1

Thermal Analysis

An introduction

Ralf Franke NETZSCH Gerätebau GmbH, Selb 03.07.2005

2 ISM 2005 Thermal Analysis – An Introduction

• Introduction

definition

information available

• Techniques and instruments

TG, DSC, STA, STA-MS, TG-FTIR, DIL, TMA, DMA,

• Visit of the NETZSCH Application laboratory

• Starting a DSC Measurement

• TG „Workshop“

Outline

4 ISM 2005 Thermal Analysis – An Introduction

Definition (ASTM E 473-85):

Thermal Analysis is a group of techniques in which a

physical property of a substance is measured as a

function of temperature while the substance is

subjected to a controlled-temperature program.

(ICTA, 1980)

Thermal Analysis

5 ISM 2005 Thermal Analysis – An Introduction

Temperature is one of the most frequently measured quantities.

Measurement with thermocouples or resistance thermometers.

Thermocouples for measuring temperature differences according to the

Seebeck effect:

If an electric conductor is exposed to a temperature gradient, an electron flow is generated inside the conductor, which causes an electromagnetic force (EMF, thermocouple voltage).

EMF = resulting voltage, S – Seebeck Coefficient.; t1 – temperature at the soldering joint, t2 – reference temperature

Temperature Measurement

soldering joint

Metal A

Metal B

EMF

6 ISM 2005 Thermal Analysis – An Introduction

A suitable thermocouple can be formed by connecting two metal wires

with different thermal properties.

Seebeck coefficient for some selected materials (in µV/°C at 0°C)

Aluminium 3.5 Selenium 900

Cadmium 7.5 Silicon 440

Constantan (40% Ni + 60% Cu) –35 Silver 6.5

Copper 6.5 Tellurium 500

Germanium 300 Tungsten 7.5

Iron 19

Nickel-Chromium 25

Nickel –15

Platinum 0

Rhodium 6

Thermocouples

According to this list e.g. nickel-chromium and constantan (type E) would be a good combination.

7 ISM 2005 Thermal Analysis – An Introduction

Thermocouple type

(+) Leg

(-) Leg

Generated emf change in µV/°C

(reference junction at 0°C)

approx. working temperature range

Notes

at 100°C

at 500°C

at 1000°C

K Ni-Cr (Chromel)

Ni-Al (Alumel)

42 43 39 0 …1100°C most suited for oxidising atmospheres

T Cu CuNi (Constantan)

46 - - -185 … 300°C excellent for low temperatures

J Fe CuNi 54 56 59 20 … 700°C used in reducing atmospheres as an unprotected thermocouple

N NiCrSi

(Nicrosil)

NiSi 30 38 39 0 … 1100°C very stable output signal at high temperatures

E NiCr CuNi 68 81 - -200 … 800°C highest thermal emf per °C

R Pt13Rh Platin-13%Rhodium

Platinum 8 11 13 0 … 1600°C high resistance to oxidation and corrosion

S Pt10Rh Platin-10%Rhodium

Platinum 8 9 11 0 … 1550°C similar characteristics to type R

B Pt30Rh Platin-30%Rhodium

Pt6Rh Platinum-6%Rhodium

1 5 9 0 ... 1600° similar characteristics to type R and S

Thermocouples according to ITS 90 and IEC 584-1

8 ISM 2005 Thermal Analysis – An Introduction

ASTM E 473 – 85:

Thermogravimetry is a

technique in which the

mass of a substance is

measured as a function of

temperature while the

substance is subjected to

a controlled-temperature

program.

