Performance Analysis of Abradable Coating Systems for Aircraft Gas Turbines

Abradable coating systems in aircraft gas turbines minimize the clearance between rotating blade tips and stationary liners, acting as sealants that improve engine efficiency. In this work, abradable liners made of a nickel‐based superalloy substrate are coated with a CoNiCrAlY bondcoat, an intermediate Y 2 O 3 ‐stabilized ZrO 2 (YSZ) layer, and a MgAl 2 O 4 abradable top layer. The coated systems are evaluated using both thermal gradient cycling and incursion tests designed to replicate real operating conditions. To enhance bonding strength for thicker abradable coatings, laser ablation is applied to the bondcoat and YSZ layer to increase mechanical interlocking between layers. Furthermore, a combined dense and porous microstructure is introduced in the thick MgAl 2 O 4 coating to lower the overall energy release rate while improving toughness near the interface. Three coating configurations are tested: (i) a standard high velocity oxygen fuel (HVOF) sprayed bondcoat with a standard atmospherically plasma sprayed (APS) YSZ/MgAl 2 O 4 double‐layer used as a reference, (ii) a laser‐ablated HVOF bondcoat with a laser‐ablated APS YSZ layer and a standard MgAl 2 O 4 layer, and (iii) a laser‐ablated HVOF bondcoat with a standard APS YSZ layer and a dense/porous MgAl 2 O 4 layer. Both modified liners showed superior incursion performance and no failure after 1500 thermal cycles (125 h at 1390°C).