Growth and Application of Chalcogenides of Lead and Related Compounds

Large grain, low-dislocation, high-quality single crystals of various Pb-salt compounds have been grownreproducibly by the Horizontal Unseeded Vapor Growth (HUVG) technique. The Tunable Diode Lasers withbetter performance have been made with such crystals. The annealing feature, dislocations and diffusion in thecrystals have also been investigated.     

Intensifying digestion of diaspore and separation of alumina and silica

1　INTRODUCTIONDespitetheabundantdepositofbauxitesinChi na ,ofthosepredominantisthediasporictypewithhighalumina ,highsilicaandlowferricoxides .Thebauxitedeposit,withthemassratioofaluminatosil ica(A/S)between 4and 8,accountsfor 80 %ofallthebauxitedeposit.Thenatureofhighsilicacontentdeterminesthatthemainlyadoptedtechniquetopro ducealuminainChinashouldbeBayer sinteringcom binationprocessorevenpuresinteringprocess .Althoughadramaticadvancementinaluminaproductionhasbeenachievedandthetechnolo…     

Synthesis and purification of trialkyl compounds of gallium and indium

The research progress in trialkyl compounds of gallium and indium was discussed from two aspects, one was the chemical synthesis of the compounds and the other was the purification of them. There are three synthesis routes being reported in the first aspect, i.e. the route staring from pure metal, the route starting from the pure metal trihalides, and the electrochemical route. In the second aspect, the purifying methods of decomposition-distillation and zone refining were reviewed.     

Effect of Y on structure and properties of copper and its alloy

The possibility of substituting 72.5Cu-22.7Zn-3.4Al brass for phosphorus bronze in some case that is now extensively used for elastic component, and purifying the scrap copper for recycling metal was investigated. By adding a little amount of rare earth Y into scrap copper and 72.5Cu-22.7Zn-3.4Al brass to research their structure and characteristics, especially the electric conductivity for scrap copper and HV for the brass were researched. The results show that the tensile strength, elongation and electric conductivity （IACS） of 0.38 mm strip of scrap copper with 0.04% Y, are 213.8 MPa, 23% and 98.5% that suit for the elastic components. The tensile strength, elongation and HV of 0.25mm strip of the brass with 0.03% Y are 665.1MPa, 2.86% and 226 that satisfy the usage requirement for the elastic components. Meanwhile, the cost is cheaper than phosphorous bronze because of implying 22.7% zinc in the brass, which has the actual application value.     

Comparison of microstructure and corrosion properties of Al-Zn-Mg-Cu alloys 7150 and 7010

The influence of coarse Cu-bearing particles, matrix and subgrain boundary precipitates on the stress corrosion susceptibility of the Al-Zn-Mg-Cu alloys was investigated. The strength of 7150 alloy is about 15 MPa higher than that of 7010 alloy. The 7010 alloy exhibits higher resistance to stress corrosion cracking as compared with the 7150 alloy. The coarse Cu-bearing particles are detrimental to the resistance to stress corrosion cracking. The increase of size of matrix and subgrain boundary precipitates decreases the susceptibility of stress corrosion. The anodic dissolution and hydrogen embrittlement govern the cracking process. The severity of stress corrosion cracking is shown to be related to the coarse Cu-bearing particles, matrix and subgrain precipitates in Al-Zn-Mg-Cu alloys.     

Microstructure and properties of composite of stainless steel and partially stabilized zirconia

1　ＩＮＴＲＯＤＵＣＴＩＯＮＯｗｉｎｇｔｏｔｈｅｒｅｑｕｉｒｅｍｅｎｔｓｏｆｒｅｐｅａｔｅｄｓｅｒｖｉｃｅａｎｄｌｏｎｇｗｏｒｋｉｎｇｔｉｍｅｏｆｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｂｕｒｎｅｒｓ ,ｓｕｃｈａｓｓｐａｃｅｃｒａｆｔｅｎｇｉｎｅ ,ｔｈｅｍａｔｅｒｉａｌｏｆｔｈｅｂｕｒｎｅｒｓｓｈｏｕｌｄｈａｖｅｇｏｏｄｓｔｒｕｃｔｕｒｅｐｒｏｃｅｓｓａｂｉｌｉｔｙ ,ａｓｗｅｌｌａｓｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｒｅｓｉｓｔａｎｃｅ ,ｔｈｅｒｍａｌｓｈｏｃｋｒｅｓｉｓｔａｎｃｅａｎｄｔｈｅｒｍａｌｆａｔｉ…     

Measurement of surface crystallinity of PAA and PAANa coatings and its effect on hydrophilicity of coatings

1　INTRODUCTIONAsanimportantwater solublemacromoleculecompound,poly (acrylicacid) (PAA)anditssaltshavebeenwidelyused[1] .Utilizingitsfinefilm form ingcapacityandhydrophilicity ,Okoroaforetal[2 ] ,andPanetal[3] developedanewhydrophilicpaintforaluminiumfin[2 ,3] .Hydrophilic paintforheat ex changerofairconditioningdemandslittlesurfacecon tactangle ,sothatcontinuoushomogeneouswaterfilmcanformeasily ,andcandrainoffcondensedwa teronthesurfaceoffintimely[4 6 ] .Hydrophilicityofcoatingsisaffec…     