Thermogravimetry (TG)

9 ISM 2005 Thermal Analysis – An Introduction

Thermogravimetry (TG)

gas outlet

sample

cooling

cooling

hoistsample carrier

balancegas inletprotective

gas inletpurge

relief valve

pressure sensor

cover support

sample carrier

vacuum

10 ISM 2005 Thermal Analysis – An Introduction

Thermogravimetry (TG)

Some features:

• RT – 1000°C • resolution: 0.1 µg • vacuum-tight • autovac • ASC • TG-FTIR /TG-MS

11 ISM 2005 Thermal Analysis – An Introduction

100.0 200.0 300.0 400.0 500.0 600.0 700.0 800.0 900.0Temperature /°C

40.00

50.00

60.00

70.00

80.00

90.00

100.00

TG /%

-12.26 %

-30.02 %

Residual Mass: 38.57 % (949.6 °C)

-19.15 %

Thermogravimetry (TG)

TG 209 Iris F1 sample mass: 10.12 mg crucible: Al2O3

atmosphere: air, 30 ml/min heating rate: 10 K/min

12 ISM 2005 Thermal Analysis – An Introduction

and a reference materialis measured as a function of

temperature while the substance and reference is

subjected to a controlled-temperature program.

Differential Scanning Calorimetry (DSC)

reference sample

heat flow

temperature and heat flow sensor

thermal resistance

heating and cooling

ASTM E 473 – 85:

Differential Scanning

Calorimetry (DSC) is a

technique in which the

difference in energy

inputs into a substance

13 ISM 2005 Thermal Analysis – An Introduction

Differential Scanning Calorimetry (DSC)

14 ISM 2005 Thermal Analysis – An Introduction

Differential Scanning Calorimetry (DSC)

Exchangeable DSC Sensor Types

new t–Sensor

-180 ... 700°C

short response time silver sensor

m–Sensor

-150 ... 400°C

high sensitivity

silicon sensor

15 ISM 2005 Thermal Analysis – An Introduction

Differential Scanning Calorimetry (DSC)

DSC 204 F1 Phoenix sample mass: 20.97 mg crucible: Al atmosphere: nitrogen 30 ml/min heating rate: 10 K/min

melting

cold crystallization glass transition

Heat flow

16 ISM 2005 Thermal Analysis – An Introduction

STA: Principle

FurnaceRefer.Sam ple

DT

QPR

.

TG + DSC = STA

Thermogravimetry Differential Scanning Calorimetry

Simultaneous Thermal Analysis

TG, DSC applied to the same sample.

17

TG (mass changes)- and DSC (caloric)-effects are measured on one sample in one run in one system. Comparability of results is ensured:

• no influence of material inhomogeneity • no influence of sample preparation • no influence of measurement conditions • faster measurement times

Advantages of STA method

18 ISM 2005 Thermal Analysis – An Introduction

STA: Schematic Setup

19 ISM 2005 Thermal Analysis – An Introduction

STA: Specifications

Top features of Netzsch STAs:

• -160 ... 2000°C • resolution: 0.1 µg • vacuum-tight • low drift (~mg/h) • coupling with MS/FTIR

20 ISM 2005 Thermal Analysis – An Introduction

STA: Application

Dehydration:

Montmorillonit Montmorillonit

Böhmit Diaspor & Hydrargillit

Kaolinit

Decomposition

of CaCO3

burn-up of organics

STA 409 PC sample mass: 52.46 mg crucible: Pt

atmosphere: air, 75 ml/min heating rate: 10 K/min

21 ISM 2005 Thermal Analysis – An Introduction

STA is a powerful tool, however ...

... no direct chemical identification of the evolved gases and thus of the sample!

EGA using MS and FTIR !

Add-on: Monitoring of the partial pressures of the sample atmosphere (consumption of gas?)!

STA-MS

22 ISM 2005 Thermal Analysis – An Introduction

STA-MS

NETZSCH Skimmer ®

+ STA 409 CD

NETZSCH QMS 403 C Aëolos ® + STA 449 Jupiter ®

23 ISM 2005 Thermal Analysis – An Introduction

Simultaneous measuring of STA, MS and FTIR!

