Published Online: 15 SEP 2006
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Dunn, J. G. 2006. Thermogravimetry. Encyclopedia of Analytical Chemistry. .
- Published Online: 15 SEP 2006
Thermogravimetry (TG or TGA) is a technique in which the mass of a substance is measured as a function of temperature whilst the substance is subjected to a controlled temperature program.1, 2 Commonly materials can be heated or cooled in the temperature range from −160 to 1600°C at rates of fractions of a degree per minute up to 100°C min−1. Sample sizes are from 10–100 mg, although apparatus is available which can take larger sample masses. Different atmospheres can be used, from inert gases such as nitrogen, to reactive gases such as oxygen, hydrogen and vapors. The sensitivity of the apparatus is usually in the microgram range, with an accuracy of ±1% and a similar level of precision. The results obtained from TG experiments are subject to a variety of experimental variables, and an understanding of the effects of these is essential to a correct interpretation of the results. TG can be used to study any physical or chemical reaction which gives a mass change, and includes absorption and desorption of gases, sublimation and vaporization, the thermal decomposition of a wide range of materials from inorganic compounds to polymers, the reaction between a gas and a solid, and solid–solid reactions. TG has also been widely used to carry out kinetic studies on solid materials, with the aim of determining the reaction model and the kinetic parameters of activation energy (E) and frequency factor (A). However, considerable care is required in the interpretation of the results obtained.