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Research on semi-solid slurry of a hypoeutectic Al-Si alloy prepared by low superheat pouring and weak electromagnetic stirring

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Rare Metals 2006年第2期25卷 177-183页

作者： LIU Zheng MAO Weiming ZHAO Zhengduo material of science and engineering School University of Science and Technology Beijing Beijing 100083 China Faculty of material and Chemical engineering Jiangxi University of Science and Technology Ganzhou 341000 China

The semi-solid slurry of a hypoeutectic Al-Si alloy was manufactured by low superheat pouring and weak electromagnetic stirring. The effects of pouting temperature and stirring power on the semi-solid slurry were investigated. The results indicated that the semi-solid slurry to satisfy rheocasting can be manufactured by low superheat pouring and weak electromagnetic stirring. The pouring temperature （or superheat） and the stirring power remarkably affected the morphology of primary α-Al and the size of primary α-Al, and there is no obvious effect of stirring time on primary α-Al. Compared with the samples made by low superheat pouring with no stirring, the nucleation rate, particle morphology and grain size of primary α-Al in A356 were markedly improved by low superheat pouring and weak electromagnetic stirring. On the condition of weak electromagnetic stirring, the pouring temperature with low superheat can be suitably raised to reach the effectiveness obtained from the lower pouring temperature without stirring.

关键词： semi-solid low superheat pouring weak electromagnetic stirring hypoeutectic Al-Si alloy A356 Al alloy

The Coagulation Process of Nascent Fibers in PAN Wet-spinning

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Journal of Wuhan University of Technology(materials science) 2010年第2期25卷 200-205页

作者：陈娟葛曷一 School of material science and engineering University of Jinan

The evolvement of microstructure and properties of nascent fibers during coagulation process in the polyacrylonitrile （PAN） wet-spinning and the effect of coagulation bath conditions on the structure and properties of the nascent fibers were investigated by the means of X-ray diffraction （XRD）, scanning electron microscope （SEM）, fiber fineness machine, fiber tensile strength machine, etc. The experimental results indicate that the nascent fibers become denser and have fewer inner defects, the diameter of nascent fibers shrink and the crystallization degree of nascent fibers gradually increases with the increasing of coagulation time. Too large spinning tension leads to grooves occurring on surface of fibers. To obtain circular cross-section of nascent fibers the optimal coagulation conditions are 50 ℃, 65% （concentration） and 0.9 （draw ratio）.

关键词： PAN wet-spinning coagulation nascent fibers

Dependence of Magnetic Properties of Rapidly Quenching (Nd,Pr)_x (FeCoZr)_(94-x)B_6 Bonded Magnets on Rare Earths Content

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Journal of Rare Earths 2004年第3期22卷 418-421页

作者：查五生刘颖高升吉连利仙涂铭旌 College of material science & engineering Sichuan University Chengdu 610065 China College of material science & engineering Xihua University Chengdu 610039 China

By using sub-overquenching and annealing method which has a wide processing window, (Nd, Pr), ( Fe-CoZr)(94-x)B-6(x = 12, 10.5, 10, 9) bonded magnets were prepared and the effect of rare earths content on magnetic properties was investigated. Being spun at *** speed the as-spun ribbons consist of amorphous phases mixed with fine crystallites. After crystallization under optimum annealing conditions and bonded with 3.25% (mass fraction) epoxy, the magnets obtained the optimum magnetic properties. The rare earths content directly determines the magnetic properties. With the reduction of rare earths content, B-r increases but H-ci and (BH)(max) decrease. x = 10 is the critical value for the magnetic proper-ties change. Below this value, Br increases slowly meanwhile H-ci and (BH)(max) decrease strongly because alloy contains extra fractions of soft magnetic phase which are not coupled with the hard magnetic phase.. This experimental result is consistent with the calculated results using the model of volume fraction of soft magnetic phase coupled completely suggested.