Consequent heating of the entire coupling interface (up to 300°C)!

prevention of condensation of evolved gases

enhance the traceability of evolved gases

minimize the risk of blocking of the coupling capillary

STA-MS: Capillary Coupling (Aëolos®)

24 ISM 2005 Thermal Analysis – An Introduction

STA-MS-interface within furnace!

Best prevention of condensation of evolved gases

enhanced sensitivity compared to capillary coupling

STA-MS: Skimmer® Coupling

25 ISM 2005 Thermal Analysis – An Introduction

STA-MS: Application

STA 449 C + Aëolos mass: 29.53 mg crucible: Pt

atmosphere: Ar, 50 ml/min heating rate: 10 K/min

26 ISM 2005 Thermal Analysis – An Introduction

STA-MS: Application

STA 449 C + Aëolos mass: 29.53 mg crucible: Pt

atmosphere: Ar, 50 ml/min heating rate: 10 K/min

27 ISM 2005 Thermal Analysis – An Introduction

TG-FTIR-MS

BRUKER

TENSORTM27 NETZSCH

TG 209C F1 IRIS®

NETZSCH QMS Aeolos®

28 ISM 2005 Thermal Analysis – An Introduction

TG-FTIR

FTIR gas cell

(230°C)

transfer line

(230°C)

control

thermocouple adaptor head

(230 °C)

control

thermocouple

micro furnace

sample

sample carrier

control

thermocouple

IR detector

TG cell

gas outlet

29 ISM 2005 Thermal Analysis – An Introduction

100 200 300 400 500 600 700 800 900Temperature /°C

30

40

50

60

70

80

90

100

TG /%

0

0.05

0.10

0.15

0.20

Gram Schmidt

-6.0

-5.0

-4.0

-3.0

-2.0

-1.0

0

1.0

DTG /(%/min)

-12.05 %

-18.81 %

-29.48 %

TG-FTIR

TG 209 Iris F1 - FTIR sample mass: 10.12 mg crucible: Al2O3

atmosphere: air, 30 ml/min heating rate: 10 K/min

30 ISM 2005 Thermal Analysis – An Introduction

TG-FTIR

31 ISM 2005 Thermal Analysis – An Introduction

F:\measurement\2004\001-3-04\001-3-04-02\490.0 CaC2O4_air_1 10.120 | NETZSCH TG 209 | F:\measurement\2004\CaC2O4\001-3-04-02.dt2

F:\measurement\0_libspectra\CO.01 CARBON MONOXIDE

F:\measurement\0_libspectra\CO2.01 CARBON DIOXIDE

1000150020002500300035004000

Wavenumber cm-1

0.0

0.5

1.0

1.5

2.0

2.5

Absorb

ance U

nits

TG-FTIR

32 ISM 2005 Thermal Analysis – An Introduction

Dilatometry (DIL)

A technique in which a dimension of a substance under negligible load is measured as a function of temperature while the substance is subjected to a controlled temperature program.

33 ISM 2005 Thermal Analysis – An Introduction

Dilatometry (DIL)

34 ISM 2005 Thermal Analysis – An Introduction

Dilatometry (DIL)

Some features: • -260°C – 2800°C • vaccum-tight • inert, oxdizing and reducing atmospheres • up to 0.125 nm/digit resolution for 500 µm range • solids, pastes, powders, molten metals • Dil-MS and Dil-FT-IR

35 ISM 2005 Thermal Analysis – An Introduction

Dilatometry (DIL)

Dil Application Example

Dil 402 C Sample: Quartz Crystal Sample holder: fused silica Heating rate: 2 Kmin Atmosphere: Helium

36 ISM 2005 Thermal Analysis – An Introduction

Thermomechanical Analysis (TMA)

TMA – Thermomechanical-Analysis A technique in which the deformation of a substance under non-oscillatory load is measured as a function of temperature while the substance is subjected to a controlled temperature program.

