Thermogravimetric Analysis (TGA)
Introduction:
Thermogravimetric Analysis (TGA) is a technique in the field of thermal analysis and is one of the most commonly used methods for material analysis. In this method, changes in the sample’s weight due to temperature variations are recorded and presented as a graph. The results of this analysis can be used to measure the thermal stability of materials and provide valuable information such as moisture content, crystallinity, phase transition temperatures, or reaction points.
Thermal analysis techniques like TGA (Thermogravimetric Analysis), DTA (Differential Thermal Analysis), and DSC (Differential Scanning Calorimetry) are important tools in studying material properties. These techniques are used to understand the physical and chemical changes that occur in materials when exposed to temperature variations, helping to assess material stability, thermal properties, and behavior in various applications.
Working Principle:
TGA is a technique used to evaluate the changes in the chemical and physical behavior of materials when subjected to temperature changes. During the TGA test, the sample is placed inside a crucible made of alumina or platinum, which is mounted in a furnace equipped with a sensitive balance to measure weight.
The furnace can precisely control the temperature, allowing the sample to be heated at a defined rate, maintained at a constant temperature, or cooled gradually to room temperature. This setup allows the study of weight changes in the sample due to temperature variations.
Factors affecting changes in the sample’s mass include moisture loss, presence of crystallization water, emission of volatile compounds, combustion of organic materials in the presence of air, and processes like thermal decomposition and oxidation. These factors play a vital role in understanding the thermal and physical properties of the studied materials.
Measurement Benefits:
1. Measurement of moisture, crystallization water, and volatile compounds in the sample, and monitoring weight changes.
2. Studying thermal stability in air or inert gas environments and obtaining information about weight stability.
3. Identifying weight loss stages, temperature conditions of the sample, and analyzing thermal stability.
4. Studying transformation temperatures in alloys, metallic materials, and organic substances.
5. Studying oxidation degree and oxidation rate at different temperatures.
Result Interpretation:
1. Residual Weight: Shows the remaining weight after heating, providing insight into material stability at high temperatures.
2. Rate of Weight Loss: May indicate chemical reactions such as decomposition or oxidation.
3. Thermal Points: Help determine the temperatures at which reactions occur.