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Wear Mechanism of WC-Co Cemented Carbide Tool in Cutting Ti-6Al-4V Based on Thermodynamics

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Journal of Wuhan University of Technology(Materials Science) 2020年第5期35卷 973-979页

作者： HU Xiaolong SHAO Fang WANG Renwei guizhou institute o f Technology Guiyang 550003China School o f Mechanical engineering Guizhou UniversityGuiyang 550025China School o f Mechanical engineering Shandong UniversityJinan 250100China

In order to optimize the tool coating material and reduce the tool wear rate,the coating material and wear mechanism for carbide tools are proposed and analyzed based on thermodynamics *** deduced the Gibbs free energy function method and analyzed the enthalpy value of the coating material of cemented carbide *** rules of diffusion wear and oxidation wear for WC-Co-based carbide tools were analyzed based on the diffusion dissolution theory and the calculation method of the thermal effect of chemical *** diffusion wear and oxidation wear of WC-Co-based carbide tools when machining Ti-6Al-4V were studied with *** results indicate that a good prediction accuracy of both diffusion wear and oxidation wear can be achieved by the method of thermodynamic theory analysis *** conclusion will provide useful references for the optimization of cutting parameters and the improvement of the tool life.

关键词： cemented carbide thermodynamics titanium alloy wear mechanism

Facile synthesis and enhanced visible-light photocatalytic activity of Ti3 ＋-doped Ti02 sheets with tunable phase composition

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Frontiers of chemical Science and engineering 2015年第3期9卷 349-358页

作者： Xiaojie Zhang Lei Wang Shuqing Chen Yi Huang Zhuonan Song Miao Yu Department of chemical engineering and Catalysis for Renewable Fuels (CReF) Center University of South Carolina Columbia SC 29208 USA Department of metallurgical and chemical engineering Jiyuan Vocational and Technical Collage Jiyuan 459000 China State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China

Ti3＋-doped TiO2 nanosheets with tunable phase composition （doped TiO2 （A/R）） were synthesized via a hydrothermal method with high surface area anatase TiO2 nanosheets TiO2 （A） as a substrate, structure directing agent, and inhibitor; the activity was evaluated using a probe reaction-photocatalytic CO2 conversion to methane under visible light irradiation with H2 as an electron donor and hydrogen source. High-resolution transmission electron microscope （HRTEM）, field emission scanning electron microscope, UV-Vis diffuse reflectance spectra, and X-ray diffraction （XRD） etc., were used to characterize the photocatalysts. XRD and HRTEM measurements confirmed the existence of anatase-rutile phase junction, while Ti3-and single-electron-trapped oxygen vacancy in the doped TiO2 （A/R） photocatalyst were revealed byelectron paramagnetic resonance （EPR） measurements. Effects of hydrothermal synthesis temperature and the amount of added anatase TiO2 on the photocatalytic activity were elucidated. Significantly enhanced photo- catalytic activity of doped TiO2 （A/R） was observed; under the optimized synthesis conditions, CH4 generation rate of doped TiO2 （A/R） was 2.3 times that of Ti3＋-doped rutile TiO2.

关键词： Ti3+-doped TiO2 photocatalytic CO2 conversion visible light irradiation

Study on the pre-treatment of oxidized zinc ore prior to flotation

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International Journal of Minerals,Metallurgy and Materials 2018年第2期25卷 117-122页

作者： Dong-sheng He Yun Chen Ping Xiang Zheng-jun Yu J.H.Potgieter School of Resource and Civil engineering Wuhan Institute of TechnologyWuhan 430205China Hunan Huaqi Resources and Environment Science&Technology Development Co.Ltd. Zhuzhou 412005China School of chemical and metallurgical engineering University of the WitwatersrandJohannesburg 2050South Africa

The pre-treatment of zinc oxide bearing ores with high slime content is important to ensure that resources are utilized optimally. This paper reports an improved process using hydrocyclone de-sliming, dispersion reagents, and magnetic removal of iron minerals for the pre-treatment of zinc oxide ore with a high slime and iron content, and the benefits compared to traditional technologies are shown. In addition, this paper investigates the damage related to fine slime and iron during zinc oxide flotation, the necessity of using hydrocyclone de-sliming together with dispersion reagents to alleviate the influence of slime, and interactions among hydrocyclone de-sliming, reagent dispersion, and magnetic iron removal. Results show that under optimized operating conditions the entire beneficiation technology results in a flotation concentrate with a Zn grade of 34.66% and a recovery of 73.41%.