DIN 51005; ASTM E 831

37 ISM 2005 Thermal Analysis – An Introduction

Thermomechanical Analysis (TMA)

TMA – Thermomechanical-Analysis

TMA 202 TMA 402

38 ISM 2005 Thermal Analysis – An Introduction

Thermomechanical Analysis (TMA)

TMA – Thermomechanical-Analysis

TMA 202

Some features: • -150°C –600°C • heating rates up to 50 K/min • sensitivity: 1 dig./1.25 nm • load: 0.01 to 1 N

39 ISM 2005 Thermal Analysis – An Introduction

Thermomechanical Analysis (TMA)

TMA Application Example

TMA 202 Sample: PMMA Mode: Exansion Sample length: ~1.8 mm Sample holder: Fused Silica Heating rate: 10 K/min Atmosphere: Air

40 ISM 2005 Thermal Analysis – An Introduction

Dynamic Mechanical-Analysis (DMA)

Determination of the mechanical properties of a sample

under an oscillating load and as a function of temperature,

time and frequency

DMA - Dynamic Mechanical Analysis

41 ISM 2005 Thermal Analysis – An Introduction

Dynamic Mechanical-Analysis (DMA)

42 ISM 2005 Thermal Analysis – An Introduction

Dynamic Mechanical-Analysis (DMA)

Some features:

• 8 N static and ± 8 N dynamic force • frequency range: 0.01 - 100 Hz • modulus range E´: 10-3 – 106 MPa • tan range: 0.00006 to 10 • -170°C – 600°C • heating rate: 0.1 – 20 K/min

43 ISM 2005 Thermal Analysis – An Introduction

Dynamic Mechanical-Analysis (DMA)

DMA Measuring Modes

Shear

Tension 3-Point Bending

Compression / Penetration

Single/Dual Cantilever

Prestress (Static) Oscillation Sample

44 ISM 2005 Thermal Analysis – An Introduction

Dynamic Mechanical-Analysis (DMA)

DMA Application Example

-80 -60 -40 -20 0 20 Temperature /°C

0.000

0.200

0.400

0.600

0.800

1.000

tan d

500.0

1000.0

1500.0

2000.0

2500.0

3000.0

3500.0

4000.0

4500.0

E' /MPa

0

200

400

600

800

1000

E'' /MPa

1.00 Hz

2.00 Hz

5.00 Hz

10.00 Hz

Rubber

Peak: -59 °C, 0 .806

Onset: -70 °C, 4679 .3 MPa

Peak: -64 °C, 880 .4 MPa

DMA 242 C sample holder: single cantilever 16 mm amplitude: ± 40 µm

atmosphere: static air heating rate: 2 K/min

45 ISM 2005 Thermal Analysis – An Introduction

A low voltage AC signal (input)

is applied at one electrode

The response signal detected

at the other electrode (output)

is attenuated and phase shifted

Fundamental Principle of DEA ASTM E 2038 and E 2039

Dielectric Sensor: • Alignment of dipoles • Mobility of ions

46 ISM 2005 Thermal Analysis – An Introduction

The NETZSCH DEA Series for Cure Monitoring of Reactive Resins

Dielectric Analysis (DEA)

– DEA 230 for most thermosets, adhesives, paints and coatings

– DEA 231 for fast curing resins as SMC/BMC and UV curing

– DEA 234 CurePak™ for continous processes

– MiniPress MPS 235

Implantable (disposable) sensors

Robust and reusable sensors

Surface (fringing field) or bulk measurements

For laboratory tests and curing in process (ovens, molds, presses)

Multi-channel instruments available

for DEA signal and temperature

47 ISM 2005 Thermal Analysis – An Introduction

PARALLEL PLATE

ELECTRODES

COMB ELECTRODES INTERDIGITAL

CO-PLANAR

BULK FIELD FRINGE FIELD

POLYMER

DEA Sensor Geometry and Types

Monotrode Sensor in Spring Mold Tool Mount Sensor

Micron Sensor

IDEX Sensor

48 ISM 2005 Thermal Analysis – An Introduction

Ion Viscosity and Loss Factor for the Flowing and Curing of an Epoxy Resin

lowest viscosity

best flow

highest viscosity

end of curing

+

+

49 ISM 2005 Thermal Analysis – An Introduction

Buoyancy Effect for STA/TG Measurements Workshop

50 ISM 2005 Thermal Analysis – An Introduction

Buoyancy:

