Thermal Analysis: methods, principles, applicaion

of 48/48
Thermal Analysis: methods, principles, applica5on Andrey Tarasov Lecture on Thermal analysis 26.16.2012 Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12
  • date post

    11-Dec-2016
  • Category

    Documents

  • view

    243
  • download

    8

Embed Size (px)

Transcript of Thermal Analysis: methods, principles, applicaion

  • ThermalAnalysis:methods,principles,applica5on

    AndreyTarasovLectureonThermalanalysis

    26.16.2012Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12

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

    Main definitions

    Heat Capacity

    Heat

    Thermal conductivity

    =aCp =[J/s/m/K]=[W/m/K]

    a thermal diffusivity, m2/s

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

    2

  • Defini5onofTAGroupofphysicalchemicalmethodswhichdealwithstudyingmaterialsand processes under condi5ons of programmed changing's of thesurroundingtemperature.

    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

    Differential Heat equation

    Main Thermo-physical properties of materials

    Property/Characteris5cMathema5calexpression Unit Method

    Thermalconduc5vity (T)=aCp(T)(T) W/(m*K) LFA

    Thermallinearexpansion

    =1/r*(dr/dT) %/K DIL

    Enthalpy dQ/dt=mCp(dT/dt) J/g DSC

    Weight/Composi5on/Conversion

    =(mo-mi)/mo % TG

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

    a thermal diffusivity, cm2/s

    3

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

    Thermal conductivity, thermal diffusivity

    4

  • Laser Flash Method (LFA)

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

    (T)=aCp(T)(T)

    5

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

    Dilatometry (DIL)

    DIL Measurement Information

    Linear thermal expansion Determination of coefficient of thermal expansion Sintering temperatures Softening points Phase transitions

    =1/r*(dr/dT)

    SiN thermal shrinkage

    thermal expansion coefficient r sample length

    5

  • PrincipleofcombinedthermocoupleRegistra5onthetemperatureoftheobjectandtemperaturedifferencebetweensampleandreference

    ConsequenceDependingontheengineeringdesign,measuringcellconstruc5onandthewayofdatarepresenta5on,varietyofmethodshasbeenarisen:DTG,DTA,DSC,STAetc.

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

    Basic Principles and Terminology

    6

  • InACThermoLab

    TA(Thermalanalysis)TSvs.tTG(Thermogravimetricanalysis)mvs.T

    DSC(Differen5alScanningCalorimetry):VoltagetokeepT=TSTR=0vs.T

    DTA(Differen5alThermalAnalysis)T=TSTRvs.T

    DDTA(Deriva5veDTA)dT/dtvs.T

    RDTA(ReverseDifferen5alThermalAnalysis)dt/dTvs.T

    STASimultaneousThermalAnalysis:TGDSC;EVAEvolvedgasanalysis:MS,FTIR,GC

    Calvet TA

    Hyphenated techniques

    DSC-TG

    TG

    DTA-TG

    Basic Principles and Terminology

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

    Calvet-DSC

    7

  • Type Composi+on Temperaturerange,K Outputvoltage(0C),mVTmin Tmax

    T Cu/constantan 3 670 20

    J Fe/constantan 70 870 34

    E chromel/constantan 970 45

    K chromel/alumel 220 1270 41

    S Pt/PtRh(10) 270 1570 13

    R Pt/PtRh(13) 220 1570 12

    C W/WRe(26) 2670 39

    N Nicrosil/Nisil 1200 39Constantan - 58% Cu, 42% Ni

    Chromel 89% Ni, 10% Cr, 1%Fe

    Alumel 94% Ni, 2% Al, 1,5% Si, 2,5 % Mn

    Nicrosil/Nisil Ni, Cr, Silicon/Ni, Silicon

    CuNi disk sensor on Ag plate.

    Cu/Constantan disk sensor on Si(X) waffer.

    sensor sensor

    Pt-PtRh(10) diskshaped thermocouple

    Basic Principles and Terminology

    Thermocouples

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 8

  • TG DSC (Heat flux)

    STA SMP - Measurement signal FB - Buoyancy force , f(T) mA - Mass of adsorbed gas, f(T) mSC - Mass of sample container mS - Mass of sample , f(T) VA - Volume of adsorbed gas , f(T) VSC - Volume of sample container VS - Volume of sample, f(T)

    gas - Density of gas, f(T)

    SMP g = ((mSC + mS + mA) - (VSC + VS + VA) gas) g

    FB

    Basic Principles and Terminology

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 9

  • sensor sensor

    sample reference

    Basic Principles and Terminology

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 10

  • General Theory (Heat equation for inert material)

    b heating rate, K/min a -Temperature conductivity coefficient, cm2/s Thermal conductivity , J/(cm*s*K) Cp Thermal capacity, J/(g*K) density, g/(cm3)

    r, - polar coordinates

    Temperature lag

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 11

  • General Theory (Temperature field in active sample)

    Temperatureandreac5onextentfieldforendothermicprocess

    Temperatureandreac5onextentfieldforexothermicprocesses

    Exothermic Q>0, H

  • Pb(S) Pb(L), H298= 5 kJ/mol

    Setup baseline (zero line)

    Baseline interpolated

    Endothermic peak

    CuO(S)+H2(g) CuO(s)+H2O(g) , H298= -86 kJ/mol

    DSC TG

    Measurements may have a significant change in weight due to changes in gas density and viscosity.