关键词： zinc oxide ores flotation hydrocyclone de-sliming magnetic deferrization

Influence of chemical modification by Y2O3 on eutectic Si characteristics and tensile properties of A356 alloy

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Transactions of Nonferrous Metals Society of China 2019年第7期29卷 1365-1374页

作者： M. E. MOUSSA S. EL-HADAD W. KHALIFA Department of Casting Technology Central metallurgical Research and Development institute (CMRDI) P. O. 87 Helwan Egypt Department of Mining Petroleum and Metallurgical Engineering Faculty of Engineering Cairo University P. O. 12613 Giza Egypt

The modification of A356 aluminum-silicon alloy using yttrium oxide (Y2O3) was studied. Addition levels of up to 2.5 wt.% Y2O3 were investigated. A premixed powder of Al-30wt.%Y2O3 was added to the melt at about 750℃ using vortex method. Samples were then poured in sand mold. The results showed that evident modification was obtained using the Y2O3 addition. The optimum level was 1.5 wt.%, and was corresponding to a eutectic temperature depression from 568 to 557℃. The eutectic Si particles were refined in length from 44.8 to 8.3 μm, and modified in aspect ratio from 6.8 to 0.98. Higher additions of Y2O3 caused de-modification of the eutectic Si particles. The ductility of the modified specimens was enhanced by more than 20% compared to the unmodified ones. This was associated with a gradual transfer from cleavage to a more ductile mode of fracture.

关键词： hypoeutectic Al-Si alloys modification yttrium oxide (Y2O3) ductility fracture mode

Synthesis and characterization of high ceramic yield polycarbosilane precursor for SiC

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Journal of Advanced Ceramics 2015年第4期4卷 307-311页

作者： Mangesh LODHE Narendra BABU A.SELVAM M.BALASUBRAMANIAN Department of metallurgical and Materials engineering Indian Institute of Technology MadrasChennai 600036India FRP institute Chennai 600032India

The polycarbosilane(PCS)precursor for SiC with high molecular weight and medium molecular weight distribution was synthesized from polydimethylsilane at normal *** chemical formula,the number average molecular weight,and the polydispersivity index of the synthesized PCS are SiC_(1.94)H_(5.01)O_(0.028),1135,and 1.66,respectively,which can be attributed to the higher reaction temperature used for *** polymer to ceramic conversion of PCS was completed at 900℃with a ceramic yield of 85%.The crystallization started at 1100℃,and at 1200℃,well resolved peaks ofβ-SiC were formed with small amount ofα-*** X-ray diffraction(XRD)and transmission electron microscopy(TEM)studies indicated the presence of nanocrystallineβ-SiC.

关键词： synthesis polycarbosilane(PCS) polymer-ceramic conversion X-ray diffraction(XRD)

Electrostatic concentration of phosphate flotation concentrate

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International Journal of Mining Science and Technology 2013年第3期23卷 403-406页

作者： Bada Samson Gcanga Sandi Falcon Lionel Falcon Rosemary Makhula Mpho School of chemical and metallurgical engineering Faculty of Engineering and the Built Environment University of the Witwatersrand Department of Mineral Processing Mintek Randburg 2125 South Africa

The concentration of phosphate flotation concentrate with P2O5 grade lower than the commercially acceptable phosphate quality was upgraded in the use of tribo-electrostatic technique. The concentration of the flotation concentrate stream was conducted under both triboelectrification and inductive charging mechanism. Mineralogical analysis reveals that the phosphate ore utilized was dominated mainly by fluorapatite, crandallite, wavellite, and with quartz as the major gangue mineral. Flotations concentrate of about 28.87% P2O5 was obtained from the reverse flotation technique, after conditioning the phosphate ore at 80% passing 150 lm under Lilafloat. Constant parameters such as à6 kV charging voltage, 25 kV separating voltage, inlet air, different charger rotary speed and splitter distances were investigated. Commercially accepted grade of 35.50% P2O5 was attained after the second stage of separation with a recovery of 12.26%, another phosphate product of 34.02% P2O5 and 85.19% was also recovered under the same condition. Single stage of separation also shows a significant increase in the grade of the product obtained, with 33.41% P2O5 and 84.07% recovery achievable. The practicability of tribo-electrostatic separation technique for upgrading flotation concentrates resulted in a significant increase in grade for <150 lm product that do not meet the viable grade.

关键词： Dry beneficiation Fluorapatite-phosphate Mineralogy Reverse flotation Triboelectrostatic

A flexible solid polymer electrolyte enabled with lithiated zeolite for high performance lithium battery

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Nano Research 2023年第7期16卷 9443-9452页

作者： Zhiyu Ding Qiming Tang Qi Zhang Penghui Yao Xingjun Liu Junwei Wu Shenzhen Key Laboratory of Advanced Materials Department of Materials Science and EngineeringHarbin Institute of Technology(Shenzhen)Shenzhen 518055China Maryland Energy Innovation institute University of MarylandCollege ParkMD 20742USA Department of chemical and metallurgical engineering Aalto UniversityKemistintie 1Aalto FI-00076Finland

