Viscosities of Fe_nO-MgO-SiO_2 and Fe_nO-MgO-CaO-SiO_2 slags

1　INTRODUCTIONTheviscosityofliquidslagsisanimportantphysicalproperty .Innickelflashsmeltingprocesses ,slagscontainmainlyironoxidesandsilicainadditiontoMgO ,CaO ,Cr2 O3andAl2 O3aswellasvaluemet alsandotherimpurities .Manyinvestigationsontheviscosityofironsilicatemeltwerealreadyreport ed[14 ] .Butonlyfewstudiesarereportedontheslagsinthecompositionrangeoccurringinnickelmattesmelting.Thismaymainlybeattributedtoexperi mentaldifficultiesinviscositymeasurementsforthehighmeltingtemperatureofi…     

Effect of Cr doping on structure of LiMnO_2

1　INTRODUCTIONThelayeredLiCoO2 compoundhasbeensuccess fullycommercializedbecauseofitshighenergydensi tyanditsexcellentstabilitywithrespecttoextendedelectrochemicalcycling .However,fromtheeconomicandenvironmentalpointofview ,cheaper ,lessertox icandsaferintercalationmaterialsthanLiCoO2 com poundarerequired .LiMnO2 compoundsareofinterestasintercalationcathodesforrechargeableLibatteriesduetotheirhightheoreticalcapacity (2 85mAh/g) ,lowcostandnontoxicity .OrthorhombicLiMnO2 (o LiMnO2 ,…     

Application of annexation principle to the study of thermodynamic properties of ternary molten salts CaCl2-MgCl2-NaCl

Based on the practical basis of measured activities and phase diagrams as well as in the light of the mass action law, the model of inseparable cations and anions of molten salts and mattes, and the annexation principle of two kinds of solutions in binary melts, the calculating model of mass action concentrations of molten salts CaCl2-MgCl2-NaCl?A was formulated. The results of calculation not only agree with experimental values, but also obey the mass action law, testifying that the model formulated can embody the structural characteristics of these ternary salts, and that the model of inseparable cations and anions as well as the annexation principle of two kinds of solutions in binary melts are also applicable to these ternary salts.     

Application of annexation principle to the study of thermodynamic properties of ternary molten salts CaCl_2-MgC_2-NaCl

Based on the practical basis of measured activities and phase diagrams as well as in the light of the mass action law, the model of inseparable cations and anions of molten salts and mattes, and the annexation principle of two kinds of solutions in binary melts, the calculating model of mass action concentrations of molten salts CaCl_2-MgCl_2-NaCl was formulated. The results of calculation not only agree with experimental values, but also obey the mass action law, testifying that the model formulated can embody the structural characteristics of these ternary salts, and that the model of inseparable cations and anions as well as the annexation principle of two kinds of solutions in binary melts are also appficable to these ternary salts.     

Effects of surface modification on electrochemical performance of MnO2

The MnO2 samples coated with Ca（OH）2 were prepared by a liquid-phase surface treatment method. The physical properties of the samples were examined by SEM, EDAX and chemical analysis, and their electrochemical performances were investigated by means of galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy （EIS）. The SEM results show that the samples coated with Ca（OH）2 display a porous surface structure. The electrochemical experiments indicate that the surface modification decreases the polarization of MnO2 electrodes and improves their discharge potentials and discharge capacities.     

Effect of Heat-Treatment Parameters on Microstructures and Properties of Crl2W2MoVNbNB Steel

RECENTLY the refractory tube steels for thesupercritical and hyperhypercritical sets of heat powerplant,i.e.TB12and so on,whose structures consist ofthe tempering lath martensite and the blocky ferrite andwhose heat resistance is higher than that of P91/T91,have been developing in USA and in Europe.Thisresearch have been launched,and the new trialCrl2W2MoVNbNB steel,whose strength and thermalstability is superior to P91/T91steel which has beenwidely used in the foreign heat power plan…     

Studies of Composition and Structure of CO2 Corrosion Film of X56 Steel in the Medium of CO2 and Salt Water

The X56 steel samples was corroded in the medium of salt water solution at the conditions of CO2 partial pressure Pco2 0.5 to 2.0 MPa. temperature 80℃ and flow rate 1.4m/s. Corrosion weigh loss, composition and strutcture, morphology and phase of corrosion films of the samples were investigate by SEM, EDS, XRD and XPS. The results indicated that the corrosion degree was accelerated with increasing Pco2. The intense localised corrosion occurred on the surface of samples. The corrosion films mainly comprised of FeCO3 and complex phase products (Fe. Ca,...)CO3. There exists serious pitting on the metal substrates under the corrosion film. The theoretic and experimental analyses indicate this is caused by existed micropores or micro holes in films, which have the function of mass transportation.     