    Shift of the baseline could appear due to change in thermal resistance of the setup. Position is depending on measuring-history.

    General Theory

    Blank measurement (zero line)

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 13

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

    Heat of the process is determined as follows:

    S availablesurfaceforheatexchangemsamplemassTgeneratedtemperaturedifference

    K(T) instrumentconstantradradia5onenergybetweenovenandsamples samplethermalconduc5vity

    General Theory

    A DSCpeakarea

    Heat balance (T) heattransfercoefficientc measuringcellheatcapacityMmassofthemeasuringcellTgeneratedtemperaturedifferencenormalizedconversion

    14

  • Standard Mel+ngPoint,C HeatofFusion,J/g

    In 156,6 28,6

    Sn 231,9 60,1

    Bi 271,4 53,1

    Pb 327,5 23,0

    Zn 419,5 107,5

    Al 660,0 397,0

    AlSi 577880

    Ag 961,8 104,6

    Au 1064,2

    Unalloeydsteels 11471536

    Ni 1455,0 290,4

    Pd 1554,8 157,3

    General Theory

    Calibration Standards

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 15

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

    1. ExperimentalDTAcurve2. DTAcurvecorrectedtoheattransfercondi5ons3. TruebaselineofDTAcurve4. Interpolatedbaseline;5. Experimentalbaseline;6. Experimentalbaselinealerprocess,shiledbecauseof

    thermalcapacitychanges.

    General Theory (DTA equation)

    hea/ngrate,K/min

    16

  • DSC Artifacts

    General Theory

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 17

  • General Theory

    Gradient T

    Baseline

    Calibration, KDTA,

    3 major aspects of correct DSC measurement:

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 18

  • General Theory

    Baseline definition.

    3 Tangential Area-Proportional Baseline This baseline is used when the melting process is accompanied by a notable Cp change and a sloping baseline exists.

    2 Sigmoidal Baseline This baseline is used when the melting process is accompanied by a notable Cp change.

    1 Linear Baseline It should be used for measurements in which no significant Cp changes are observed during melting. The linear baseline is generally used.

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 19

  • Au(S) Au(L), H298= 12,6 kJ/mol In(S) In(L), H298= 3.3 kJ/mol

    sigmoidal linear

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

    General Theory

    CuO/ZnAl2O4+H2 Cu/ZnAl2O4+H2O

    20

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

    DSC peak Correction

    General Theory

    In(S) In(L), H298= 3.3 kJ/mol

    Issues by uncorrected data

    1. Temperature on the peak point does not correspond to the melting temperature (but from physical point of view the sample temperature should be equal to melting point)

    2. After peak maximum the signal diminishes slowly. (Although it is known that the sample is completely molten)

    21

  • Bad thermal contact Long melting time Broad, low peak

    Good Thermal contact Short melting time Sharp peak

    The slope of the peak left side is depended on thermal resistance Peak area is the same and equals melting enthalpy.

    General Theory

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 22

  • small

    f(t) evolved heat F(t) measured signal g(t) response function

    g(t)=exp(-t/)

    The peak right side is depended on instrument time constant.

    1 < 2

    big

    General Theory

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 23

  • Original signal Time constant correction Full correction

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

    General Theory

    DSC peak Correction

    24

  • Theproper5esofthesystemsamplesensorstronglyinfluencetheexperimentalTAcurves

    Informa5onobtaineddependsonprocedureNotfundamentalproperty

    FeaturesofTASetup

    a)Reac5onAtmosphereb)Sizeandshapeoftheovenc)Sampleholdermateriald)Sampleholdergeometrye)Hea5ngratef)Thermocouple(wirediameter)g)Thermocoupleloca5onh)Response5me

    Characteris5csofthesample

    a) Par5clesizeb) Thermalconduc5vityc) Thermalcapacityd) Packingdensityofpar5cles(powder,pill,tablet)e) Sampleexpansionandshrinkingf) Samplemassg) Inertfillerh) Degreeofcrystallinity

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

    General Theory

    25

  • Dehydration of CaC2O4nH2O in an open crucible in a dry air flow (red curve) and in a static atmosphere (green curve).

