Thermogravimetry of the NiO-Al2O3 system in a hydrogen flow

Thermogravimetry in a hydrogen flow is used to distinguish different forms of NiO-Al₂O₃ bonding at the temperatures of reduction of NiO. The influences of the temperature of preliminary treatment and the component ratio on the shapes of the TG and DTG curves of reduction were represented. By comparison of the results obtained with different weights and with different particle sizes, the influences of diffusion of water vapour in macropores on the characters of TG and DTG curves were studied. Different types of TG and DTG curves of reduction were observed:

1. Curves usual in thermal analysis, whose positions depend on the specimen weight and on the dispersity of the sample.
2. Curves whose position displays almost no change with variations of 1–2 orders the specimen weight.
3. Curves the number of reduction rate peaks in which depend on the experimental conditions.