We are very proud to announce that our latest collaboration with National Physical Laboratory and Cranfield University on damage mechanisms in impact and erosion of thermal barrier coatings has just been published in Surface and Coatings Technology.
Developing improved thermal barrier coating (TBC) systems is key to enabling higher engine operating temperatures that will increase the efficiency of gas turbines, saving fuel and reducing CO2 emissions.
The NanoTest impact tests were able to replicate the deformation mechanisms and surface morphology in the erosion tests and reproduce differences in erosion rate between TBCs, although there was more compaction in the impact tests, which may be due to differences in erodent/probe geometry. Densification below impact craters on 7YSZ and sub-surface cracking between the dense layer and the un-densified columns were revealed by focused ion beam milling. Cracking over several columns and break-up of the columnar structure was observed in the impact and erosion tests on GZO. Clear differences in TBC erosion rate, with GZO being much less resistant to erosion, were replicated in the cyclic and statistically distributed micro-impact tests.
The major erosion damage mechanisms were reproduced in the cyclic and statistically distributed micro-impact tests, so these should have considerable potential as screening tests for evaluating promising erosion-resistant TBC compositions.
Many thanks to Hannah Zhang, Mark Gee, Luis Isern, John Nicholls, Christine Chalk, Diane Johnson, Koldo Almandoz Forcen, and our own Stephen Goodes for all their hard work with developing this test technique.
Access the full paper here