Paste thermal data, select baseline points, and instantly see transitions clearly today. Export reports to CSV or PDF for labs, classes, and audits easily.
Illustrative values for a heating run; paste them into the dataset box.
| X (time or temperature) | Ts | Tr | ΔT = Ts − Tr |
|---|---|---|---|
| 0 | 25 | 25 | 0 |
| 1 | 30 | 29.95 | 0.05 |
| 2 | 40 | 39.7 | 0.3 |
| 3 | 55 | 54.1 | 0.9 |
| 4 | 70 | 68.6 | 1.4 |
| 5 | 85 | 83.2 | 1.8 |
Interpretation note: In DTA, endothermic or exothermic behavior is inferred from the sign of ΔT relative to baseline, and the exact sign convention can vary by instrument wiring.
Differential thermal analysis compares a sample and an inert reference while both follow the same heating program. The instrument reports the differential temperature, ΔT = Ts − Tr, which departs from zero when the sample absorbs or releases heat during a transition.
Common laboratory ramps are 2–20 °C/min over 25–1000 °C, depending on material stability. Slower rates improve resolution of closely spaced events, while faster rates increase throughput but broaden peaks and shift apparent onsets higher. Short holds can stabilize the baseline before a key event.
Real instruments show drift from sensor offsets, contact resistance, and changing heat capacity. A baseline from the pre‑event region helps remove this drift. Averaging the first N points is simple; polynomial baselines can help when drift is curved. In practice, N = 10–50 points is typical.
A transition is often summarized by onset temperature, peak temperature, and end temperature. The onset is detected when the baseline‑corrected ΔT exceeds a threshold above noise, such as about three times the standard deviation of a stable segment. Report results with the heating rate used.
Peak area is proportional to the total heat effect for a calibrated system. With discrete data, trapezoidal integration is robust: Area ≈ Σ 0.5(ΔTcorr,i−1 + ΔTcorr,i)(xi − xi−1). Using temperature as x gives area in °C·°C; using time gives °C·s. Regular sampling reduces numerical error.
To convert area into enthalpy, a calibration constant K is required, usually obtained from a standard with known transition enthalpy (for example, indium). The calculator accepts K and sample mass to output ΔH and ΔH/m for comparisons. Re‑calibrate after major setup changes.
For single‑point checks, enter Ts and Tr directly. For datasets, supply Time–Ts–Tr or Temp–Ts–Tr rows. Keep units consistent; if your instrument outputs millivolts or microvolts, treat ΔT units as those signal units. Note the atmosphere because reactions can add peaks.
DTA indicates thermal events, but identification needs context: atmosphere, crucible type, sample mass, and prior history. Repeat runs, compare with DSC/TGA when available, and document baseline points and thresholds so others can reproduce reported temperatures and areas. Keep heating rate and mass consistent when comparing samples. and always record your chosen sign convention.
ΔT is the differential temperature between sample and reference: Ts − Tr. A non‑zero ΔT indicates the sample is absorbing or releasing heat relative to the reference during the same heating program.
Choose Time–Ts–Tr if your instrument logs time steps, or Temp–Ts–Tr if it logs temperature steps. Use the option that matches your columns so integration and onset detection are consistent.
Use points from a stable region before the event. Ten to fifty points is common, but the best value depends on your sampling rate and noise. Avoid including any pre‑transition curvature or drift spikes.
Start with a threshold slightly above noise, often about three times the standard deviation of ΔT in a quiet region. If you see false triggers, raise it; if true events are missed, lower it cautiously.
After baseline correction, peak area summarizes the total thermal effect of the event. With calibration, area can be converted to enthalpy, enabling comparisons across materials or processing conditions.
You can still compute area and peak metrics, but enthalpy requires a calibration constant K determined from a reference material run under the same setup. Without K, treat results as relative units.
Include the heating rate, atmosphere, sample mass, baseline points, threshold, units, and whether the event is endothermic or exothermic under your sign convention. These details make comparisons and replication credible.
Accurate DTA work needs stable baselines and consistent heating.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.