Solid-state lithium batteries using composite polymer electrolytes(CPEs)have attracted much attention owing to their higher safety compared to liquid electrolytes and flexibility compared to ceramic ***,their unsatisfactory lithium-ion conductivity still limits their ***,a high ion conductive CPE with multiple continuous lithium pathways is *** new electrolyte consists of poly(vinylidene fluorideco-hexafluoropropylene)(PVDF-HFP)and lithiated X type zeolite(Li-X),which possesses a high ionic conductivity(1.98×10^(-4)S/cm),high lithium transference number(t_(Li^(+))=0.55),wide electrochemical window(4.7 V),and excellent stability against the lithium *** functional theory(DFT)calculation confirms that the Lewis acid sites in zeolite can graft with N,N-dimethylformamide(DMF)and PVDF-HFP chains,resulting in decreased crystallinity of polymer and providing rapid Li+transmission *** used in a full cell,the solid Li|Li-X-3%|LiFePO_(4) cell displays excellent cycling stability and rate performance at room temperature and 60℃.Furthermore,pouch cells with the Li-X-3%electrolyte exhibit brilliant safety under extreme conditions,such as folding and ***,this proposed zeolite-PVDF-HFP CPE represents a promising potential in the application of making a safer,higher performing,and flexible solid-state lithium battery.

关键词： solid-state lithium batteries composite polymer electrolytes zeolite poly(vinylidene fluorideco-hexafluoropropylene)(PVDF-HFP) flexible

Germanium transport across supported liquid membrane with Cyanex 923: Mathematical modeling

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Transactions of Nonferrous Metals Society of China 2019年第9期29卷 1956-1966页

作者： Hossein KAMRAN HAGHIGHI Mehdi IRANNAJAD Ana MARIA SASTRE Department of Mining and metallurgical engineering Amirkabir University of TechnologyTehranIran Department of chemical engineering Universitat Politècnica de CatalunyaESTEIBAv.Diagonal 64708028 BarcelonaSpain

A mathematical model was developed to monitor the facilitated transport of germanium(IV) from oxalic acid solutions through a flat sheet supported liquid membrane(FSSLM) containing four trialkylphosphine oxides(Cyanex 923). The FSSLM modeling was based on the extraction constant(Kext) calculated from the liquid-liquid extraction(LLX) modeling. The LLX model presented a reliable calculation of the extraction constant(Kex= 2.057×103 L/mol4). The FSSLM model was solved using Matlab■ software according to extraction constant, Fick’s law, and diffusional principles. The model predicts the overall mass transfer coefficient(Korg) to be 3.84 cm/s. Using this value, diffusion coefficients(Dm) for various Cyanex 923 concentrations of 0.126, 0.252, 0.378, 0.505, 0.631 and 0.757 mol/L are found to be 8.50×10^-4, 4.30×10^-4, 1.87×10^-4, 5.87×10^-5, 2.57×10^-5, 2.09×10^-5 cm2/s, respectively. The results show that the diffusion rate of the current study is approximately more than that of similar FSSLM systems containing Cyanex 923 used to transport various metals. The modeling values are in good agreement with the experimental data, showing the good reliability of the mathematical model.

关键词： supported liquid membrane Cyanex 923 germanium transport mathematical modeling

Highly soluble organic nitrate additives for practical lithium metal batteries

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Carbon Energy 2023年第1期5卷 16-24页

作者： Zhe Wang Li-Peng Hou Zheng Li Jia-Lin Liang Ming-Yue Zhou Chen-Zi Zhao Xiaoyuan Zeng Bo-Quan Li Aibing Chen Xue-Qiang Zhang Peng Dong Yingjie Zhang Jia-Qi Huang Qiang Zhang Advanced Research institute of Multidisciplinary Science Beijing Institute of TechnologyBeijingPR China College of chemical and Pharmaceutical engineering Hebei University of Science and TechnologyShijiazhuangPR China School of Materials Science and engineering Beijing Institute of TechnologyBeijingPR China Beijing Key Laboratory of Green chemical Reaction engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijingPR China National and Local Joint engineering Laboratory for Lithium-Ion Batteries and Materials Preparation Technology Key Laboratory of Advanced Battery Materials of Yunnan ProvinceFaculty of Metallurgical and Energy EngineeringKunming University of Science and TechnologyKunmingPR China

The stability of lithium metal anodes essentially dictates the lifespan of high-energy-density lithium metal *** nitrate(LiNO_(3))is widely recognized as an effective additive to stabilize lithium metal anodes by forming LiN_(x)O_(y)-containing solid electrolyte interphase(SEI).However,its poor solubility in electrolytes,especially ester electrolytes,hinders its applications in lithium metal ***,an organic nitrate,isosorbide nitrate(ISDN),is proposed to replace LiNO_(3).ISDNhas a high solubility of 3.3M in ester electrolytes due to the introduction of organic segments in the *** decomposition of ISDN generates LiN_(x)O_(y)-rich SEI,enabling uniform lithium *** lifespan of lithium metal batteries with ISDN significantly increases from 80 to 155 cycles under demanding ***,a lithium metal pouch cell of 439Whkg^(−1) delivers 50 *** work opens a new avenue to develop additives by molecular modifications for practical lithium metal batteries.

关键词： electrolyte additives lithium metal anodes organic nitrate pouch cells solid electrolyte interphase