Thermal analysis extended by means of thermomechanical analysers
Since October 2020, two thermomechanical analysers have been in use at the Meissen Keramik-Institut, namely the Hitachi TMA 7300 and the TMA/SS7300 of SII NanoTechnology Inc. In principle, the devices work like pushrod dilatometers in vertical direction. In contrast to ordinary dilatometers, however, a defined compressive force of maximum 1.47 N (approx. 150 g) can be exerted on the specimen additionally. The load can be constant, linear or sinusoidal. Measurements up to maximum 1,500 °C are possible with a heating rate of 0.01 K/min – 100 K/min.
The method allows the deformation behaviour and/or stability behaviour to be investigated in the high temperature range under increasing or alternating compressive load. Thus, it can be examined, for example, to what extent high-temperature materials subjected to spontaneous forces show a lasting deformation at high temperatures and revert again to their initial state once the force is reduced. In addition, it is possible to determine dilatometric stress-shrinkage curves, coefficients of linear thermal expansion and characteristic temperatures, such as the transformation temperature and dilatometric softening point.