CD Laboratory for Combinatorial oxide chemistry

The thin oxide layer surrounding alloys is often decisive for the industrial applicability of the alloy. Here, the properties of these layers and their interaction with the alloys are investigated experimentally.

Metals and Alloys usually occur in compounds in the earth's crust, which are often oxygen compounds. In industrial production, the oxygen is laboriously removed from the material, after which they react with oxygen again, but only on the surface: they are coated with a thin layer of oxides. This oxide layer prevents stainless steel from rusting, for example, or changes the ferromagnetic behaviour of transformer components.

There is an almost infinite number of variables in the industrial production process for alloys: Which metals are used in which ratio, how pressure and temperature are set, how much time is allowed to pass, etc.?

In this laboratory, the search is on for the ideal alloy for a specific purpose. For example, oxides often cause problems when rolling a material: they are rolled in and damage the paint - are there combinations that achieve a better result? Other alloys already have good properties but are expensive - are there alloys with the same properties but which are cheaper?

Experiments are used to answer these and other questions: a specially developed device (called CALMAR) creates suitable samples and analyses their properties under various conditions. These samples are called "material libraries" and show, for example, a material gradient in a very small space. In this way, a large amount of data can be obtained with a single analysis. In order to make these extensive data sets usable, the necessary computerisation is also being worked on here. Particular attention is paid to the following properties of oxide layers:

- Control of the reaction speed with the environment, for example slower rusting

- Functional oxides, for example for storing the energy of sunlight in chemical compounds

- Effects on ferromagnetic behaviour, for example to avoid heat losses in transformers.

With the experimental approach, previously unknown effects can also be discovered if a combination of substances behaves differently than expected. This makes it possible to find materials that cannot be found by modelling alone - at the same time, knowledge of unexpected effects also leads to a deeper understanding of matter.