Aluminium oxide (Al2O3) is characterised by its high melting temperature of 2070°C, which makes it an ideal material for high-temperature applications up to 2000°C. Among other things, it is used in thermal analyses as a reference for melting behaviour, as in the following measurement of aluminium oxide with an STA PT 1600 (TG combined with simultaneous DSC or DTA).
The figure shows a typical DTA curve of Al2O3, in which a strong endothermic peak marks the melting point. The onset point at 2071.2°C and the offset point at 2090.8°C illustrate the beginning and end of the melting process, while the area under the curve represents the heat of fusion, in this case 1022.4 J/g. This is the amorphous phase of corundum, a very inert and stable material that is of central importance in materials science and analysis.
