High-Temperature Corrosion Lab
The lab offers various experimental and modelling methods for evaluating various high-temperature oxidation and corrosion phenomena with different types of metallic alloys and coating systems.
Determination of corrosion kinetics is possible in a variety of atmospheres, including wet gases up to 1400 °C with an accuracy of 1µg. Continuous mass change measurements allow evaluation of the exact kinetics parameters, such as parabolic rate constants. The thermogravimetry can be combined with mass spectrometry to study reactions involving volatile products.
To simulate operating conditions in applications such as gas-turbines or aircraft engines thermal cyclic tests are performed in automated furnaces with rapid heating and cooling. The cooling is achieved by pressurized air allowing an average rate of 250 K/min to be reached. The cyclic oxidation can be performed at temperatures up to 1150 °C in various environments, e.g. containing H2O, CO2 or SO2.
Corrosion induced by deposits and liquids
Various deposits compositions can be applied using brushing method to simulate e.g. hot corrosion occurring in aircraft engines. The test gas compositions can also be adjusted to induce reactions in the deposits typically occurring under the service conditions
Corrosion under fast flowing gas conditions
In a number of applications, fast flowing gases result in accelerated damage of the materials due to formation of volatile reaction products. A custom-based facility was built to study such reactions with velocities up to 6 m/s and temperatures up to 1100 °C in wet environments.
Tests are performed in hot granulate beds to study oxidation-erosion interaction e.g. in concentrated solar power (CSP) plants using ceramic particles as a heat-transfer medium. Velocities up to 60 mm/s at temperatures up to 900°C can be reached.
To study chemical compositions of the formed oxide scales, Glow Discharge Optical Emission Spectroscopy (GD-OES) can be used. Analysis of metal and non-metal elements including C, B, N, S is possible. Concentration profiles calculated from the GD-OES data can be used for determining various phenonema including incorporation of minor elements into the oxide scales as well as internal reaction processes such as oxidation, nitridation and sulphidation.
This type of analysis is similar to GD-OES, however, it allows measurements of element isotopes. This offers the possibility to study reaction mechanisms by using tracer gases, such as 18O2, H218O.
Raman spectroscopy is used for phase analysis of corrosion products and for stress measurements in the oxide scales, e.g. those based on alpha alumina. The analysis has a high lateral resolution of approximately 1 µm and is non-destructive.
Modeling of degradation induced by oxidation and corrosion. Several customized approaches are available to simulate e.g. oxide-scale growth, lifetime of components limited by oxidation-induced depletion of alloying elements and degradation of coatings due to combined effect of oxidation and interdiffusion.