Analyzing & Testing

Business Unit

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Thermal Analysis Methods (Part 1):

TG, DSC, STA, EGA

Practical Applications of Thermal Analysis Methods in Material Science Krakow, 15 – 16 May, 2012 Ekkehard Post, NETZSCH Gerätebau, Wittelsbacher Str. 42, D-95100 Selb/Germany

Krakow 2012/ep

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Thermal Analysis Techniques

Krakow 2012/ep

Evolved Gas Analysis (EGA – MS, FTIR, GC-MS)

Differential

Scanning

Calorimetry

(DSC, DTA)

Thermo-

gravimetric

Analysis

(TGA)

Thermo-

mechanical

Analysis (TMA)

Dilatometry

(DIL)

Dynamic-

Mechanical

Analysis (DMA)

Thermal effects

from physical

and chemical

processes

(phase

transitions,

reactions);

specific heat

Mass changes

due to

evaporation,

decomposition

and interaction

with the

atmosphere

Dimensional

changes,

deformations,

viscoelastic

properties,

transitions,

density

Dielectric

Analysis

(DEA)

Dielectr.

constant

(permittivity),

loss factor,

conductivity,

resisitivity

(ion viscosity);

cure index (degr.

of cross-linking)

Thermophysical

Properties

Laser Flash

Analysis (LFA)

Heat Flow Meter

Guarded Hot

Plate etc.

Thermal

Conductivity

Thermal

Diffusivity

Specific Heat

Thermal

Expansion

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Thermogravimetric Analysis

First thermobalance were built by Kotaro Honda in 1915, working at

Tohoku Imperial University.

With this Instrument were

obtained the first TG-curves for

MnSO4• H20, CaCO3 and

CrCO3.

Krakow 2012/ep

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Thermogravimetry (TG):

Measuring Principle

Electronic microbalance – the sample’s gravitational force is continually evened out by the

electromagnetic force.

The needed current for the equilibrium represents the measurand and is recorded.

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.

Background:

- law of mass conservation

- mass change by reaction

separation/absorption of

gaseous materials

transition rate = f(m)

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Arrangements of Commercial TGAs

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Schematic of a Top Loading Balance

gas outlet

sample

cooling

cooling

hoistsample carrier

balancegas inletprotective

gas inletpurge

relief valve

pressure sensor

cover support

sample carrier

vacuum

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TG curve

Krakow 2012/ep

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

30

40

50

60

70

80

90

100

TG /%

-12.05 %

-18.81 %

-29.48 %

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TG and DTG curves

Krakow 2012/ep

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

30

40

50

60

70

80

90

100

TG /%

-6.0

-5.0

-4.0

-3.0

-2.0

-1.0

0

1.0

DTG /(%/min)

-12.05 %

-18.81 %

-29.48 %

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Stainless Steel in Humid Atmosphere

Krakow 2012/ep

Sample: Stainless Steel

Sample mass: ~ 500 mg

Crucible: Alumina Plate

Heating rate: 10/0 K/min

Atmosphere: Water vapor

Sensor: TG type S

2 days isothermal at 900°C

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Differential Scanning Calorimetry /

Differential Thermal Analysis

Krakow 2012/ep

Differential Scanning Calorimetry (DSC) is a Thermal Analysis technique in which the heat flow rate (power) to the sample is monitored against time or temperature while the temperature of the sample, in a specified atmosphere, is programmed ICTA; For better Thermal Analysis and Calorimetry, Edition III (1991)

FurnaceRefer.Sample

T

QPR

.

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DTA and DSC Principle

Krakow 2012/ep

During a phase transition a temperature difference

(heat flux difference) between the sample and

reference can be measured by means of a

thermocouple.

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Generation of the DSC/DTA Signal

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Magnesium Alloy

Krakow 2012/ep

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Second Order Phase Transitions - magnetic phase transition of iron (Lambda shape) -

200 400 600 800 1000 1200 1400 1600Temperature /°C

-1

0

1

2

3

4

5

6

7

DSC /(mW/mg)

Sample: Iron

1534.0 °C

1559.7 °C

266.1 J/g

926.4 °C1399.3 °C

770.2 °C 16 J/g 16.13 J/g

exoSample: Iron disk

Sample mass: 129.68 mg

Crucible: Pt+liner+lid

Sample holder: DSC-cp

Heating rate: 20 K/min

Atmosphere: Argon at 50 ml/min

melting magnetic A3 A4

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Phase diagrams - DSC

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Phase diagram of NiAl

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Phase diagram of NiAl

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Heat Capacity of Molydenum

Krakow 2012/ep

-200 -100 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300

Temperature /°C

0.15

0.20

0.25

0.30

0.35

0.40

Spe

cific

Hea

t /J/

(g K

)

Mo: Literature

Mo: Measurement

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Simultaneous Thermal Analysis (STA)

Simultaneous Techniques

This refers to the application of two or more techniques to a (single)

sample at the same time. A hyphen is used to separate the

appreviations, e.g. simultaneous thermogravimetric analysis and

differential scanning calorimetry (TGA-DSC).

