Principle:

Differential thermal analysis is a methods in that the temperature  of the substance under investigation is compared along with the temperature  of a thermally inert  material like as  α-alumina and is recorded  along with furnace temperature as the substance is cooled or heated  at a predetermined  uniform rate. The range of temperature measurable in the course of DTA is much larger than TG determination. Therefore, during TG, pure fusion reactions, glass transition, crystalline transition, and crystallization and solid state reactions along with no volatile product would not be denoted since they give no modification in mass of the specimen. Therefore, these changes are denoted during DTA through endothermal or exothermal departure from the base line. Because DTA is a dynamic method, it is necessary that all aspects of the technique be standardized in order to acquire reproducible results. These involve pretreatment of specimen, particle size and packing specimen and dilution of the specimen and nature of the inert diluent.

A principle of technique consists in measuring the modification in temperature related along with physical or chemical changes during the gradual heating of the substance.

Thermal changes because of fusion, boiling, crystalline structure inversions, dissociation or decomposition reactions, oxidation and reduction reactions, destruction of crystalline lattice structure and other chemical reactions are commonly accompanied through an appreciable increase or fall in temperature. Therefore, all these are accounted in DTA. Commonly speaking, phase transitions, dehydration, reduction and a few decomposition reactions generate endothermic effects while crystallization, oxidation and a few decomposition reactions generates exothermic effects.

Within DTA a sample of material under investigation (specimen) is placed through the side of thermally inert material (the reference sample) commonly calacite or α- alumina in appropriate sample block or holder. The temperature difference among the two is continuously recorded as they are heated. The block is heated within an electric furnace that is. both are heated under identical conditions.