Development of technologies for the cost-efficient production of HT components and systems

Due to their high resistance to corrosion, temperature and creep, monolithic ceramics and fibre-reinforced ceramics (CMC) are very well suited for use in high-temperature processes. For high-temperature systems, such as heat exchangers, heat accumulators or handling tools, components with complex geometry are required. Components made of high-temperature materials, on the other hand, can usually only be manufactured in simple geometry, such as plates or tubes, at reasonable cost.

Through the development of joining techniques, individual components made of high-temperature materials are to be joined to form components with complex geometries. The focus here is on joining monolithic ceramics and CMC (ceramic-ceramic composites) as well as metal-ceramic composites. Just like the selected materials, the joining must be able to withstand high temperatures.

The joints are designed using FE simulations. Local heating methods (laser and induction heating) and high-temperature furnaces are used for the joining process. The joining parameters are determined by computer simulations of the temperature distribution.

The joining is optimised on sample components:

• Monolithic ceramics e.g. Al₂0₃, SiSiC
• Composite ceramics (CMC) e.g. SiC/SiC, O-CMC
• Light metals e.g. titanium, aluminium

The joints are subjected to the following quality tests:

• Investigation of the mechanical and thermal properties
• Non-destructive testing
• Microstructure analysis and fractography

Joining techniques are used to produce a demonstrator that contributes to the energy efficiency of heat treatment plants.