关键词： metal materials Pr-based permanent magnets nanocrystalline composite magnetic properties completely coupling model rare earths

通过受控晶体应变揭示PtCo双金属固体溶液中增强的氧还原活性（英文）

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science China materials 2025年第01期 180-188页

作者：贺宁吴胜强俞文松金方润谢文俊鲁欣欣赵晓续陈仲欣涂文广唐叔贤 School of science and engineering The Chinese University of Hong Kong School of materials science and engineering Peking University School of materials science and engineering Huaqiao University Petro China Shenzhen New Energy Research Institute Institute of materials science and Devices Suzhou University of Science and Technology

开发用于氧还原反应（ORR）的低成本、高活性铂（Pt）基电催化剂对于燃料电池的广泛应用至关重要.一种有效的方法在于将Pt与非贵过渡金属合金化,以调节Pt表面的物理化学状态.然而,由于合金化过程中成分、晶体类型和表面结构的复杂性,在...

开发用于氧还原反应（ORR）的低成本、高活性铂（Pt）基电催化剂对于燃料电池的广泛应用至关重要.一种有效的方法在于将Pt与非贵过渡金属合金化,以调节Pt表面的物理化学状态.然而,由于合金化过程中成分、晶体类型和表面结构的复杂性,在理解结构-性能关系方面仍然存在巨大挑战.在本研究中,我们使用液相合成方法合成了一系列不同比例的PtCo双金属固溶体.通过利用固溶体的特性,所得的PtCo双金属合金保持了面心立方晶体结构,最大限度地减少了合金化过程中引入的复杂性,有利于活性机理分析.此外,在受控合金成分和晶体结构下,我们研究了氧还原反应的电催化活性对铂催化剂表面应变的依赖性.据此设计的S-PtCo-SNPs阴极赋予了质子交换膜燃料电池（PEMFC）(2.08 W cm-2,4 A cm-2)和锌-空气电池（ZAB）(143.1m W cm-2,214.5m A cm-2)出色的性能.

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Growth and Chemical Thermodynamics Analysis of SiC Film on Si Substrate by Heating Polystyrene/Silica Bilayer Method

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Chinese Journal of Chemical Physics 2008年第2期21卷 151-155页

作者： Yun Li Yu-xia Wang Zheng Chen Jian-wen Wang You-ming Zou Department of material science and engineering University of Science and Technology of China Hefei 230026 China

SiC films were prepared by modified heating polystyrene/silica bilayer method on Si（111） substrate in normal pressure flowing Ar ambient at 1300℃ . The films were investigated by Fourier transform infrared absorption, X-ray diffraction, and scanning electron microscopy measurements. The chemical thermodynamics process is discussed. The whole reaction can be separated into four steps. The carburizing of SiO is the key step of whole reaction. The main reaction-sequence is figured out based on Gibbs free energy and equilibrium constant. Flowing Ar is necessary to continue the progress of whole reaction by means of carrying out accumulating gaseous resultants. The film is very useful for application in a variety of MOS-based devices for its silica/SiC/Si（111） structure, in which the silica layer can be removed thoroughly by the standard RCA cleaning process.

关键词： Thin film Heat treatment Silicon carbide Chemical thermodynamics Silicon monoxide

Experimental study on new method and automatic system for fast evaluating Al-Si alloy modification effect in front of furnace

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science China(Technological sciences) 2006年第5期49卷 569-575页

作者： SHI Dequan LI Dayong GAO Guili WANG Lihua School of material science and engineering Harbin University of Science and Technology Harbin 150040 China School of Material Science and Engineering Harbin University of Science and Technology Harbin 150040 China School of Material Science and Engineering Harbin University of Science and Technology Harbin 150040 China School of Material Science and Engineering Harbin University of Science and Technology Harbin 150040 China

A new method based on the surface tension measurement for fast evaluating modification effect of Al-Si alloy in front of furnace and an automatic system for fast measuring surface tension of molten Al-Si alloy are introduced. By theoretical analysis the relation between surface tension σe of molten Al-Si alloy and information parameters △P , N , φx and T has been established, namely, σ e = a △P + b . N + c . (φ x- φ0)+ d . T +e . By ex- periments the relationship between surface tension and modification level of Al-Si alloy has been also got that σ e > 530 mN/m, 400 ≤σe ≤530 mN/m and σ e < 400 mN/m are corresponding with AFS 1-2, AFS 3-4 and AFS 5-6 of Al-Si modification effect. Depending on the conclusions, modification effect can be recognized in a few seconds, which is of practical significance for real-time evaluating modification effect of Al-Si alloy in front of furnace.