The Influence of Method of Carburizing and Nitrocarburizing on the Microstructure and Properties of Tool Steels

The paper presents the results of wear and metallography tests of tool steel grades: ASTM A681, ChI2M and Ch12FS per GOST, AMS 6437E i BS X46Cr13, all surface hardened by the Carbo process (carburizing) and by the NiCar process (nitrocarburizing). The therrno-chemical treatment was conducted in powder pack for a duration of 6 h (carburizing) and for 4 h in the case of nitrocarburizing. Factors investigated were: morphology, depth and microhardness of the cases obtained, their microstructure, as well as phase composition. Wear tests were conducted by the three cylinder-cone method.Wear velocity was 0.58 m/s, unit load was 50 MPa and 400Mpa, wear path was 3470 m. Oil SAE30 was applied at the rate of 30 drops per minute.     

Effect of sintering temperature and composition on microstructure and properties of PMS-PZT ceramics

The piezoelectric ceramics xPb（Mn1/3Sb2/3）O3-（1-x）Pb（Zr1/2Ti1/2）O3 （abbreviated as PMS-PZT） were synthesized by traditional ceramics process. The effect of sintering temperature and the amount of Pb（Mn1/3Sb2/3）O3 （abbreviated as PMS） on phase structure, microstructure, piezoelectric and dielectric properties of PMS-PZT ceramics was investigated. The results show that the pure perovskite phase is in all ceramics specimens, the phase structure of PMS-PZT ceramics changes from tetragonal phase to single rhombohedral phase with the increasing amount of PMS. The dielectric constant εr, Curie temperature Tc, electromechanical coupling factor kp and piezoelectric constant d33 decrease, whereas the mechanical quality factor Qm and dielectric loss tanδ increase with the increasing amount of PMS in system. The optimum sintering temperature is 1 200-1 250 ℃. It is concluded that the PMS-PZT （x=0.07） ceramics sintered at 1 250 ℃ is suitable for high-power piezoelectric transformer. These properties include εr=674.8, tanδ =0.005 25, kp=0.658, Qm= 1 520, d33=230 pC/N, Tc=275 ℃.     

Viscosity of In and In-Sballoys

The dynamic viscosity of pure In, In-1%Sb (mass fraction, so as the follows) alloy, In-55%Sb hypoeutectic alloy and In-69.5%Sb eutectic alloy was measured by using a torsional oscillation viscometer at different temperatures above liq-uidus. The experimental results show that the viscosity of these melts decreases with increasing temperature. The anomalous change of viscosity occurs at about 430 and 470℃in pure In melt. The variation of viscosity with temperature well meets exponential correlation and no anomalous change occurs in measured temperature range in the In-1%Sb alloy melt. A transition occurs at about 800℃ in both of In-55%Sb and In-69.5%Sb alloy melts. The sudden change of viscosity suggests the structure change of melts. DSC (differential scanning calorimetry) curves of In-1%Sb alloy during heating and cooling were measured, and the results show that no structural variation in In-1%Sb alloy melt was testified further. In addition, the viscosity of In melt decreases with the addition of1%S     

Test and analysis of mechanism and influential elements of axial drifting of weldment on turning rolls

0　IntroductionTheweldingturningrollsismainlyusedforweldingassemblyofcylindricalweldingcomponents.Duetode viationinfabricationandassemblyofweldingturningrollsandgeometricirregularityofweldment,theweld mentthrobsaxiallywhileitrollsontheweldingturningrolls .Itwillinfluencetheweldingqualityandbreaknor malweldingprocedure .Intheworstcases,theweld mentfallsdownfromtheweldingturningrollsandcaus esaccident.Akindofweldingturningrollsagainstaxialdriftinghasbeeninventedabroadinthemiddleof 1980andhasbee…     

Effect of cooling rate and composition on microstructures and properties of Zn-Mg alloys

The Zn-Mg alloys with Mg additions of 35%, 40% and 45%（mass fraction） were prepared by conventional casting method, with the aim to develop new biodegradable materials. The effects of cooling rate and composition on the microstructures, hardness and corrosion resistance were studied by XRD, SEM, microhardness and corrosion testing techniques. The corrosion behaviors of experimental alloys in simulated body fluids were analyzed. The results show that the amount of the petal-like MgZn2 phase decreases, as well as the hardness of the alloys, but that of the polygonal MgZn2 phase increases with the increase of Mg content when the cooling rate is constant. When the alloy composition is constant, the MgZn2 phase changes easily from petal-like to polygon, and the hardness decreases with the decrease of the cooling rate.     

Effects of Sc and Mn on microstructures and mechanical properties of Mg-Gd alloy

Two alloys of Mg-12.4Gd and Mg-12.5Gd-0.8Sc-1.4Mn were prepared. Hot extrusion and T5 heat treatment were conducted, and then the mechanical properties of the two alloys were tested at room and high temperatures. The effects of Sc, Mn on the microstructures of Mg-12.4Gd were investigated by optical microscopy, scanning electron microscopy and transmission electron microscopy. The results demonstrate that after hot-extrusion the alloying with Sc, Mn can efficaciously refine the grains of Mg-12.4Gd alloy; and increase the elongation at room and high temperatures after T5 heat treatment. But the strength at high temperature is not obviously improved.     

