Examples

1. TGA of alumininium hydroxide

The Fig. 10A shows a typical TGA profile for aluminium hydroxide prepared by precipitation method in nitrogen flow at heating rate of 10 K/min. The weight loss corresponds to conversion of aluminium hydroxide to aluminium oxide by removal of water.

2. TGA of activated carbon

The Fig. 8B shows a typical TGA profile for activated carbon in nitrogen flow at a heating rate of 10 K/min. The initial weight loss at 100⁰C is due to removal of moisture. Since the carrier gas is inert, there is no further significant change in the weight of the sample.

Fig. 8. Typical TGA profile for (A) aluminum hydroxide (B) activated carbon

Differential Thermal Analysis (DTA)

DTA consists of heating a sample and reference material at the same rate and monitoring the temperature difference between the sample and reference. In this method, the sample is heated along with a reference standard under identical thermal conditions in the same oven. The temperature difference between the sample and reference substance is monitored during the period of heating. As the samples undergo any changes in state, the latent heat of transition will be absorbed/ evolved and the temperature of the sample will differ from that of the reference material. This difference in temperature is recorded. Hence, any change in state can be detected along with the temperature at which it occurs.

Fig. 9. Schematic diagram for differential thermal analysis technique.