热重分析(TGA)-完整版资料.pdf

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1、热重分析(TGA)Theory&Applications120612.57%Water(0.8753mg)19.47%CarbonMonoxide100(1.355mg)430.07%CarbonDioxide80(2.093mg)2Weight(%)60Deriv.Weight(%/min)04020-202004006008001000Temperature(°C)UniversalV3.4ATAInstrumentsTGA:TheTechniqueThermogravimetricAnalysis(TGA)measurestheamountandrateofchangeinthewei

2、ghtofamaterialasafunctionoftemperatureortimeinacontrolledatmosphere.•样品在热环境中发生化学变化、分解、成分改变时可能伴随着重量的变化。•热重分析就是在不同的热条件（以恒定速度升温或等温条件下延长时间）下对样品的质量变化加以测量的动态技术。热重分析的结果用热重曲线或微分热重曲线表示。2WhatTGACanTellYou•ThermalStabilityofMaterials热稳定性•OxidativeStabilityofMaterials氧化稳定性•CompositionofMulti-componentSystems组成

3、•EstimatedLifetimeofaProduct产品寿命•DecompositionKineticsofMaterials分解动力学•TheEffectofReactiveorCorrosiveAtmospheresonMaterials反应或腐蚀气氛对材料的影响•MoistureandVolatilesContentofMaterials材料水分和挥发份含量3MechanismsofWeightChangeinTGA
WeightLoss:
Decomposition:Thebreakingapartofchemicalbonds.
Evaporation:Thelossofvol

4、atileswithelevatedtemperature.
Reduction:Interactionofsampletoareducingatmosphere(hydrogen,ammonia,etc).
Desorption.
WeightGain:
Oxidation:Interactionofthesamplewithanoxidizingatmosphere.
Absorption.Allofthesearekineticprocesses(i.e.thereisarateatwhichtheyoccur).4TG曲线积分型曲线DTG曲线微分型曲线5初始热分解最大失重反应终了温温

5、度(B、G)速率温度度(C、H)6影响热重测定的因素:PurgeGas•TGA:Alwayspurgethroughbalancehousingwithdryinertgas•TGA:Onlyintroducereactive/corrosivegasesthroughsamplearea/furnacehousing•Nitrogenmostcommon.•Heliumoftenprovidesbestbaselinebutwillmakefurnaceworkhardathightemperature.•Aircansometimesimproveresolutionbecauseofd

6、ifferencesintheoxidativestability(versusthermalstability)ofcomponents.气氛不同反应机理的不同。7TGA:PurgeGasFlow40ml/min10ml/min90ml/min60ml/minEGAFurnaceStandardFurnace8TestforOxygenContaminationofNPurgeGas21203CopperOxalate320.79°C+1002C)°801Weight(%)6010minuteN2pre-purge0[------------]Deriv.Weight(%/40-10100

7、200300400500600Temperature(°C)9EffectofOxygenonCopperOxalateDecomposition464544HighOxygen43Weight(%)MediumOxygen42LowOxygen41300350400450500550600Temperature(°C)10TGA:BaselineConsiderations•Goodwaytoquantif