Effect of mischmetal and yttrium on microstructures and mechanical properties of Mg-Al alloy

The effect of yttrium and mischmetal(MMs)on the as-cast and solid solution treated structures of Mg-Al alloys with different Al-contents was investigated.The results show that the MMs in Mg-Al alloy existed in rod Al4(Ce,La)compound while Y in Mg-Al alloy in polygonal Al2Y compound.The amount of Mg17Al12 in Mg-Al alloy is decreased with increasing Y or MMs addition,and Mg17 Al12 intermetallic compound is changed from continuous network to discontinuous one.The Al4(Ce,La)and Al2Y compounds are not dissolved into Mg-Al alloy matrix during solid solution treatment so that their high heat stability can be exhibited.The experiment of mechanical properties indicate that elongation and impact toughness of the Mg-Al-Y alloy with polygonal Al2Y compound are higher than those of Mg-Al-MMs alloy with rod A4(Ce,La) compound.     

Effect and mechanism of diphosphonic acid on flotation characteristic of fersmite and intergrowth gangue

1　INTRODUCTIONThereservesofniobium containingmineralsinChinatakethesecondplaceintheworld ,anddis tributemainlyinBaiyuneboofInnerMongolia ,TaimeiofGuangdongProvinceandYichunofJiangxiProvince ,etc .Niobium containingmineralsweredis coveredover 130kinds ,butonlyafewofthemhadindustrialvalue .Fersmiteisoneoftheseveralvaluedindustrialniobium containingminerals[1,2 ] .Theprocessingofniobium containingmineralsistoodifficultduetotheirfinesizeandnumerousspeciesandcomplexcomposing .Inmiddleperi…     

Effect of Mn and MnS on corrosion properties of domestic pipeline steels and welds

Base metals of domestic pipeline steels were used to study the effect of Mn on corrosion properties of SSCC( Sulfide Stress Corrosion Cracking), and welds were carried out to study the effect of MnS on corrosion properties of HIC ( Hydrogen Induced Cracking) both in solutions with wet hydrogen sulfide ( H2 S ). They were respectively conducted by referring to the standards of SSCC and HIC. Testing results revealed that with the increase of content Mn, the resistance of SSCC will be decreased, from the point of metallurgic view, and it is Mn element not C element to lead to the testing results of SSCC. Meanwhile, even under the condition without inclusions MnS, HIC in welds still occurred. That is to say, MnS is not necessary for HIC, the presence of local banded structures in which Mn and P are inclined to aggregate cause to the phenomena of HIC.     

Microstructures and properties of welded joint of TiNi shape memory alloy and stainless steel

The fracture characteristics of the joint were analyzed by means of scanning electron microscope(SEM).Microstructures of the joint were examined by means of optical microscope, SEM and an image analyzer. The results show that the tensile strength of the inhomogeneous joint of TiNi shape memory alloy and stainless steel is lower than that of the homogeneous joint and a plastic field appears in the heat affected zone on the side of TiNi shape memory alloy. Because TiNi shape memory alloy and stainless steel melted, a brittle as-cast structure was formed in the weld. The tensile strength and the shape memory effect of the inhomogeneous joint are strongly influenced by the changes of composition and structure of the joint. Measures should be taken to reduce the base metal melting and prevent the weld metal from the invasion by O for improving the properties of the TiNi shape memory alloy and stainless steel inhomogeneous joint.     

Effect of rolling and heat treatment on microstructure and properties of Ti-26 sheet

The effect of heat treatment and rolling process on the properties and microstructures of Ti-26 （Ti-15V-3Al-3Cr-3Sn-Forming） sheet was studied. The results show that the best rolling temperature for Ti-26 alloy is in the temperature range from 900 ℃ to 950℃. Under this condition, the resistance of deformation and yield ratio are low and the alloy has better hot work ability. The alloy will achieve better mechanical properties and completely recrystallized β microstructure when the deformation ratio is not less than 60% and the solution temperature is 30 ℃ above the phase transformation temperature. The best heat treatment conditions are recommended as： 790℃, 30 min, AC or WQ followed by 510 ℃, 10 h, AC. Under this heat treatment condition the strength of the Ti-26 alloy is 1 230 MPa and the elongation is 15%.     

Mechanism and control of un-straightness of EMC large slabs

1　INTRODUCTIONLargealuminumslabsareusually producedinsuchelectromagneticcasting (EMC ) ,asshowninFig .1.TherollingfacesorbroadfacesoftheEMClargeslabstendtoform pull indefectduringcastingprocess,whichdirectlyinfluencesthequalityoftherollingfaces .Becauseofthisdefect,theexpenseofscalingtherollingfaceshastobeadded ,besides ,thehighqualitysurfacemetalhastobescaled ,thequali tyofslabsisdecreasedgreatly .Sotoobtainoriginalslabswithstraightrollingfaceswhichcanberolleddirectlyisasignificantta…