutions have different SiO_2-containing *** solution prepared by leaching in- dustrial sinter of soda-lime sintering process contains polvsilicate ions with Si-O-Si radicals.

关键词： silicate anion sodium aluminate solution Raman spectra

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面向多联体叶片的机器人喷涂无干涉路径规划

机械工程学报 2024年第1期60卷 210-219页

作者：漆琪刘礼祥杨吉祥丁汉华中科技大学智能制造装备与技术全国重点实验室武汉430074 中国航发沈阳黎明航空发动机有限责任公司沈阳110043

多联体叶片存在曲面复杂、叶片间距小等结构特点。等离子喷涂为铸造多联体叶片的重要工序,可使叶片表面强化与改性,其喷涂质量直接决定叶片的成品率与性能。现有的机器人等离子喷涂的路径生成主要依靠手动示教,而喷涂过程中的喷涂距离... 详细信息

多联体叶片存在曲面复杂、叶片间距小等结构特点。等离子喷涂为铸造多联体叶片的重要工序,可使叶片表面强化与改性,其喷涂质量直接决定叶片的成品率与性能。现有的机器人等离子喷涂的路径生成主要依靠手动示教,而喷涂过程中的喷涂距离与喷涂夹角无法量化导致喷涂质量不均且示教方法繁琐、效率低。基于此,提出一种面向多联体叶片的工业机器人等离子喷涂无干涉路径生成及光顺方法。首先,根据CAD模型,将多联体叶片型面转为非均匀有理B样条(NURBS)曲面,利用NURBS曲面解析特性,生成约束喷涂行距与喷涂叶片边缘距离的初始路径点;然后将喷涂焰流简化为方向包围盒,将干涉曲面转为三角面片,采用基于分离轴检测的方法进行碰撞干涉检测,生成考虑最小喷涂倾角约束的喷涂姿态。采用基于球面样条四元数插值变步长姿态优化方法进行姿态光顺,生成无干涉且路径光顺的喷涂路径。经过仿真与实验验证,提出干涉避免算法能有效避免喷涂过程中的干涉现象。对比未光顺路径,所提出算法机器人运行效率提高52.6%,机器人振动下降,运行更加平稳,其中关节加速度最大下降55.8%,最小下降2.9%,末端瞬时加速度最大下降39.6%,最小下降14.4%。

关键词：多联体叶片机器人喷涂干涉检测路径光顺

Electrochemical Characterization of Surface-modified LiMn_2O_4 Cathode Materials for Li-ion Batteries

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Journal of Wuhan university of technology(Materials science) 2006年第4期21卷 56-59页

作者：禹筱元 College of science South China Agricultural University Guangzhou 510642ChinaSchool of Physics & Engineering Sun Yat-sen University Guangzhou 510275China

To improve the performance, the surface of 12Mn2O4 was coated with very fine MgO , Al2O3 and ZnO by solgel method, respectively. The structure and morphology of the coated materials were investigated by X-ray diffraction （ XRD ）, X-ray photoelectron spectroscopy （ XPS ） and scanning electron microscopy （SEM）. The charge and discharge performance of uncoated and surfnce modified 12Mn2O4 spinel at 25℃ and 55 ℃ were tested, using a voltage window of 3.0-4.35 V and a current deasity of 0. 1 C rate. There is a slight decrease in the initial discharge capacity relative to that of uncoated UMn2 O4, bat the cycle ability of 12 12Mn2O4 coated by metal-oxide has remarkably been improved. The EIS measuremeuts of uncoated and Al2O3 -coated 12Mn2O4 were carried out by a model 273 A potentiostatl galvanistat controUed by a computer using M270 software, and using a freqnency response analyzer （ Zsimpwin ） combined with a potentiostate （ PAR 273）. Coaseqnently, the reason for the improved cycle properties is that the surface modification reduces the dissolution of Mn , which results from the suppression of the electrolyte decomposition, and suppresses the formation of passivation film that acts as an electronic insulating layer. In conclusion, the use of surface modification is an effective way to improve the electrochemical performance of 12Mn2O4 cathode material for lithium batteries.

关键词： lithium-ion batteries surface modification metal-oxide coating: 12Mn2O4 cathode

Structural Characteristics of Rapidly Quenched Al-Si Alloys

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Journal of Materials science & technology 1994年第3期10卷 232-234页

作者： Lin liu(Institute of Solid State Physics, Academia Sinica, Hefei, 230031, china)Yuanda DONG(Dept. of metallurgy and Materials, Shanghai university of technology, Shanghai, 200072, china) Inst of Solid State Physics Academia Sinica Hefei China

The structure of rapldly quenched Al-Si alloys (1 and 4 wt-%Si) was systematically studied by optical and transmission electron microscopy (TEM ) as welI as X-ray djffractjon (XRD). ExperimentaIresults show that rapid solidification refines the grain size. extends the solid solubility of Si in Al and Introduces a high density ot defects which exist in the forms of vacancies, dislocations and dislocation loops. etc.. The decomposition process of the alloys was fol lowed by using differential scanning calorimeter (DSC) and the activation energy for precipitation of Si was obtained through Kissinger analysis. The precipitation behaviour of Supersaturated Si in both samples was further examined by TEM. It was found that Si mainly precipitated inside the grains in Al-1 wt-%Si alloy. while in Al-4 wt-%Si alloy. nearly all the Si precipitates distributed along the grain boundaries. This may be due to the structure difference between the alloys in as-quenched state

