Differential thermal analysis (DTA) measures the temperature difference between a sample and a reference material as both are heated. The apparatus consists of a sample holder with thermocouples, a furnace, temperature programmer, and recording system. The sample and reference are placed in identical cavities in a heating block within an oven. Thermocouples contact each to measure any temperature difference. Changes appear as endothermic or exothermic curves on a graph. DTA allows accurate determination of transition temperatures and is highly sensitive even at very high temperatures.

1. Instrumentation of DTA
Maheen Zahra
(1300143)
BS IV (8th)

2. Contents
• Differential thermal analysis
• Apparatus
• Procedure
• Graphical representation
• Advantage of DTA

3. Differential thermal analysis
In Differential Thermal Analysis, the
temperature difference that develops between a
sample and an in reference material is
measured, when both are subjected to identical
heat treatments.

5. INSTRUMENTATION

7. APPARATUS
1.Sample holder comprising thermocouples,
sample containers and a ceramic or metallic
block.
2.Furnace.
3.Temperature programmer
4.Recording system

8. Procedure
• Heart of the analysis – heating block
• Identical pair of cavities for the sample, ref.
material
• Whole unit is set in an oven- control pressure
• Thermocouple is place directly in contact with
the sample and another in contact with the
reference

9. • Temperature of the block is raised, the
temperature of the sample & reference follow
• Zero temp. difference – no physical or
chemical change
• If any reaction – difference in ∆T

11. Graphical Representation

12. NOTE..
• Sharp Endothermic–changes in crystallinity or
fusion Broad endotherms-dehydration
reaction Physical changes usually result in
endothermic curves Chemical reactions are
exothermic

13. • Sharp endotherm: crystalline rearrangemets,
fusion, solid state transition
• Broader endotherm: dehydration, melting of
polymers, slow reactions
• Narrow exotherm: crystallization
• Sharp exotherm: phase change

14. Advantage of DTA
• Instruments can be used at very high
temperatures
• instruments are highly sensitive
•characteristic transition or reaction
temperatures can be accurately determined.

15. REFERENCES
• https://www.slideshare.net/WilwinEdara/dsc-
and-dta
• https://www.phase-
trans.msm.cam.ac.uk/2002/Thermal1.pdf
• https://www.slideshare.net/shaisejacob/differ
ential-thermal-analysis-dta-ppt

16. • https://www.slideshare.net/KhawarYaqoob/di
fferential-thermal-analysis-61206721
• https://www.slideshare.net/sureshselvaraj108
/differential-thermal-analysis