Charge-discharge process of MnO2 supercapacitor

Mechanochemical synthesis of α-MnO2 was carried out with KMnO4 and Mn（CH3COO）2 in 1：1 mole ratio. The electrochemical performance of MnO2 electrode was investigated by cyclic voltammograms and alternating current impedance. The charge-discharge process of MnO2 supercapacitor in 6 mol/L KOH was studied within 1.2 V at 200 mA/g, suggesting that it displays double-layer capacibility in low potential scope and pseudo-capacitance properties in high potential scope. It is found that Mn3O4, an electrochemical inert, mainly forms in the initial 40 charge-discharge cycles. During cycling, the pseudo-capacitance properties disappear and the discharge curves are close to ideal ones, indicating double-layer capability. The maximum capacitance of MnO2 electrode is as high as 416 F/g, and retains 240 F/g after 200 cycles. The equivalent series resistance increases from 17 to 41Ω.     

Effect of evolution of polycrystalline textures on r-value of LF2 aluminum alloy

The effect of evolution of polycrystalline texture on normal anisotropy coefficient r-value of aluminum alloy sheet was investigated. For this purpose, the textures under different elongation of LF2 aluminum alloy were measured and analyzed. The result indicates that the initial texture of LF2 aluminum alloy has the typical rolling texture, and the main components include Brass {011 } （2H）, Copper { 112}（111）and S{ 123}（634）. These three main components exhibit different transformation tendencies when the material specimens are stretched along the different direction. Based on Taylor model and Minor Work principle, the normal anisotropy coefficient r-values ofpolycrystalline aluminum alloy under various strain states were calculated. The result indicates that the r-values of LF2 aluminum alloy vary with tensile direction and the amount of deformation. The deformability on rolling direction is superior to the other direction because an enhancement tendency of r0 appears in tension process along rolling direction.     

Chemical synthesis of nanocrystalline ZrO_2-SnO_2 composite powders

ZrO_2-SnO_2 composite nanoparticles were prepared by heating the hydrate precursors synthesized by the chemicalco-precipitation reaction of ZrOCl_2 and SnCl_4. The precursors were examined by differential thermal analysis (DTA) andthermogravimetric analysis (TGA). The composite powder was characterized using X-ray diffraction (XRD), transmissionelectron microscopy (TEM) and desorption isotherm (Barrett-Joyner-Halenda method). The average crystal size of thenanoparticle ranges from 15 to 30 nm for the sample containing 5%-25% ZrO_2 (mass fraction). Most of the pores in theZrO_2-SnO_2 nanoparticles are about 10-20 nm in diameter. The composite powder is promising for chemical sensors.     

Degradation of crystal violet using nanometer TiO2 under the synergistic action of H2O2 and ultrasonic wave

TiO2 nanoparticles with different phases are prepared by hydrolysis of titanium tetrabutoxide in the presence of HCl. The composition and microstructure of the resulting samples are studied by XRD and TEM. These results show that the range of particle size of TiO2 is from 20 to 30 nm. The mechanism of TiO2 photocatalysis reaction has been discuss edextensively. Photocatalyfic activities of nanometer TiO2 are also evaluated by degradation of the crystal violet solution. Experimental results indicate that the synergistic action of H2O2 and ultrasonic wave greatly enhances photo-catalytic reaction of TiO2.     

Effects of tourmaline on microstructures and photocatalytic activity of TiO2/SiO2 composite powders

The SiO2/TiO2 composite powders including mineral tourmaline powders （T/SiO2/TiO2） were prepared from a sol made by a two-step hydrolysis method, using metasilicate ester as precursor. The powders were characterized by scanning electron microscopy （SEM）. The photocatalytic activity of the sample was evaluated by the photocatalytic degradation of methyl orange. The effects of heat-treatment on the photocatalytic activity were discussed. It is found that the T/SiO2/TiO2 composite powders show higher photocatalytic activity when including 10% SiO2 and 4% tourmaline. Moreover, the photocatalytic mechanism of tourmaline on the powders was proposed.     

Kinetics of high temperature deformation of lamellar Ti48Al–2Nb–2Cr

Based on microstructural observations, the deformation resistance of lamellar Ti48Al–2Nb–2Cr in the temperature range between 1000 and 1200 K is expressed by treating the material as a composite of regions with lamellar and globular structure deforming independently of each other. For stresses below 1000 MPa the dislocation velocity is lower in the lamellar regions compared to the globular ones due to a larger athermal hardening component caused by interfaces (lamella boundaries in the lamellar structure and (sub)grain boundaries in the globular structure). Combining deformation kinetics and structural evolution allows the modelling of the maximum deformation resistance and the subsequent softening resulting from the increase in globular volume fraction. The model is applied to predict the creep life.     