The sample „swims“ in

the atmosphere. The

buoyancy (Archimedes

principle) becomes

smaller with increasing

temperature; as a

consequence the

balance shows an

apparent mass increase.

51 ISM 2005 Thermal Analysis – An Introduction

Buoyancy and Convection - 1

Depending on

Atmosphere

Type of the sample carrier

Heating rate

Crucible volume

Fa = g • ρ • VK

ΔFa = g • VK • (ρ1- ρ2)

Ar

N2

He

52 ISM 2005 Thermal Analysis – An Introduction

Buoyancy and Convection - 2

100 200 300 400 500 600 700 800 900Temperature /°C

-0.30

-0.20

-0.10

-0.0

0.10

0.20

0.30

0.40

TG /mg

Depending on

Atmosphere

Type of the sample carrier

Heating rate

Crucible volume

20 K/min

2.5 K/min 10 K/min

53 ISM 2005 Thermal Analysis – An Introduction

Buoyancy and Convection - 3

Depending on

Atmosphere

Type of the sample carrier

Heating rate

Crucible volume

For large sample masses

(big crucible volume) it is

recommended to carry out

the correction curve with an

inert material (e.g. Al2O3).

54 ISM 2005 Thermal Analysis – An Introduction

100 200 300 400 500 600Temperatur /°C

0

0.100

0.200

0.300

0.400

0.500

0.600

0.700

0.800

0.900

TG /mg

DTA/Al2O3-Tiegel

DSC/Pt-Tiegel

Buoyancy and Convection - 4

Depending on

Atmosphere

Type of the sample carrier

Heating rate

Crucible volume

DTA/Al2O3 crucibles

DSC Pt crucibles

55 ISM 2005 Thermal Analysis – An Introduction

Buoyancy and Convection - 5

Ca oxalate measurement

without correction

56 ISM 2005 Thermal Analysis – An Introduction

Buoyancy and Convection - 6

TG/DSC measurement

in Pt crucibles,

Sample mass: 24.69 mg

Ca oxalate measurement

with correction

57 ISM 2005 Thermal Analysis – An Introduction

Mass Calibration - 1

Method 1:

Taking the recommendation from DIN 51 006 into consideration

- Call up the calibration mode of the instrument (if available)

- Put on one or several standard weights at room temperature

(in case of STA 409 PC Luxx this will be done automatically)

- compare the displayed mass with the nominal one

Method 2: Using Calcium Oxalat Monohydrate

- Calciumoxalat Monohydrat shows between room temperature and

950°C three well separated mass loss steps

- Compare the experimental mass loss values (corrected curve) with

the nominal ones

58 ISM 2005 Thermal Analysis – An Introduction

Mass Calibration - 2

59 ISM 2005 Thermal Analysis – An Introduction

Mass Calibration - 3

60 ISM 2005 Thermal Analysis – An Introduction

Example: Calculation of theretical mass loss steps

Molecular weights:

Ca = 40 g/mol; C= 12 g/mol; O2 = 32 g/mol, H2 = 2g/mol,

C02 = 44 g/mol, CO = 28 g/mol

1) 146 g/mol to 128 g/mol = (18/146) = mass loss 12.4%

2) 128 g/mol to 100 g/mol = (28/146) = mass loss = 19.1%

3) 100 g/mol to 56 g/mol = (44/146) = mass loss = 30.1 %

All calculations have to be related to the starting mass of CaC2O4 x H20

(146 g/mol)

Mass Calibration - 4