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简介：Uniformdiamondfilmsarehighlydesirableforcuttingindustries,duetotheirhighperformanceandlonglifetimeusedoncuttingtools.Nevertheless,theyaredifficulttoobtainoncuttingtoolswithcomplicatedshapes,greatlylimitingtheapplicationsofdiamondfilms.Inthisstudy,anovelapproachofdepositionforuniformdiamondfilmsisproposed,oncircularsawbladesmadeofcementedcarbideusingreflectorsofbrasssheets.Diamondfilmsaredepositedusinghotfilamentchemicalvapordeposition(HFCVD).Anovelconcavestructureofbrasssheetsisdesignedandfabricated,improvingthedistributionoftemperaturefield,andovercomingthedisadvantagesoftheconventionalHFCVDsystems.ThisincreasestheenergyefficiencyofusewithoutchangingthestructureandincreasingthecostofHFCVD.Thegrainsarerefinedandtheintensitiesofdiamondpeaksarestrengthenedobviously,whichisconfirmedbyscanningelectronmicroscopyandRamanspectrarespectively.

简介：DedicatedexperimentsintheHT-7tokamakwereperformedtoinvestigatethein-fluenceoferosionanddepositiononthemirrorsamples.Thefirstmirror(FM)samplesmadeofpolycrystalline(PC)stainlesssteel(SS),molybdenum(Mo)andtungsten(W)werefixedonaholderatanangleof45withrespecttothehorizontalplaneandsetatdifferentlocationswithdifferentconnectionlengthsalongthemagneticfield.Theopticalreflectivityofthefirstmirrorwasmeasuredbyaspectrophotometerbeforeandafterplasmaexposure.Itwasfoundthatthesurfacemorphologyandspecularreflectivityofthemirrorsamplesaftertheexposureweredifferentwithrespecttothedifferentdistancesfromthemirrorsurfacetothelastclosedfluxsurface(LCFS)oftheplasmainthetokamak.Itwasalsofoundthatshorteningtheconnectionlengthbeforethemirrorsurfacewouldweakentheinfluenceoftheplasmaerosionandimpuritydepositiononthemirrorsurface.Inordertomaintaintheopticalcharacteristicsofthemirrorsurface,itisnecessarytoadoptthein-situcleaningandmirrorprotectiontechniques.

简介：Inthisstudy,SiO_xfilmsweredepositedbyadielectricbarrierdischarge(DBD)plasmagunatanatmosphericpressure.TherelationshipofthefilmstructureswithplasmapowerswasinvestigatedbyFouriertransforminfraredspectroscopy(FTIR),andscanningelectronmicroscope(SEM).Itwasshownthatanuniformandcross-linkingstructurefilmwasformedbytheDBDgun.Asanapplication,theSiO_xfilmsweredepositedonacarbonsteelsurfacefortheanti-corrosionpurpose.Theexperimentwascarriedoutina0.1MNaC1solution.Itwasfoundthataverygoodanti-corrosivepropertywasobtained,i.e.,thecorrosionratewasdecreasedc.a.15timesin5%NaClsolutioncomparedtothenon-SiO_xcoatedsteel,asdetectedbythepotentiodynamicpolarizationmeasurement.

简介：TiBCNnanocompositecoatingsweredepositedoncementedcarbideandSi（100）byacathodearcplasmasystem,inwhichTiB2cathodeswereusedinmixturegasesofN2andC2H2.X-raydiffractionshowsthatTiB2andTi2B5peaksenhanceatlowflowratesofC2H2,buttheyshrinkwhentheflowrateisover200seem.AnincreaseofdepositionratewasobtainedfromdifferentTiBCNthicknessesforthesamedepositiontimemeasuredbyscanningelectronmicroscopy.Atomicforcemicroscopyshowsthatthesurfaceroughnessesare10nmand20nmatC2H2flowratesof0-100sccmandof150-300sccm,respectively.HighresolutiontransmissionelectronmicroscopyandX-rayphotoelectronspectroscopyshowthatthecoatingsconsistofnanocrystalphasesTi2B5,TiB2andTiN,andamorphousphasecarbonandBN.Theaveragecrystalsizesembeddedintheamorphousmatricesare200nmand10nmatC2H2flowratesof200sccmand300sccm,respectively.InRamanspectra,theD-andG-bandsincreasewithC2H2flowsatlowflowrates,butweakenathighflowrates.Themicrohardnessofthecoatingsdecreasesfrom28.6GPato20GPaastheC2H2increasesfrom0sccmto300sccm,andtheball-on-diskmeasurementshowsadramaticdecreaseofthefrictioncoefficientfrom0.84to0.13.ThereasonforthereducedhardnessandfrictioncoefficientwiththechangeofC2H2flowratesisdiscussed.