关键词： surface tension, modification effect, new method, automatic testing system.

Nitrogen and Phosphorus Dual-Doped Multilayer Graphene as Universal Anode for Full Carbon-Based Lithium and Potassium Ion Capacitors

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Nano-Micro Letters 2019年第2期11卷 166-178页

作者： Yuting Luan Rong Hu Yongzheng Fang Kai Zhu Kui Cheng Jun Yan Ke Ye Guiling Wang Dianxue Cao Key Laboratory of Superlight material and Surface Technology of Ministry of Education College of Material Science and Chemical EngineeringHarbin Engineering University

Lithium/potassium ion capacitors(LICs/PICs) have been proposed to bridge the performance gap between high-energy batteries and high-power ***,their development is hindered by the choice,electrochemical performance,and preparation technique of the battery-type anode ***,a nitrogen and phosphorus dual-doped multilayer graphene(NPG) material is designed and synthesized through an arc discharge process,using low-cost graphite and solid nitrogen and phosphorus *** employed as the anode material,NPG exhibits high capacity,remarkable rate capability,and stable cycling performance in both lithium and potassium ion *** excellent electrochemical performance is ascribed to the synergistic effect of nitrogen and phosphorus doping,which enhances the electrochemical conductivity,provides a higher number of ion storage sites,and leads to increased interlayer *** carbon-based NPG‖LiPF6‖active carbon(AC) LICs and NPG‖KPF6‖AC PICs are assembled and show excellent electrochemical performance,with competitive energy and power *** work provides a route for the large-scale production of dual-doped graphene as a universal anode material for high-performance alkali ion batteries and capacitors.

关键词： Arc discharge Graphene Heteroatom doping Lithium/potassium ion battery Lithium/potassium ion capacitor

Electric transmission behavior of self-assembled Cu–W nano multilayers

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Progress in Natural science:materials International 2021年第1期31卷 25-32页

作者： Mengzhao Yang Tianle Xie Licai Fu Jiajun Zhu Wulin Yang Deyi Li Lingping Zhou College of material science and engineering Hunan University

Metallic nano multilayers were usually prepared by dual targets alternating deposition method. In this paper, a series of self-assembled Cu–W nano multilayers with different modulation periods were deposited on single crystal silicon substrate by dual targets confocal magnetron sputtering technique. The self-assembled film presented an alternation of W-rich layer and Cu-rich layer. The degree of coherence of the layered interface can be adjusted by controlling both the solid solubility of W-rich and Cu-rich layers. The film resistance increment of the self-assembled Cu–W multilayers is only 14% when the modulation period decreases from 68.2 nm to 5.3 nm,having less size effect compared to the film prepared by alternating deposition method. It noticed that the film resistance even decreased slightly when the modulation period decreased to below 5.3 nm. These results suggested that the coherence could weak the interface scattering ability to electrons, so the self-assembled Cu–W multilayers have lower resistance than the multilayer prepared by alternating deposition technique. This study presented a new pathway to enhance the conductivity of the multilayers.

关键词： Self-assembling Cu–W nano Multilayer Resistivity Interface F–S model

Electrospun composites of PHBV/pearl powder for bone repairing

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Progress in Natural science:materials International 2015年第4期25卷 327-333页

作者： Jingjing Bai Jiamu Dai Guang Li College of material science and engineering Donghua University

Electrospun fi ber has highly structural similarity with natural bone extracelluar matrix(ECM). Many researches about fabricating organic–inorganic composite materials have been carried out in order to mimic the natural composition of bone and enhance the biocompatibility of materials. In this work, pearl powder was added to the poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV) and the composite nano fi ber scaffold was prepared by electrospinning. Mineralization ability of the composite scaffolds can be evaluated by analyzing hydroxyapatite(HA)formation on the surface of nano fi ber scaffolds. The obtained composite nano fi ber scaffolds showed an enhanced mineralization capacity due to incorporation of pearl powder. The HA formed amount of the composite scaffolds was raised as the increase of pearl powder in composite scaffolds. Therefore, the prepared PHBV/pearl composite nano fi ber scaffolds would be a promising candidate as an osteoconductive composite material for bone repairing.

关键词： Hydroxyapatite Pearl PHBV Mineralization Composite nano fi bers scaffolds