proper detail is present in slides about TGA , i am the student of Punjab university metallurgy and material engineering ,

1. THARMOGRAVITOMETRIC ANALYSIS
HAFIZ ADNAN HANIF
E11-341
METALLURGY AND
MATERIAL ENGINEERING
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2. Introduction
 TGA is a technique which measures the change in
the mass of a sample over a range of
temperatures.
 Principle:
• The basic principle of TGA is that as a sample is
heated, its mass changes. This change can be
used to determine the composition of a material or
its thermal stability, up to 1000oC. Usually, a
sample loses weight as it is heated up due to
decomposition, reduction, or evaporation

3. What TGA Can Tell You
•Thermal Stability of Materials
•Oxidative Stability of Materials
•Composition of Multi-component Systems
•Estimated Lifetime of a Product
•Decomposition Kinetics of Materials
•The Effect of Reactive or Corrosive Atmospheres
on Materials
•Moisture and Volatiles Content of Materials

4. Type Of Thermogrvimetry
1. Isothermal / Static Thermogravimetry
2. Quasistatic Thermogravimetry
3. Dynamic Thermogravimetry
1. Isothermal/ Static Thermogravimetry:
In this technique the sample weight is
recorded as a function of time at
constant temperature.
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5. 2.Qasistatic Thermogravimetry:
In this technique the sample is heated to
constant
weight at each of the series of increasing
temperature.
3. Dynamic Thermogravimetry:
In this technique a sample is heated in
an environment whose temperature is
changing in predetermine manner
generally at linear rate.
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6. Thermogravimetric Curve:
 A to B - Thermal
stability of material.
 B to C -Weight loss.
 C – Procedural
decomposition
temperature.
 D- Final temperature
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A
B
C
D

7. Factor Affecting TGA Curve:
A. Instrumental factor:-
1. Heating Rate
2. Furnace atmosphere
3. Sample Holder
B. Sample
Characteristic:-
1. Effect of sample
mass
2. Effect of sample
particle size
3. Effect of heat
reaction
4. Compactness of
sample
5. Previous history of
sample
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8. Instrumentation
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9. Components of
Instrumentation:
A. Recording balance
B. Sample Holder
C. Furnace
D. Furnace temperature
programmer/Controller
E. Recorder
F. Thermobalance
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10. A. Balance:-
Recording balance
1. Deflection balance
i. Beam type
ii. Spring/ Helical type
iii. Cantilever type
iv. Torsion type
2. Null balance
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11. 1. Deflection balance:-
i. Beam type:-
A conversion of
beam deflection
about the fulcrum
into a suitably
identifiably weight
change.
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12. ii.Spring/Helical type:-
An elongation or
contraction of
spring with weight
change. This
changes the length
of the spring .
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13. iii. Cantilever type:-
 One end of the
beam is fixed &
other end on which
the sample is
placed, is free to
undergo deflection.
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14. iv. Torsion type:-
 In this type of
balance the beam
is attach to torsion
wire.
 The wire is fixed at
one or both ends
so that deflection of
beam are
proportional to
weight change.
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15. 2. Null point balance:-
 In this balance
there should be a
sensor to detect
the deviation of the
balance to detect
the null position .
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16. B. Sample Holder:-
Types of sample holder:-
1.Shallow Pans
2.Deep crucibles
3.Loosely covered crucibles
4.Restort cups
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17. 1.Shallow Pan:
Used for such sample necessary to
eliminate diffusion as a volatile material.
2. Deep Crucible:
Used to study industrial scale calcination
& surface area measurement.
3.Loosely curved crucible:
Used in self generated atom study.
4. Retord cups:
Useful in boiling point study.
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18. C.Furnace:-
 Position of furnace with respect to
balance:
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A B C

19. The choice of furnace heating element and type of
furnace depend upon the range being studies:-
Temperature Material
 1100˚c
 1100-1500˚c
 1100- 1750 ˚c
 Nichrome
 Platinum /Alloy of
rhodium
 Tungsten
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20. D.Temperature
Measurement:-
 The most common method is
thermocouple.
 The temperature 1100,chromel/alumel
thermocouple are made up of alloys of
Pt and rhodium are used.
 Higher temperature tungsten or
rhenium thermocouple are used.
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21. E. Recorder:-
Two Types:-
A. Time-base potentiometric strip chart
recorder
B. X-Y recorder
Advantage:-
1. To check the heating rate of the
furnace for linearity.
2. X,Y recorder we get curve having plot
of weight directly against temperature.
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22. F. Thermobalance:-
 It records continuously weight change of
the sample as a function of temperature.
 The sensitivity of balance depends on
the size of the sample used.
 The temperature recorded to an
accuracy of better than ±1%
 The weight loss recovered to an
accuracy ±1%
 In market large number of balance are
available.
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23. Applications:-
 Purity and thermal stability.
 Solid state reaction.
 Decomposition of organic and inorganic
compound.
 Determining composition of material.
 Corrosion of metals in various
atmosphere.
 Pyrolysis of coal , petroleum and wood.
 Roasting and calcination of minerals.
 Evaluation of gravimetric precipitates.
 Oxidative and Reductive stability.
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24. Thermogravimetric analyses and mineralogical study of polymer
modified mortar with silica fume
RESEARCH ARTICLE
Alessandra Etuko Feuzicana de Souza Almeida*; Eduvaldo Paulo Sichieri

25. RESERCH ARTICLE
TGA curves of pastes with silica fume content of 5% and 10% respectively.
It can be seen that TGA curves for these pastes consist of four zones:
 ~ 25-123.3 °C: dehydration of pore water
 ~ 123.3-420 °C: dehydration of calcium silicate hydrates
 ~ 420-480 °C: dehydroxylation of calcium hydroxide
 ~ 480-730 °C: decarbonation of CaCO3

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