简介：Thecharacteristicsofhomogeneousdischargesinmixedgasesofhydrogendilutedsilaneandargonatatmosphericpressureareinvestigatednumericallybasedonaone-dimensionalfluidmodel.Thismodeltakesintoaccounttheprimaryprocessesexcitationandionization,sixteenreactionsofradicalswithradicalsinsilane/hydrogen/argondischargesandtherefore,canadequatelyrepresentthedischargeplasma.Weanalyzetheeffectsofveryhighfrequency(VHF)onthedensitiesofspecies(e,H,SiH3,SiH+3andSiH2)insuchdischargesusingthemodel.ThesimulationresultsshowthatthedensitiesofSiH3,SiH+3,H,andSiH2increasewithVHFwhentheVHFrangesfrom30MHzto150MHz.Itisfoundthatthedepositionrateofμc-Si:HfilmdependsontheconcentrationofSiH3,SiH+3,SiH2,andHintheplasma.TheeffectsofVHFonthedepositionrateandtheamountofcrystallizedfractionforμc-Si:Hfilmgrowthisalsodiscussedinthispaper.

简介：Influenceoftheparametersofplasmaenhancedchemicalvapordeposition(PECVD)onthesurfacemorphologyofhydrogenatedamorphoussilicon(α-Si:H)filmwasinvestigated.Theroot-mean-square(RMS)roughnessofthefilmwasmeasuredbyatomicforcemicroscope(AFM)andtherelevantresultswereanalyzedusingthesurfacesmoothingmechanismoffilmdeposition.Itisshownthatanα-Si:HfilmwithsmoothsurfacemorphologycanbeobtainedbyincreasingthePH_3/N_2gasflow-ratefor10%inahighfrequency(HF)mode.Forhighpower,however,thesurfacemorphologyofthefilmwilldeterioratewhentheSiH_4gasflowrateincreases.Furthermore,optimizedparametersofPECVDforgrowingthefilmwithsmoothsurfacewereobtainedtobeSiH_4:25sccm(standardcubiccentimetersperminute),Ar:275sccm,10%PH_3/N_2:2sccm,HFpower:15W,pressure:0.9Torrandtemperature:350℃.Inaddition,forinthickfilmdepositiononsiliconsubstrate,aN_2OandNH_3preprocessingmethodisproposedtosuppresstheformationofgasbubbles.

简介：Depositionofnanocrystallinesilicon(nc-Si)onglassatverylowtemperaturesbyelectroncyclotronresonance(ECR)plasmaenhancedchemicalvapourdeposition(PECVD)wasinvestigated.Itwasshownthatnc-Sicouldbedepositedfromhydrogendilutedsilanegasatasubstratetemperatureof80℃withacrystallinefractionupto80%andalateralgrainsizeofaround50nm.Thiswasachievedbygrowingthenc-Siinalowpressureregimewhichensuredthatmono-silylspecieswerethedominantdepositionprecursor.Furthermore,ahighfluxofenergetichydrogenionswasrequiredtoinducecrystallisationofthesiliconmaterialthroughachemicalannealingprocess.

简介：AlONnanolayersaresynthesizedonAlsubstratebytheirradiationofenergeticnitrogenionsusingplasmafocusing.Samplesareexposedtomultiple(5,10,15,20and25)focusshots.Ionenergyandionnumberdensityrangefrom80keVto1.4MeVand5.6×1019m-3to1.3×1019m-3,respectively.Moreover,theefectofcontinuousannealing(473Kand523K)onanAlNsurfacelayersynthesizedwith25focusshotsisalsoexamined.ThemainfeaturesoftheX-raydifraction(XRD)patternswithincreasingfocusshotsare:(i)variationinthecrystallinityofAlNalong(111),(200)and(311)planes,(ii)increasingaveragecrystallitesizeofAlN(111)plane,and(iii)stressrelaxationobservedinAlN(111)and(200)planes.ThecrystallinityofAlNsurfacelayeriscomparativelybetterat473Kannealingtemperature.Abroadeneddifractionpeakrelatedtoanaluminiumoxidephaseshowingweakcrystallinityisobservedfor15focusshotswhilenon-boundedoxidesarepresentinallotherdepositedlayers.RamanandFouriertransforminfraredspectroscopy(FTIR)analysisconfirmthepresenceofAlNandAl2O3forthesurfacelayerannealedat473Ktemperature.RamananalysisshowsthattheoverlappingofAlNandAl2O3resultsinthedevelopmentofresidualstresses.Scanningelectronmicroscope(SEM)resultsdemonstratethattheformationofroundedgrains(rangefrom20nmto200nm)andvariationsintheirmicrostructuresfeaturesdependontheincreasingnumberoffocusshots.Decompositionoflargerclustersintosmalleronesisobserved.