关键词： Al Si Structural Characteristics of Rapidly Quenched Al-Si Alloys

SUPERPLASTIC BEHAVIOUR OF A FINE GRAINED TiAl BASED ALLOY TREATED BY MULTI-STEP THERMO-MECHANICAL TREATMENT

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中国有色金属学会会刊：英文版 1998年第1期8卷 108-109页

作者： Huang Baiyun, Deng Zhongyong and He YuehuiPowder metallurgy Research Institute,Central South university of technology, Changsha 410083, P. R. chinaSun Jian and liu QinDepartment of Materials science and EngineeringShanghai Jiao Tong university Powder metallurgy Research Institute Central South University of Technology Changsha 410083 China Department of Materials science and Engineering Shanghai Jiao Tong University Shanghai 200030 China

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关键词： TiAl forging superplasticity

Influence of Cooling Conditions in Casting Cu-Ni Alloy Based on Numerical Simulation

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Journal of Wuhan university of technology(Materials science) 2010年第1期25卷 68-72页

作者：庞玉华 school of metallurgy Engineering Xi'an University of Architecture &Technology

The most common and serious defect in Cu-Ni alloy casting is porosity. To solve the problem, accurate casting design and proper design of gating system are necessary. It can be predicted and designed by means of computer simulation of casting solidification. Based on the casting process of the Cu-Ni alloy, the simulation software of diathermanous—flowing—stress coupling ProCAST was used to simulate the Cu-Ni alloy solidification process about the defects and temperature field. By combining experimental results with the simulation results, the quality of casting on some cooling conditions were analyzed. Furthermore, a better cooling condition for solidification process of the Cu-Ni alloy was chosen to improve the quality of the casting. The simulation results indicate that the quality of Cu-Ni alloy casting is the best when it is on the cooling condition of the permanent mold with the insulated riser system.

关键词： cooling condition Cu-Ni alloy solidification numerical simulation proCAST

EVAPORATION KINETICS OF SnS FROM SnS-Cu_2S-FeS MELTS

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Acta Metallurgica Sinica(English Letters) 1999年第6期12卷 0-0,0-0+0-0+0页

作者： Y. X. Hua and C.P. liu(Depatment of metallurgy, Kunming university of science and technology, Kunming 650093, china)

The evaporation kinetics of SnS from SnSCu2SFeS teruary system was investigated against matte grade, tetnperature and carrier gas flow rate. It was demonstrated that the evapomtion process is controlled by gas-phase mass transport. The increases of the flow rote of carrier gas and the temperature could increase the gas-phase mass transport coefficient and the Partial pressure of SnS over the melts, respectively, and hence would appreciably promote the evaporation process. An increase of matte grade could lower the activitv coefficient of SnS in the melts, which in turn would cause the reduction of the evapomtion rate of SnS

关键词： evaporation kinetics SnS SnS-Cu_2S-FeS melt

Processing TiAl-Based Alloy by Elemental Powder metallurgy

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Journal of Materials science & technology 2000年第6期16卷 605-610页

作者： Yong liu, Baiyun HUANG, Yuehui HE and Kechao ZHOU (National Key Laboratory for Powder metallurgy, Central South university of technology, Changsha 410083, china) [Manuscript received July 31, 1999, in revised form November 19, 1999] Natl. Key Lab. for Powder metallurgy Central South Univ. of Technol. Changsha 410083 China

TiAI-based alloys with various compositions (including Ti-48Al, Ti-47Al-2Cr-2Nb, Ti-47Al-2Cr-2Nb-0.2B and Ti-47Al-3Cr, in mole fraction) had been prepared by elemental powder metallurgy (EPM). The results have shown that the density of the prepared Ti-48AI alloy increases with increasing hot pressing temperature up to 1300℃. The Ti-48AI alloy microstructure mainly consisted of island-like Ti3Al phase and TiAl matrix at hot pressing temperature below 1300℃, however, coarse α2/γ lamellar colonies and γ grains appeared at 1400℃. It has also indicated that the additions of elemental Cr and B can refine the alloy microstructure. The main microstructural inhomogeneity in EPM TiAI-based alloys was the island-like α2 phase or the aggregate of α2/γ lamellar colony, and such island-like structure will be inherited during subsequent heat treatment in (α＋γ) field. Only after heat treatment in a field would this structure be eliminated. The mechanical properties of EPM TiAl-based alloys with various compositions were tested, and the effect of alloy elements on the mechanical properties was closely related to that of alloy elements on the alloy microstructures. Based on the above results, TiAI-based alloy exhaust valves were fabricated by elemental powder metallurgy and diffusion joining. The automobile engine test had demonstrated that the performance of the manufactured valves was very promising for engine service.

关键词： TiAl Processing TiAl-Based Alloy by Elemental Powder metallurgy

Grain Refiner for TiAl Intermetallic Compounds

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Journal of Materials science & technology 1994年第3期10卷 205-208页

作者： Yuehui HE Yexiang liu Baiyun HUANG Xuanhui QU and Changming LEI (Powder metallurgy Research Institute, Central South university of technology, Changsha, 410083, china) Central South Univ of technology Changsha China

The effect of BN addition on the grain size and rnechanical properties of Ti-34.1 wt-%Al alloy was investigated. It has been found that BN is an effective grain refiner for TiAl base alloys, The addition of a small arnount of BN to TiAl can change the coarse columnar grains of as-cast rnicrostructure into the fine equiaxed grains. It has been also determined that Ti-34.1 wt-%Al-1.0 wt-%BN alloy has better mechanical properties and microstructure

关键词： TiAl AIME