Faster repair for turbines
With little effort, a new laser method creates protective ceramic structures.
They can take a lot: thin ceramic layers protect components in aircraft turbines or power plants from the hot temperatures of around 1,500 degrees Celsius at which paraffin or natural gas is burnt. After thousands of hours of operation, however, ageing processes can damage the coatings. Repairs are complex and expensive. In the future, with a new method from Jülich, small damages could be repaired easily and quickly.
The method developed by Dr. Christoph Vorkötter, Dr. Daniel Emil Mack and Martin Tandler from the Institute of Energy and Climate Research (IEK-1) uses a laser-cladding-based additive manufacturing technique. “We use an argon gas jet to blow ceramic powder onto a sample and melt the powder with a laser beam,” Vorkötter explains. In the process, the laser beam and the powder feed move away from the sample surface at a speed of five millimetres per second. In this way, microcolumns a few millimetres in size form in a close pattern. “Column structures like these remain stable even at high temperatures and can withstand frequent temperature changes, such as those that occur in gas turbines. We can produce the columns in different dimensions and arrange them flexibly,” says Vorkötter.
Sample with microcolumns
Unlike other coating methods for ceramics, the new method does not require a vacuum. Due to its low energy demand, it could also be applied directly at the site of a gas turbine. The researchers have already filed a patent application for it and are now looking for partners from industry.
Photo: Forschungszentrum Jülich/Hiltrud Moitroux, frank_peters/Shutterstock.com