Thermal Analysis

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First SIM² - WORKSHOP
Thermal analysis (TGA/DSC):
practical aspects
TGA – Thermogravimetric Analysis
DSC – Differential Scanning Calorimetry
Jacek Chwast
[email protected]
Geo-Instituut
23.01.2013
Measurement conditions
furnace
Netzsch STA 409 PC Luxx®:
- T [25 – 1000 °C]
- heating rate 10 °C/min
- N2 atmosphere (60 ml/min)
- alumina crucibles
- simultaneous measurement of mass
change (TG) and heat flow (DSC)
- 1 analysis (25100025 °C) = 3 hrs
microbalance
2
Measurement conditions
furnace
Netzsch STA 409 PC Luxx®:
- T [25 – 1000 °C]
- heating rate 10 °C/min
- N2 atmosphere (60 ml/min)
- alumina crucibles
- simultaneous measurement of mass
change (TG) and heat flow (DSC)
- 1 analysis (25100025 °C) = 3 hrs
sample + reference
microbalance
3
Thermal analysis (TGA/DSC) in a nutshell
TG analysis – mass (T)
DSC analysis – heat flow (T)
TG /mg
DTG /(mg/min)
0.000
[1]
0.0
-0.500
[1] cemI 1A 4d.dsv
TG
DTG
-1.000
-0.1
-0.1
-1.500
Onset*: 429.2 °C
-0.2
-2.000
-0.2
-2.500
[1]
100.0
200.0
300.0
400.0
500.0
600.0
700.0
Temperature /°C
800.0
900.0
-0.3
1000.0
Examples of thermal reactions resulting in
mass change, measured by TG analysis:
- loss of free water
- loss of bound water
- decomposition
TG applications:
- identification and quantification of sample
components
- thermal stability studies
Examples of thermal reactions resulting in
heat flow, measured by DSC analysis:
- crystallization
- melting
- glass transitions
DSC applications:
- thermodynamic characterization of pure
substances
- quality control: sample purity
4
- thermal stability studies
Sample compatibility
Requirements:
- no reaction with alumina crucible
- no expansion or creep during thermal decomposition
Compatible materials (KUL expertise):
- clays and other geological materials
- cements
- slags
Limitations:
- polymers can be hazardous, as they can foam at high
temperatures,
- compatibility assessment is necessary for new materials
5
Evaluation of new materials
Compatibility assessment:
• by providing a reference to a thermal analysis
or
• by burning the sample in a furnace
at the conditions foreseen for the measurement:
–
–
–
–
sample composition
temperature range (max. 1000 °C)
inert atmosphere
alumina crucible
6
Sample preparation
1) Sample form:
–
–
–
fine powders
compact solids
films, fibers
2) Ensure good thermal contact between
sample and heat flux-sensor:
–
powders: evenly distributed at the bottom
of the sample crucible, gently tamped
3) Always use the same
sample mass (~ 10-30 mg)
7
Analysis of results
Software: NETZSCH Proteus® (Marsh procedure)
Quantification of portlandite (Ca(OH)2) content in cement
~430°C: Ca(OH)2 -> CaO + H2O↑
TG /mg
0.000
DTG /(mg/min)
[1]
0.0
-0.500
[1] cemI 1A 4d.dsv
TG
DTG
-1.000
-0.1
-0.1
-1.500
Onset*: 429.2 °C
-0.2
-2.000
-0.2
-2.500
[1]
100.0
200.0
300.0
400.0
700.0
600.0
500.0
Temperature /°C
800.0
900.0
-0.3
1000.0
8
Analysis of results
Software: NETZSCH Proteus® (Marsh procedure)
Quantification of portlandite (Ca(OH)2) content in cement
~430°C: Ca(OH)2 -> CaO + H2O↑
TG /mg
[1] cemI 1A 4d.dsv
TG
-1.700
-1.800
mass
loss
-1.900
-2.000
[1]
-2.100
400.0
420.0
440.0
460.0
Temperature /°C
480.0
500.0
9
Analysis of results
Software: NETZSCH Proteus® (Marsh procedure)
Quantification of portlandite (Ca(OH)2) content in cement
~430°C: Ca(OH)2 -> CaO + H2O↑
TG /mg
[1] cemI 1A 4d.dsv
TG
-1.700
-1.800
-1.900
-2.000
[1]
-2.100
400.0
420.0
440.0
460.0
Temperature /°C
480.0
500.0
10
Analysis of results
Software: NETZSCH Proteus® (Marsh procedure)
Quantification of portlandite (Ca(OH)2) content in cement
~430°C: Ca(OH)2 -> CaO + H2O↑
TG /mg
[1] cemI 1A 4d.dsv
TG
-1.700
Mass Loss (Marsh):
431.7 °C
Onset:
440.4 °C
Inflection:
Mass Change: -0.258 mg
-1.800
-1.900
-2.000
[1]
-2.100
400.0
420.0
440.0
460.0
Temperature /°C
480.0
500.0
11
Contact information and reservations
Contact / Training:
Jacek Chwast
[email protected]
tel. +32 16 3 27593 or +32 16 3 27580
Responsible professor: Jan Elsen
TG /DSC instrument:
Geo-Instituut
Celestijnenlaan 200c
Room 01.83
Reservations:
- fill in the reservation list in the room 01.83
12
Thank you for your attention
Questions?
13
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