High temperature sliding wear testing of materials
High temperature tribological testing often requires the development of complex mechanical setups, that should meet rigorous standards and specific performance metrics. Thus, the development of a state-of-the-art experimental setup to study the reciprocating sliding behaviour of various bulk and coated materials at temperatures that can reach up to 1000 °C is needed, especially for the evaluation of high temperature materials for aeronautical applications.
A macro-load tribological tester was developed at the Materials Engineering Department (MTM) of KULeuven, which allows for the evaluation of the reciprocating sliding behavior of bulk or coated materials at temperatures up to 1000 °C. In particular two different series of heating profiles can be implemented, namely under elevating or isothermal temperatures. The selection of the first methodology was based on the hypothesis that the coefficient of friction of a tribosystem strongly depended on the bulk and surface characteristics of the materials. Indeed, the formation of e.g. an oxide film at the interface of the contacting materials will result in a change of the coefficient of friction, and thus a first indication of the temperature at which this phenomenon took place, will be drawn. Therefore by performing elevating wear tests it is easier to pin point the temperatures at which the progressing phenomena affect the tribological behaviour of the tribosystem and define the temperature limits at which a material can be functional. On the other hand, isothermal tests are used to investigate theinfluence of structural changes and oxide formation of thermally stable systems and provide additional information to the elevating temperature tests. Combination of these profiles is also possible (e.g. cyclic heating).
- A methodology was established to evaluate the effect of temperature on the friction and wear of industrial coated or bulk materials. Different heating profiles can applied to simulate the actual environment of the application.
- Elevating temperature profiles can be used to pin point the temperatures at which the progressing phenomena (e.g. phase transformation, oxidation) affect the tribological behaviour of a tribosystem and define the temperature limits at which a material can be functional.
- Isothermal heating profiles are used to evaluate the tribological behavior of thermally stable systems.