Measurement of material properties at high temperatures requires precision control of the sample temperature. Measurement volumes must be sufficiently large to provide representative material properties, but on the other hand, should not be larger than necessary to facilitate short heating and cooling cycles. For many measurement tasks – especially for homogeneous materials – commercial solutions are already available, which are employed at the Fraunhofer-Center HTL for high-temperature characterization. Furthermore, HTL uses specially developed ThermoOptical Measuring devices to obtain precise data even for heterogeneous materials or otherwise unavailable material properties at high temperatures.
The following thermal, mechanical, electrical, optical and chemical material properties can be measured at high temperatures:
- Temperature/thermal conductivity
- Heat capacity
- Hemispheric and directional emissivity
- Coefficients of thermal expansion
- Thermal shock behaviour
- Temperature change resistance
- Resistance to high-temperature
- Creep behaviour
- Corrosion resistance
- Wetting behaviour
- Impedance characteristics
The device TOM_wave was developed for the measurement of thermal and thermomechanical material behaviour of sample volumes between 10 and 100 ccm. The mechanical high-temperature behaviour is analyzed using the device (see TOM_mech) as well as by using commercially available test equipment. The devices TOM_chem, TOM_imp and TOM_ac are available for the analysis of corrosion behaviour as well as impedance and wetting characteristics. Conventional thermal analyses are performed using commercial devices for differential thermal analysis, thermogravimetry (coupled with mass spectrometry), laser flash analysis and push rod dilatometry.