A thick abradable YSZ coating for turbine section seals is described. The system is comprised of a MCrAlY bondcoat, an inner layer of vertically segmented YSZ and a top layer of ultra-low density YSZ. The coating is produced by the thermal spray process. Higher thermal shock resistance was obtained by designing an inner layer of vertically segmented YSZ. High abradability was obtained by having an ultra-low density YSZ top layer. The effects of top layer density on abradability and erosion resistance are described. In the abradability test, bare Inconel 738 blade tip simulator substrates and tips coated with either dense, vertically segmented Zircoat~(TM) YSZ by the plasma spray process or cubic boron nitride abrasives in a NiCoCrAlY electroplated matrix were used.
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