I started my thermal analysis using DSC, but the thermocouple was destroyed, hence I thought of using the DTA that is available.
My question is, can i do my calculations such as calculating the enthalpy of formation, the calculation of the amount of phases formed ... using the DTA and get the same results as those of the DSC.
Thank you very much.
I wouldn't say that DSC and DTA are identical - many of DSC instruments use more elaborate measurement methods, but I agree with Atul that DTA is more qualitative. Nevertheless it can be used for quite accurate quantitative measurements, specifically for determining integral effects like enthalpy of formation, but it requires careful calibration. In DTA case sensitivity strongly depends on experiment condition (type of crucible, atmosphere, amount and position of the sample in the crucible), therefore calibration must be made under the conditions that are as close as possible to ones of experiment.
Yes, both techniques are identical but DTA is more qualitative though. Check this paper:
http://www.sciencedirect.com/science/article/pii/S0040603199001069
I wouldn't say that DSC and DTA are identical - many of DSC instruments use more elaborate measurement methods, but I agree with Atul that DTA is more qualitative. Nevertheless it can be used for quite accurate quantitative measurements, specifically for determining integral effects like enthalpy of formation, but it requires careful calibration. In DTA case sensitivity strongly depends on experiment condition (type of crucible, atmosphere, amount and position of the sample in the crucible), therefore calibration must be made under the conditions that are as close as possible to ones of experiment.
Although the principles of the measurement for the heat-flux DSC and DTA are similar, the constructions of DTA and DSC are different. DTA construction enables the heat transfer by the purge gas and the irradiation. Hence, application temperatures of DTA are higher, it is advisable to use DTA over 200 degC. The construction of DSC enables the heat transfer by conduction so that the application temperature range is from -130 degC (-170 degC for Perkin-Elmer) up to 600-800 degC. There are companies declaring to produce high-temperature DSC. In fact, that is just DTA needed a very thorough calibration.
As has been said by previous contributors, DTA is just a semi-quantitative method. Due to the heat transfer by irradiation, the signal depends, inter alia, on the emissivity of the sample. It is quite difficult and laborious to get reliable quantitative values of enthalpies and heat capacities from DTA measurements. DTA is OK for the determination of characteristic temperatures.
The important thing is firstly to understand which instrument is ment under DSC. There are two types: Heat-Flux DSC and Power Compensating (true) DSC. Power compensating DSC has two heaters. The differential signal is then the power difference required to keep the temperatures of sample and reference identical during defined temperature ramp. The signal is then in watts per unit sample mass. In difference HF-DSC has one heater and it looks similar to DTA. But still it looks only from the first glance similar to DTA. If we look on the detectos used in HF-DSC and DTA, then in case of DTA we see only two theromcouples each one has legs lets say A and B. The differential signa will be obtained by shorting legs B and measurement between legs A. In case of HF-DSC there is in addition connecting metal strip which is used as an active measuring element and is A as well. Then difference signal is measured between legs B and B. So in case of HF-DSC the whole surface of the "plate" into which we put crucible can be working as a detector. You can find more full information about what is what in NIST Practice Guide "DTA and Heat-flux DSC measurements of alloy melting and freezing"/. WJ Boettinger, UK Kattner, K-W Moon and JH Perezko.
Dear Bendoumia,
DTA is based on the temperature difference while DSC is based on the heat flow difference. Differential thermal analysis (DTA) is suited for the determination of characteristic temperatures, while differential scanning calorimetry (DSC) additionally allows for the determination of caloric values such as the heat of fusion or heat of crystallisation. This can be done with two different measuring techniques: heat-flux differential scanning calorimetry or power-compensated differential scanning calorimetry.
DSC and DTA are both used in measuring a glass transition, phase changes, purity evaporation, melting, purity crystallization, sublimation, polymerization, heat capacity, compatibility, pyrolysis, etc.
Hope this helping
Have a very good day
The NIST guide "DTA and Heat-flux DSC measurements of alloy melting and freezing" mentioned by Alexandra Khvan is available on ResearchGate or can be found at
From the point of view of fundamental science DSC allows us to get a lot of information for the phase alloys as phase fractions and the transition from a configuration point of the two-phase to single-phase state occur jumps heat. The latter provides information on the second derivative of the Gibbs energy of the composition in the vicinity of one thing - the two-phase state diagrams at the border at which the specific heat jump for both binary and ternary alloys.
However, the measurement by the use of DSC equipment requires highly qualified researchers more and more careful work.
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