Differential Thermal Analysis measures the relationship between temperature and heat flow within a material in relation to thermal transitions and has a wide range of applications, especially in materials development, performance testing and quality control.
Material properties such as glass transition temperature, cold crystallization, phase transition, melting, crystallization, product stability, curing/crosslinking, oxidation induction period, etc., are all areas of study for thermal analysis.
Basic principle of differential thermal analysis: A technique for measuring the temperature difference between a substance and a reference material over time or temperature under programmed temperature control. When a physical or chemical change occurs in the specimen during heating, the heat released or absorbed makes the temperature of the specimen higher or lower than the temperature of the reference material, and the exothermic or heat-absorbing peak is obtained on the differential heat curve.
Main measurement functions: glass transition, crystallization, melting, phase change temperature, latent heat of phase change, oxidation and decomposition processes, etc. The reference material should be selected as an inert material, i.e. a material that does not produce any thermal effect under the measured conditions, e.g. A12O3, silicone oil, etc.
When the temperature rises to a certain temperature, the specimen undergoes a thermal effect transformation, such as: phase transition, dissolution, crystal structure changes, oxidation or decomposition, etc., the temperature of the specimen and the temperature of the reference is no longer equal, the differential thermocouple has an electrical signal output, then the curve of the recorded temperature difference deviates from the baseline. the curve of DT with temperature (or time) is called the differential thermal curve (DTA curve).
Factors affecting the DTA curve.
(1) the rate of temperature rise, generally the greater the rate of temperature rise, the higher the peak temperature, the larger and sharper the peak shape.
2) the atmosphere in the furnace.
3) sample supporter.
4) thermocouple position.
(5) thermocouple contact point.
On the DTA curve:
1) The temperature of the thermal effect transition can be determined by the position of the peak;
(2) the area of the peak to determine the size of the thermal effect;
(3) the shape of the peak can be understood by the characteristics of the process kinetics.
The crucible to be used for thermal analysis.
Generally, metallic aluminum crucibles for thermal analysis as well as alumina and zirconia crucibles for thermal analysis will be used. However, because of their relatively high temperatures, alumina crucibles are used more often.
Ceramic Parts India Inc. is a professional supplier of crucibles for thermal analysis(TA, PerkinElmer, Netzsch, Shimadzu, Mettler, Netzsch, Setaram, Linseis), please feel free to contact us if you need thermal analysis consumables.