Ceramic Materials Lab
The following characterization methods are available to assess the mechanical behavior of ceramic materials, aiming towards the deep understanding of the relationship between mechanical and microstructural features.
INSTRON testing machines
Four testing machines, equipped with high-temperature furnaces, are available. They are equipped with linear variable differential transformers to measure the deformation as a function of applied load and time. For loading ranges up to 10 KN, temperatures up to 1400 °C for experiments in air and up to 1000 °C for experiments under different application-relevant atmospheres (H2/Ar, N2, vacuum) can be perforemed. Typically elastic behavior, fracture stresses or creep behavior are the focus of the experiments, where ceramic jigs permit a transfer of a compressive to bending situation where appropriate. A long-distance microscope permits the observation of the specimens during the test in the microscale.
An in-house developed torsion tester, equipped with a horizontal furnace, permits a characterization of the application-relevant loading situation of joining materials up to 1000 °C in air. Rotation speed and torque can be varied to determine relevant shear stresses.
Impulse excitation tester
The elastic modulus, shear modulus and Poisson's ratio of ceramic materials can be assessed via a commercial impulse excitation tester (Grindosonic, Lemmens KG) up to 1200 °C under different application-relevant atmospheres (air, H2/Ar, N2, vacuum) on the basis of the specimens' resonance frequency. Different specimen shapes can be tested. In addition, the damping behavior of the signal is obtained, permitting insight into non-elastic processes.
An optical dilatometer (Mitsura) permit an automatic, contact free, assessment of the thermal expansion and curvature change of thin specimens up to a temperature of 1000 °C.