流延法制备氧化钨基功能材料电学性能的研究

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1、西南交通大学硕士学位论文流延法制备氧化钨基功能材料电学性能的研究姓名：张英申请学位级别：硕士专业：凝聚态物理指导教师：王豫20080501AbstractAsakindoftransitionmetaloxide，becauseofitsmultiphaseandferroelectricity，W03(tungstentrioxide)havemanyspecialproperties·AsanimportantsemiconductormaterialW03isextensivelyusedinfuelcel

2、ls，electrochromicdevice，photocatalyticdegradation，toxicgassensorandothers-Inrecentyears,someauthorsreportedstudiesonnonohmicbehaviorofsinteredW03ceramicsindicatingW03-basedceramicsarepotentialvaristormaterials·However，theelectricalpropertiesofsinteredW03ceram

3、icsareinstable，whichISanobviousobstacleforpracticalapplicationofW03asavaristormaterial．InthisWOrk，singlecomponenandfunctionallygradientmaterials(FGM)ispreparedbythemethodoftapecasting，anditselectricalproperties(current-voltagecharacteristic，resistivity，impeda

4、nce)、internalrelationswerediscussed．Theprincipalresearchcontentsinclude：Thepreparationoftapecastingslurryisexplored，throughtesttodecidetheoptimizedtechnologycondition．Thefreecrackssampleswerefabricated．Themicrostructuresofsampleswereobservedbyusingascanningel

5、ectronmicroscope．Basedonthestudyofthecurrent·voltagecharacteristics，wefindoutthatboththesinglecomponenandfunctionallygradientmaterialsofC0203dopedW01behavednegativedifferentialresistance(NDR)characteristic．However，theNDRappearsinnonlinearregionandthepropertyi

6、scorrelatedwiththeelectrichistoryofthesamples．Forfunctionallygradientmaterials，Nodelaminationwasobservedinanycaseafterhightemperaturesintering．Moreover；wealsoObseI、，edthattheelectricpropertyofFGMexhibitedanisotropy．Thepropertydif．ferentfromtraditionalmaterial

7、soriginatesfromheterogeneityofcomposition，anditisnotdeterminedbysomelayerofthesample．Wo．97．xCoo．03A1x03polycrystallineceramicbulkswerefabricatedbyconventionalceramictechnique．WefoundthattheproperamountsofA1203canreducetheresistivityofceramicsandimprovetheelec

8、tricalstabilityofceramics．Inaddition，thecontentofA1203canadjusttheresistivityandresistance．temperaturepropertiesofceramicsefficiently．ThisworksystematicallyinvestigatedtheFe203dopedW03sin