It’s Hot in Here … Let’s talk Thermal
Naaimat Muhammed
Thermal Methods
Introduction
Thermal analytical methods monitor differences in some sample property as the
temperature increases, or differences in temperature between a sample and a standard as
a function of added heat. These methods are usually applied to solids to characterize the
materials.
A general accepted definition of thermal analysis is a group of techniques in which a
physical property of a substance and/or its reaction products is measured as a function of
temperature while the substance is subjected to a controlled temperature program.
We will confine to three of the methods, which provide primarily chemical rather than
physical information about samples of matter.
1. Thermogravimetry (TG)
2. Differential thermal analysis (DTA)
3. Differential scanning calorimetry (DSC)
Thermogravimetric Methods
In thermo gravimetric analysis, the mass of a sample in a controlled atmosphere is
recorded continuously as a function of temperature or time as the temperature of the
sample is increased (usually linear with time). Thermogravimetry is the measurement of
the mass of a sample as the temperature increases. This method is useful for determining
sample purity and water, carbonate, and organic content; and for studying
decomposition reactions.
Differential Thermal Analysis (DTA)
Differential thermal analysis is the measurement of the difference in temperature between
a sample and a reference as heat is applied to the system. This method is sensitive to
endothermic and exothermic processes including: phase transitions, dehydration, and
decomposition, redox, or solid-state reactions.
Differential Scanning Calorimetry (DSC)
Differential scanning calorimetry independently measures the rate of heat flow to a
sample and a standard that are at the same temperature. Data is taken by monitoring the
differential heat flow as a function of temperature. DSC is useful to make the same
measurements as DTA and has the added capability to measure heat capacities.
Instrumentation