TG-DSC/DTA

Simultaneous mass change and energetic information on one and the same

sample under absolutely identical measurement conditions

ICTA 1991

Krakow 2012/ep

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Simultaneous Thermal Analysis (STA)

FurnaceRefer.Sample

T

QPR

.

TG + DSC = STA

Thermogravimetry Differential Scanning

Calorimetry

TG, DSC applied simultaneously to the same sample.

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TG – DSC Measurement of Fe2O3

Krakow 2012/ep

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Heating and Cooling of MnO2

200 400 600 800 1000 1200 1400Temperatur /°C

-4

-2

0

2

4

6

DSC /(mW/mg)

86

88

90

92

94

96

98

100

102

TG /%

Sample: MnO2

619.1 °C

958.2 °C1200.7 °C

179.7 J/g

71.45 J/g

432.1 J/g

-9.20 %

-3.07 %

-0.23 %

1147.8 °C

-71.83 J/g

exo

Krakow 2012/ep

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Different Furnaces for Different Applications

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Sample Carriers

Krakow 2012/ep

TG-DSC- cp

TG-DSC

TG-DTA TG

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Special STA furnaces increase

application range

Krakow 2012/ep

2400°C Furnace

Water Vapour Furnace

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Scheme of the Tungsten Furnace

Maximum heating and cooling rate: 100 K/min

Atmospheres: Helium, vacuum

Maximum temperature at sample: 2400°C

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Tungsten Furnace Guarantees very

clean Atmospheres

At 2400 °C, the vapor pressure of graphite is 10-3 torr, therefore no high vacuum can be

applied. The tungsten furnace of the STA 429 allows measurements in high vacuum

(10-5 torr) up to 2400 °C. This is essential for clean atmospheres and Knudsen cell tests

Krakow 2012/ep

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Melting and Crystallization of Vanadium

Created with NETZSCH Proteus software

1760 1780 1800 1820 1840 1860 1880 1900 1920 1940Temperature /°C

0

20

40

60

80

100

120[1.2]

TG /%

2

3

4

5

6

7

DTA /(µV/mg)

Main 2009-07-03 08:08

heating

cooling

theoretical values: melting1890°C

sample Vanadium, 20 K/min, He

1887.1 °C

1879.9 °C

-38.74 µVs/mg

38.47 µVs/mg

exo

Temperature program: RT to 1970°C to 1600°C Heating rate: 20 K/min Atmosphere: He Crucible: ZrO2 „liner“ in W crucibles

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Sapphire

Created with NETZSCH Proteus software

2000 2020 2040 2060 2080 2100Temperature /°C

6

7

8

9

10

11

12

DTA /(µV/mg)

-300

-250

-200

-150

-100

-50

0

50

100

TG /%

Main 2009-07-03 12:01

Melting of Sapphire

2nd heating

2055.0 °C

52.43 µVs/mg

exo

Temperature range: RT to 2100°C

Heating rate: 75 K/min

Crucible: W with lid

Atmosphere: He

Sample weight: 12.34 mg

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EGA methods combined with TGA

MS Mass Spectrometry

FTIR Fourier Transform Infrared

Spectroscopy

GC-MS Gas Chromatography with MS

GC-FTIR GC with FTIR

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MS Capillary Coupling

Krakow 2012/ep

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Hydromagnesite

(STA-MS Capillary)

mass 25.98 mg

temp. 25 ... 960°C

HR 10 K/min

Air, 80 ml/min

Mg5(CO3)4 (OH)2 * 4 H2O

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16th March 2011

Krakow 2012/ep

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Tools to Investigate such Events?

Krakow 2012/ep

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0

1.0

2.0

3.0

4.0

5.0

Ion Current *10-9 /A

500 600 700 800 900 1000Temperature /°C

100

102

104

106

108

110

112

114

TG /%

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

DTG /(%/min)

BCR-276

in N2 and water vapor atmosphere

5 K/min

2 amu

DTG

TG

Zircaloy Zirc-4 BCR-276

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MS-Skimmer Coupling

Krakow 2012/ep

10 mbar-1

Sample

Heater

Sample carrier

Gas overflow

Quadrupol analyzer

Ion source

Skimmer

Orifice

1013 m

bar

10 mbar-5

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Melting behaviour of CuGaSe2

Krakow 2012/ep

http://www.nrel.gov/docs/fy03osti/33997.pdf

NREL/SR-520-33997

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CuGaSe2

Krakow 2012/ep

I2

Impurities: Selenium excess, Iodine

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STA – MS – FTIR Coupling

Krakow 2012/ep

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TG – FTIR Measurement of PVC

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STA – GC – MS Coupling

Krakow 2012/ep

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Thank you for your attention