简介:Thecombinedquadraticorthogonalregressionmethodofexperimentdesignwasemployedtoexploretheeffectsofprocessparametersofplasmanitridingoftantalumsuchastotalpressure,temperatureandoriginalhydrogenmolarfractiononthehardness,roughnessandstructureofnitridingsurfaces.Theregressionequationsofhardness,roughnessandstructureweregivenaccordingtotheresultsofregressionandstatisticanalysis.Andthediffusionactivationenergyofnitrogenintantalumonplasmanitridingconditionswascalculatedaccordingtotheexperimentaldataofhardnessofplasma-nitridingoftantalumvstimeandtemperature.Thediffusionactivationenergycalculatedbelongsto(155.49+10.51)kJ/mol(783-983K).
简介:Titaniumandtitaniumalloyshaveseveraladvantages,butthecostoftitaniumalloysisveryexpensivecomparedwiththetraditionalmetalmaterials.Thisarticleintroducestwonewlow-costtitaniumalloysTi-2.1Cr-1.3Fe(TCFalloy)andTi-3Al-2.1Cr-1.3Fe(TACFalloy).Inthisstudy,weusedCr-Femasteralloyasoneoftherawmaterialstodevelopthetwonewalloys.Weintroducethemicrostructureandtensilepropertiesofthetwonewalloysfromβsolutiontreatedwithdifferentcoolingmethods.Optica...
简介:Thechloridizingsegregationandmagneticseparationoflow-gradenickellateritesfromYunnanprovinceofChinawasinvestigated.Thenickellateriteswerecharacterizedbymicroscopicinvestigations,usingX-raydiffractometry(XRD)andenergydispersivespectrometry(EDS)techniques.Thepellets,whichwerepreparedwithmagnesiumchlorideandcokeaschlorideagentandreductantrespectively,wereheatedtoahightemperature,andthepelletsaftercoolingwerecrushedformagneticseparation.Aseriesofexperimentswereconductedtoexaminetheeffectofchlorinatingagentdosage,reductantdosage,chloridizingtemperatureandchloridizingtimeonenrichmentgradeofNiandCo.TheresultsindicatethatthefourfactorshavesignificanteffectsontheextractionsofNiandCo.Theoptimumconditionsareasfollows:theamountsofmagnesiumchlorideandcokeare6%and2%,respectively,chloridizingtemperatureis1253K,andchloridizingtimeis90min.Undertheconditions,extractionsofNiandCoreach91.5%and82.3%,respectively.
简介:Aprocessoftheselectiveleachingofnickelfromlow-sulfurNi-Cumatteatatmosphericpressurewasdescribed.ThismattewasobtainedfromhighgradeNi-Cumattebymagneticseparation,whichmainlycontainedNi-Cualloyandasmallquantityofsulfides.Firstly,theacid-oxygen(CuSO4-H2SO4-O2)leachingofthemattewasconductedatatmosphericpressure.WhenthesolutionpHvaluereached1.0-2.0,theoxygenflowwasceased.Then,theaqueouscopperwasrejectedbycementationreactionwithNiinthealloy.ThemineralogicalcharacteristicsofthematteintheprocesswereanalyzedbyX-raydiffractometry,opticalmicroscopyandscanningelectronmicroscopy.Andtheeffectsofvariationsintemperature,particlesizedistribution,oxygenflowrate,pulpdensity,initialacidconcentrationandinitialconcentrationofcopperionwereinvestigated.
简介:Theout-of-planedeformationisaseriousprobleminthin-plateweldedjoint,anditisdifficulttoreduceorcontrolthedistortionduringweldingprocess.Externalrestraintisregardedasaneffectivemethodtomitigatethedistortion,anditiswidelyusedintheactualmanufacturingprocess.Inordertoinvestigatetheinfluenceofexternalrestraintonweldingdeformationinthinplatejoints,athermo-elastic-plasticfiniteelementmethodbasedonABAQUSsoftwarewasdevelopedtocalculatewelding-induceddeformation.Meanwhile,weldingdeformationinthethin-platejointswasmeasuredbyexperiments.Throughcomparingthenumericalresultswiththemeasureddata,theeffectivenessofthedevelopedcomputationalapproachwasverified.Basedonthesimulatedandexperimentalresults,thegenerationmechanismoftheout-of-planedeformationinthinplatebead-onjointwasdiscussed,andtheinfluenceofexternalrestraintonthefinalweldingdeformationwasclarified.
简介:AnewtypeofDZ9000EOxygenGaseousHVOFsystem(GHVOF)isdevelopedwhichcanreducethecostofcoatingsandincreasethein-situremovabilitytoadaptvariousworkingconditions.Thewholesystemiseconomical,whichenablesthesystemtomeettherequirementofsprayingmediumorlowcostHighVelocityOxy-Fuel(HVOF)coatingsformediumandsmalljobshops.ThedepositedcermetscoatingsbytheDZ9000EsystemhavegoodperformancewithaveragemicrohardnessHV0.2ofmorethan1000andthebondstrengthbetweencoatingandsubstrateofgreaterthan50MPa.