Scannig-Electronic-Microscop扫描电子显微镜原理

ScanningElectronicMicroscope•Scanningelectronicmicroscope(SEM)isaninstrumentusedtomagnifythefinedetailsofmaterialsurfacessuchaspolymersplitting,polymerpull-out,debonding,matrixcrackingandpolymermatrixadhesionanddetermineitschemicalcomposition.•Itisalsousedtocheckthemorphology,andcrystallizationstructure.Scanningelectronicmicroscopyconsistsof:•Electrongun•Condenserlens•Scancoil•Objectivelens•SpecimenanddetectorPrincipleofSEM•Abeamofelectronsisproducedatthetopofthemicroscopebyanelectrongun.•Theelectronbeamheldwithinavacuumanddirectedtothesamplethroughelectromagneticfieldsandlenses.•Oncethebeamhitsthesample,electronsandX-raysareejectedfromthesample.•DetectorscollectX-rays,backscatteredelectrons,andsecondaryelectronsandconvertthemintoasignal.Thiswillproducethefinalimage.Samplepreparation1.Degreasesampleusingacetone-toensureremovalofhydrocarbonandvolatilecompound.2.Sampleneedtobedehydratedtomakesurenowaterpresentinthesample.-Dryingintheovenat60⁰Cfor24hours.3.Nonconductivesampleneedtobeconvertedbycoatingthesamplethinlayerofconductivematerial(e.g.gold)particleusingsputtercoaterForPLA,systemoperatedat20to30KVandthephotowasrecordedat1000-3000xmagnification