Ceramic materials are used, for example, for components which can separate pure oxygen from air. The component is a sandwich of three different ceramic layers and its manufacture currently involves a three-stage process. With a new grant from the Danish Council for Independent Research, Technology and Production Sciences, the Fuel Cells and Solid State Chemistry Division at Risø DTU will seek to manufacture complex ceramic components by means of well-known, simple methods. The components can also be used for magnetic refrigerators, cleaning exhaust gases and much else besides.
 | The grant from the Danish Council for Independent Research, Technology and Production Sciences for developing methods for manufacturing functional ceramic components totals DKK 20,112,517.
The project will focus on designing graded components produced by tape casting or extrusion.
There are three main activities:
- Modelling both the design and subsequent sintering in detail which, together with
- experimental studies of micro structures and mechanical properties during sintering will make it possible to optimise design methods. The results will then be used to
- design graded ceramic components with a certain microstructure and shape.
The project will be undertaken jointly by the Fuel Cells and Solid State Chemistry Division (ABF), the Materials Research Division (AFM), DTU Mechanical Engineering, Aarhus University, EMPA in Switzerland, Sandia National Laboratories in the USA, the German Fraunhofer-Institut für Silicatforschung as well as three Danish companies (CoMeTas A/S, Ferroperm Piezoceramics A/S and Topsoe Fuel Cell A/S) which are interested in utilising the results.
See the grant overview from the Danish Council for Independent Research, Technology and Production Sciences (FTP). (in Danish)
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Functional ceramics are ceramic materials which have special electrochemical, electrical or magnetic properties. Functional ceramic materials can be used for countless purposes.
At Risø, by far the biggest application area is the development of ceramic SOFC fuel cells and SOEC electrolysis cells. However, research is also being conducted into using functional ceramics for flue gas purification, magnetic refrigeration and oxygen membranes.
An oxygen membrane can separate atmospheric air into pure oxygen and nitrogen. It consists of a sandwich of three layers of ceramic materials with different properties. The first layer is an electrode where the separation of oxygen and nitrogen starts. The intermediate layer is an electrolyte which allows the oxygen to pass through as ions. The last electrode transforms the oxygen ions into pure oxygen.
“You can imagine an oxygen membrane shaped like a pipe with atmospheric air on the outside and pure oxygen flowing through the hollow in the middle. This is the sort of component we want to be able to make in one go. However, it means that the properties of the ceramic materials must be changed through the component from the outside to the inside, so it is, as it were, built up of three layers, each with its own function,” says Nini Pryds from the Fuel Cells and Solid State Chemistry Division at Risø DTU, who is responsible for the project.
This is the basic idea of the research project. To find ways of varying the relevant properties (e.g. electrical, electromechanical or magnetic) in a controlled fashion along the length of the component. Such multi-material or graded functional components can be manufactured using familiar, simple methods known from the ceramics industry. Methods such as tape casting and extrusion.
“So far we know very little about the processes which determine the properties of the finished component. The aim of our project is therefore to generate the knowledge required to optimise the manufacture of graded ceramic components,“ says Nini Pryds.
The actual outcome of the project will be simple and inexpensive components for using in three promising energy technologies: magnetic refrigeration, oxygen membranes and electromechanical flue gas purification.
The figure shows examples of the different types of ceramic components that Risø wants to manufacture in one go using well-known, simple methods such as tape casting and extrusion. The component on the left and far right could be an oxygen membrane. The two components at the centre could be components for magnetic refrigeration. Here, one end must function in the cold while the other end needs to function in the heat to pump the heat out of our refrigerators.
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