Thermal Analysis: methods, principles, applicaon

[Pages:48]ThermalAnalysis:methods,principles,applica5on

AndreyTarasov LectureonThermalanalysis

26.16.2012

Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12

Main definitions Heat

Heat Capacity C=Q/T, [J/mol/K]

Thermal conductivity =a?Cp? =[J/s/m/K]=[W/m/K]

a ? thermal diffusivity, m2/s

Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12

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Defini5onofTA Groupofphysical-chemicalmethodswhichdealwithstudyingmaterials and processes under condi5ons of programmed changing's of the surroundingtemperature.

Differential Heat equation

Main Thermo-physical properties of materials

Property/Characteris5c

Mathema5cal expression

Unit

Thermalconduc5vity

Thermallinear expansion

(T)=a?Cp(T)?(T) =1/r*(dr/dT)

W/(m*K) %/K

Enthalpy

dQ/dt=m?Cp?(dT/dt)

J/g

Weight/Composi5on/ Conversion

=(mo-mi)/mo

%

Method

LFA DIL DSC TG

r, - polar coordinates z - applicate ? Thermal conductivity , J/(cm*s*K) Cp ? Thermal capacity, J/(g*K) ? density, g/(cm3) Q ? heat of the process (reaction) ? degree of conversion

a ? thermal diffusivity, cm2/s

Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12

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Thermal conductivity, thermal diffusivity

Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12

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Laser Flash Method (LFA)

(T)=a?Cp(T)?(T)

Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12

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Dilatometry (DIL)

=1/r*(dr/dT)

? thermal expansion coefficient r ? sample length

DIL Measurement Information ?Linear thermal expansion ?Determination of coefficient of thermal expansion ?Sintering temperatures ?Softening points ?Phase transitions

SiN thermal shrinkage

Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12

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Basic Principles and Terminology

Principleofcombinedthermocouple Registra5onthetemperatureoftheobjectandtemperaturedifference betweensampleandreference

Consequence Dependingontheengineeringdesign,measuringcellconstruc5onandtheway ofdatarepresenta5on,varietyofmethodshasbeenarisen:DTG,DTA,DSC,STA etc.

Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12

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Basic Principles and Terminology

DSC-TG

DSC-(Differen5alScanningCalorimetry): VoltagetokeepT=TS-TR=0vs.T RDTA(ReverseDifferen5alThermalAnalysis) TG dt/dTvs.T

InAC ThermoLab

Calvet TA

TA?(Thermalanalysis) TSvs.t TG?(Thermogravimetricanalysis) mvs.T DTA-(Differen5alThermalAnalysis) T=TS-TRvs.T

DDTA-(Deriva5veDTA) dT/dtvs.T

DTA-TG Calvet-DSC

STA?SimultaneousThermalAnalysis:TG?DSC;EVA?Evolvedgasanalysis:MS,FTIR,GC

Hyphenated techniques

Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12

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