雙相復合負溫度系數(shù)熱敏材料的電性能研究.pdf

1、中國科學技術大學碩士學位論文雙相復合負溫度系數(shù)熱敏材料的電性能研究姓名：羅偉申請學位級別：碩士專業(yè)：材料學指導教師：楊萍華陳初升20090501AbstractAbstractSomematerialsexhibitdecreasingelectricalresistancewithincreasingtemperatureThermistorsmadefromthesenegativetemperaturecoefficient(NT

2、0materialshavebeenwidelyusedfortemperaturemeasurementandcontrol，andforthesuppressionofinrushcurrent，duetotheirhighsensitivitytotemperaturechange，highstabilityandlowpriceMostofNTCthermistorsarebasedonmixedoxidesoftransiti

3、onalelements(Mn，Ni，F(xiàn)e，Co，Cu)andtherareearthelementswhichcrystallizeinspinelstructure，perovskitestructureandfluoritestructureTheirspecificresistivityfollowsthewellknownArrheniusrelation：p=poexp(Ea／kT)，inwhichPisthespecifi

4、cresistivity，P0theresistivityatinfinitetemperature，Eatheactivationenergyforelectronicconduction，kBoltzmarm’SconstantandTabsolutetemperatureTwoparametersareusedtocharacterizeNTCthermistormaterials，P25，thespecificresistivi

5、tyat250CandthethermalconstantB(unitinK)withB=EJkForpracticalapplications，akindofNTCthermistorswithhighelectricalresistivityandlowBvalueaswellashighstabilityarerequiredHowever，thiskindofNTCmaterialWashardtobepreparedfromt

6、heregularNTCmaterialThisstudyistopreparethiskindofNTCmaterialbyintroducingtheinsultingYSZtotheconductivespineltoformacompositeInChapterlgivesabriefintroductiontothehistory，basicparameters，applicationanddevelopmenttrendof

7、NTCceramicsStudiesonthepreparationmethodsandtheconductionmechanismoftheceramicsarereviewedaswellFinally，theoutlineofthisdissertationisdescribedInChapter2，amodifiedsolidstatereactionmethodhasbeenadoptedtoprepareFeosCuo2Ni

8、o66Mnl64powderThenitwasmechanicallymixedwith8YSZpowder(FucideHefeiChina)andsinteredat1200“(2TheeffectsofYSZontheelectricalproperties，microstructure，phasecompositions，stabilityandNTCcharacteristicofseriesFeo5Cuo2Nio66Mnl6

9、4／YSZcompositesareinvestigatedItWasfoundthattheelectricalconductionofthecompositeCallbedescribedquantitativelyusingthepercolationtheoryThisworkshowsthattheintroductionofYSZintothespineloxideFeo5Cuo2Nio66Mnl6404resultinal