偏钒酸铵和纳米碳黑为原料制备纳米碳化钒

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1、毕业设计（论文）摘要本文以偏钒酸铵和纳米碳黑为原料，先将原料制成前驱体粉末，再在真空碳管炉中进行碳热还原反应，在一定条件下制备纳米碳化钒粉体。偏钒酸铵在150℃左右分解为五氧化二钒、氨气和水，使碳和钒氧化物得到充分混合，因而扩散距离缩短，碳化温度降低，反应时间缩短，晶粒尺寸得到有效控制。主要采用了XRD、SEM等分析手段研究了不同工艺条件（反应温度、保温时间、配碳量）对制备纳米碳化钒的影响，通过研究得到以下主要结论。以纳米碳黑和偏钒酸铵为原料可在1100℃时制备相成分单一的V8C7粉体，粉末颗粒的形貌较规则，粉末粒度较小，呈球形或类球形，粉末颗粒的平均粒度小于100nm。当

2、保温时间达到或接近最佳值（本实验为60min）时，反应才能进行彻底，颗粒的形貌较规则，且形貌细小。当碳含量为28%时，主相为V8C7，不含其它杂质相，并且晶格常数最接近理论值。关键词：碳化钒碳热还原法偏钒酸铵I毕业设计（论文）TitleStudyonPreparationofNanometerVCPowderAbstractThispaperdealswithanewmethodtopreparenanometervanadiumcarbidepowderundercertainconditions.TherawmaterialsincludingNH4VO3andnano

3、metercarbonweremadeintotheprecursorpowderfirst.Thecarbothermalreductionhappenedinthevacuumcarbontubefurnace.NH4VO3isdecomposedintoV2O5NH3andH2Oabout150℃,sothecarbonandvanadiumoxidesarefullymixed,andthusreducethediffusiondistance,carbonizationtemperaturedecreases,shorterreactiontimethegrain

4、sizehasbeeneffectivelycontrolled.Theeffectsofprocessconditions(reactiontemperature,keepingtimeandproportioningratioofthecarbonpowder)wereinvestigatedbyX-raydiffractionandscanningelectronmicroscope(SEM).Theresultsarelistedasfollows:UsingNH4VO3asrawmaterials,V8C7powderofsinglephasecanbeobtai

5、nedat1100℃.Themorphologyofthepowderisratherorderandspheroidorsimilartospheroid.Theparticlesizeislessthan100nm.Whentheholdingtimeatorclosetotheoptimumvalue(inthisexperiment60min),thereactioncanbecarriedoutthoroughly,moreregularparticleshape,andmorphologyofsmall.Whenthecarboncontentwas28%,th

6、emainphaseV8C7,withoutotherimpurityphase,andthelatticeconstantoftheclosesttheoreticalvalue.Keywords:VanadiumCarbideCarbothermalReductionNH4VO3II毕业设计（论文）目次1绪论............................................................................................................................11.1碳化钒的性

7、质及用途.......................................................................................11.1.1钒简介....................................................................................................11.1.2钒的化合物.................................................