Differential Scanning Calorimetery (DSC) and Differential Thermal Analysis (DTA)
Differential Scanning Calorimetry (DSC) and Differential Thermal Analysis (DTA) measure energetic effects such as melting, crystallization and other phase transitions by monitoring small temperature differences between the sample and an empty crucible on the reference position. The DTA is used to determine only the transition temperatures, whereas in the DSC the temperature difference is converted into energy units via calibrations with a sapphire standard and pure metal melting standards and the transition enthalpies can also be reliably determined. A good DSC instrument with a stable and repeatable baseline can be used for specific heat capacity measurements with an accuracy of about 3%. The figure below shows the DSC curve for a steel sample in which the Curie transition (peak at 762.9˚C) and the melting at 1535.5˚C are clearly visible.
Instrument specifications and sample requirements:
Ideal Sample Weight: 10 – 50 mg
Temperature Accuracy: +/- 1 ˚C
Heat Flow Accuracy: +/- 2%
Specific Heat Capacity Accuracy: +/- 3%
Recommended Heating rate*: 20˚C /min
Temperature Range: Ambient to 1600 ˚C
* Lower and higher heating rates are also possible and should be discussed with the lab for each specific set of samples.