Behavior of 2-ethylhexanoic Acid in Organic Phase of Gallium Extraction

The rate of batch extraction of gallium from alkaline aqueous solution was studied by adding2-ethylhexanoic acid in organic phase containing 7-substituted-8-hydroxyquinoline(extractant N601),n-decanol and kerosene.The extraction of Ga can be considered as a pseudo-homogeneous first-order reac-tion.The neutralization and distribution of organic acid between phases during the extraction were studied.The effect of 2-ethylhexanoic acid on the protonation of N601 is insignificant.The extraction of HCl duringthe stripping of gallium is mainly dependent on the concentration of aqueous hydrochloric acid and the con-tent of N601.Under the given conditions of temperature and N601 content,the acidity of organic phase isa linear function of the concentration of carboxylic acid in organic phase and the concentration ofhydrochloric acid in equilibrium aqueous phase,if the latter is 1.9～5.6 mol/L.     

Synthesis of ZrO2-SiC composite powder and effect of its addition on properties of Al2O3-C refractories

ZrO2-SiC composite powder was synthesized by carbothermal reduction of zircon in argon atmosphere, and it was used as the additive to prepare Al2O3-C refractories. The effects of heating temperature on the synthesis process and the addition of the synthesized composite powder on the properties of the Al2O3-C refractories were investigated. The results show that the synthesized composite powder can be easily obtained by heating the mixture of zircon and carbon black at 1 873 K for 4 h in argon atmosphere, and the relative contents of ZrO2 and SiC in sample reach about 83.7% and 16.3%, respectively. The bulk density, crushing strength and thermal shock resistance of the Al2O3-C refractories can be improved obviously by the addition of the synthesized ZrO2-SiC composite powder.     

Effect of surfactants on preparation of nanometer TiO2 by pyrohydrolysis

The nanometer TiO2 was prepared by pyrohydrolysis with titanic solution.The effects of species and content of the surfactants on the particle size,morphology and phase of TiO2 were studied by using LPA,XRD and TEM respectively.The results show that it is beneficial to reducing the aggregation of TiO2 particles with adding surfactants to the solution.Nanometer TiO2 powders with the size of 40-55 nm are obtained by adding the anion surfactants in the optimal content of 1.5%(mass fraction).The effect of cationic surfactant for reducing particle aggregation is not as good as that of anion.The crystal phase constitutent of TiO2 is dependent on the temperature of thermal treatment and complete anatase can be achieved after calcining in the temperature range of 350-750℃.     

Preparation of RuO_2-SnO_2 nanomaterial by sol gel technique

1　ＩＮＴＲＯＤＵＣＴＩＯＮＰｒｅｃｉｏｕｓｍｅｔａｌｏｘｉｄｅｓｈａｖｅｂｅｅｎｔｈｅｆｉｒｓｔｃｈｏｉｃｅａｓａｎｏｄｅｍａｔｅｒｉａｌｓｉｎｅｌｅｃｔｒｏｃｈｅｍｉｃａｌｉｎｄｕｓｔｒｉｅｓ[1,2].ＲｕＳｎｂｉｎａｒｙｏｘｉｄｅｓｈａｖｅｅｘｃｅｌｌｅｎｔｅｌｅｃｔｒｏｃａｔａｌｙｓｉｓｐｒｏｐｅｒｔｉｅｓａｎｄｃｏｒｒｏｓｉｖｅｒｅｓｉｓｔａｎｃｅ.ＲｕＳｎｂａｓｅｄｏｘｉｄｅｓａｒｅｗｉｄｅｌｙｕｓｅｄａｎｏｄｅｃｏａｔｉｎｇｍａｔｅｒｉａｌｓｉｎｅｌｅｃｔｒｏｃｈｅｍｉｃａｌｉｎｄｕｓｔ…     

Effects of load mode on mechanical properties of ZrO_2(2Y)/TRIP steel composites

1　INTRODUCTIONArmourmaterialsbearthehigh speedstrikingload.Soitisbeneficialtotheballisticpropertiesofthematerialsbyimprovingtheabsorbedenergyunderdynamicloadorinducingthe phasetransformationstrengtheningduringtheabsorbingenergy pro cess[1,2 ] .Transformationinduced plasticitysteel(TRIP)hasthegoodtransformationplasticity ,highroomtemperaturestaticstrengthand goodweldingpropertyandisa promisingarmourmaterial[3,4 ] .ZrO2 hashighstrength ,highhardnessand goodchemicalconsistentpropertieswhe…     

Microwave synthesis of LiCoO2 cathode materials

1INTRODUCTION LiCoO2isacommerciallyusedcathodemateri alforlithiumionbattery.Comparedwithothercathodematerials,suchasLiNiO2,LiMn2O4and theirdopedcompounds,LiCoO2hastheadvanta gesofhighpotential,excellentreversibility,longcyclelifeandreliableperformance[14].Thereare mainlyseveralmethodsforsynthesisofLiCoO2,suchasconventionalceramicmethod[5,6],sol gel synthesis[7],andlow temperaturesolutioncom bustion[8].Amongthesemethods,theconvention alceramicmethodhasbeenappliedtoindustrial productio…