    24n224+n23+1/22+21stage 2stage 3stage

    Influence of external gas flow Setup:NetzschSTAJupiter

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 26

  • Influence of external atmosphere Setup:NetzschSTAJupiter

    TG

    Dr. Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 27

  • Influence of external atmosphere

    Ar, 100ml/min

    Vacuum 10-4 bar

    k1

    DSCTGsampleholder,Sampleweight:10mg

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

    M=CuxZn1-x

    28

  • Influence of sample mass

    k1

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 29

  • Influence of heating rate

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

    Independent processes

    Ea1

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

    Subsequent processes

    Influence of heating rate

    La(OH)3LaOOH+H2O LaOOHLa2O3+H2O

    31

  • Competitive process processes

    Influence of heating rate

    Ea1

  • Influence of the pan material Setup:NetzschSTAJupiter

    Al Pt Al2O3 Ni Cu Quartz

    PyrolisisofFluoropolymer:TFEVDF,{C2F4}n{C2H2F2}m,F42inAlanAupans

    10Kpm,Ar,100ml/min

    in Al

    in Au

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 33

  • Setup:NetzschSTAJupiter

    Interac5onofTaandNbwithFluoropolymer:TFEVDF,{C2F4}n{C2H2F2}m,F42

    Strong exothermic reactions

    M

    -strong heat evolution, narrow T

    -2 stages by interaction -sharp weight loss due to reaction between two solid interfaces.

    Mass loss: reflects the available metal surface which is in contact with polymer.

    with A. Alikhanjan, and I. Arkhangelsky (2009)

    Ta-F42

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 34

  • Exothermic

    Endothermic (due to water traces)

    Setup:NetzschSTAJupiter

    Two effects coinsides resulting in endothermic effect.

    Strong exothermic reactions

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

  • Measurementininert.Isthesystemoxygenfree?Setup:NetzschSTAJupiter

    O2tracesof0.25ppm

    CuC2O40.5H2OCu+2CO2

    DSCTGsampleholder,Al2O3pan,Ar100ml/minSample:CuC2O40.5H2OWeight:9.1mg

    Cu+1/2O2CuO

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 36

  • Setup:NetzschSTAJupiter

    Ni+1/2O2NiO

    @RTO2tracesof1.7ppm

    DSCTGsampleholder,Al2O3pan,Ar100ml/minSample:Ni/MgAl2O4Weight:14.1mg

    Measurementininert.Isthesystemoxygenfree?

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 37

  • Setup:RubothermMSB

    TGsampleholder,Al2O3pan,Ar250ml/minSample:CuC2O40.5H2OWeight:301.8mg

    O2tracesof7ppm

    Measurementininert.Isthesystemoxygenfree?

    CuC2O40.5H2OCu+2CO2

    Cu+1/2O2CuO

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 38

  • =f/Hfo

    Hfo = 99.3J/g

    Hfo enthalpy of polymer with 100% degree of crystallinity

    Determina5onofcrystallinitydegree

    TFEVDF,{C2F4}n{C2H2F2}m,F42

    X-degree of crystallinity

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

  • TA-MS Coupling systems

    Skimmer coupling system

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

  • Capillary coupling system

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

    TA-MS Coupling systems

  • Main Problems of TA-MS coupling system

    Pressure reduction 103mbar 10-5mbar

    Condensation and secondary reactions Unfalsified gas transfer Different viscosity Demixing

    Attribution of a fragment to a chemical process Pyrolysis or evaporation MS fragmentation or sample behavior

    Overlapping of thermal processes hydrolysis and oxidation due to rest water and oxygen background in the feed.

    Kaiserberger (1999)

    Disadvantages: shock sensitive, no direct MS inlet.

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

  • (PulseTA) Adsorption of Methanol on -AlF3

    TA-MS curves for a PulseTA experiment on pretreated (2 h, 250 C; vacuum)

    Sample:AlF3Sampleweight:43.81mgm=0.15mg,N270ml/min

    M. Feist et. al. 2010

    Determining Lewis acidity

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

  • PTA curves of NiO/MgAl2O4 after reduction, isothermal at 45C with O2 injections, Interupted by a H2 pulse

    O(chemisorbed)/Ni(reduced)=0.22

    ** Assuming O/Ni=2, dNi=9nm in agreement with TEM Sample:Ni/MgAl2O4Sampleweight:30.8mgm=1.14mg,Ar100ml/min

    (PulseTA) Titration of Ni surface with O2

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

  • Resources

    J. Sestak, Thermophysical properties of solids (Academia, Prague, 1984)

    G. Hhne, W. Hemminger, H.-J.Flammersheim, Differential Scanning Calorimetry (Springer, Berlin, 1996)

    E. Moukhina, J. Therm Anal. Calorim. (2012) 109: 1203-1214

    http://www.netzsch.com

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

  • Acknowledgments

    Dr. Elena Moukhina, Netzsch Gertebau GmbH, Selb

    Dr. Jan Hanss, Netzsch Gertebau GmbH, Selb

    Dr. Michael Feist, HU Berlin

    Prof. Igor Arkhangelsky, MSU Moscow

    Dr. Alexander Dunaev, MSU Moscow

    thermal analysis

    Andrey Tarasov, Thermal analysis, Lecture series heterogeneous catalysis, FHI MPG, 26.10.12 46

  • Thank you!

    47