一種單晶高溫合金NiCrAlY-ZrO-,2-熱障涂層的氧化行為.pdf

1、湖南大學(xué)碩士學(xué)位論文一種單晶高溫合金NiCrAlYZrO熱障涂層的氧化行為姓名：李美姮申請學(xué)位級別：碩士專業(yè)：材料物理與化學(xué)指導(dǎo)教師：胡望宇管恒榮2000.12.1摘要ABSTRACTInthispaperabondcoat(Ni一30Cr一12AI一03Y(、vt％))hadbeendepositedonaNi—basesinglecrystalsuperalloybymagnetronsputtering，andthenatopco

2、at(7wt％Y203Zr02)hadbeendepositedbyelectronbeam—physicalvapordeposition(EBPVD)Themicrostructuresandhi曲temperatureoxidationbehaviorofsputteredNiCrAIYcoating，theeffectofvacuumheattreatmentonoxidationbehaviorofsputteredNiCrA

3、lYcoating，andthehi曲temperatureoxidationbehaviorofEB—PVDTBCshadbeeninvestigatedbyusingthermogravimetryanalysis(TGA)，xraydiffraction(XRD)，scanningelectronmicroscopy(SEM)，andtransmissionelectronmicroscopy(TEM)Themainresults

4、aresummarizeda8following：TheoxidescalesformedonsputteredNiCrAIYcoatingsafteroxidationat900，1000，and1100℃consistedofonlyA1203麗tllexcellentadhesionDuringtheoxidation，ae_a—A1203phasetransformationhappened，andthehighertheoxi

5、dationtemperature，thefasterthephasetransformation111eformationprocessofa—A1203onNiCrAIYcoatingwouldbeacceleratedandpromotedbyvacuumheattreatment，andtheformed旺一A1203scalehadabetteradherencetotheNiCrAlYcoatingConsequentlyt

6、heoxidationresistanceofsputteredNiCrAlYcoatingWaSimprovedsignificantlybyvacuumheattreatmentDuringhightemperatureoxidationofTBCs，thenon—equilibriumtetragonalphase(t，)decomposedgraduallytoequilibriumtetragonal(t)andcubic(c

7、)phaseAfter300thermalcyclesat1050“C，itwasobservedthatsmallamountsofmonoclinicphasewastransformedfromtetragonalphaseBythemicrostructureobservation，EDXandⅪ①analysis，it懈foundthatmicro—cracksimtiatedpreferablyintheYPSZtopcoa

8、talongcolumnargrainboundaries，andthenpropagatedthroughthewholetopcoatdowntotheTGOlayersConsequentlyoxygentransportationWaSacceleratedandcausedseverinternaloxidationinthebondcoatWiththeincreasingofthermalcycles，AIWasdeple