Water vapor corrosion test using supersonic gas velocities

Testing of the corrosion resistance of environmental barrier coating (EBC) systems is necessary for developing reliable coatings. Unfortunately tests under realistic gas turbine conditions are difficult and expensive. The materials under investigation as well as parts of the test setup have to withstand high temperatures (>= 1200 degrees C), high pressure (up to 30 bar) as well as the corrosive atmosphere (H2O, O-2, NOx). Therefore most lab scale test-rigs focus on simplified test conditions. In this work water vapor corrosion testing of EBCs with a high velocity oxy fuel (HVOF) facility is introduced which combines high temperatures and high gas velocities. It leads to quite high recession rates in short periods of time, which are comparable to results from literature. It was found that high flow velocities can easily compensate low gas pressures. HVOF-testing is a simple and fast way to measure the recession rate of an EBC-system. As proof of concept the recession rates of an oxide/oxide CMC with and without EBC were measured.