Abstract: A seal (48) between first and second relatively rotatable members (26,28). The seal comprises an abradable material on at least one of the relatively rotatable members (26,28). The abradable material comprises an open cell metallic foam (60) and polymeric films (64) closing the cells (62) of the metallic foam (60). The seal (48) is used between compressor rotor blades (26) and a stator casing (28) of a gas turbine engine (10). The seal (48) combines the sealing properties of a closed cell metallic foam with the abradability and manufacturing control of open cell metallic foam.

Abstract: A method of repairing a damaged abradable coating (48) on a surface (46) of a shroud (44) in an assembled gas turbine engine (10) comprises inserting a boroscope (60) through an aperture (52) in the casing (50) of the compressor (26) of the gas turbine engine (10). The boroscope (60) is arranged to carry a conduit (62). The boroscope (60) and hence the conduit (62) are directed to the damaged abradable coating (48) on the surface (46) of the shroud (44). A liquid abradable glue (64) is supplied through the conduit (62) and the liquid abradable glue (64) is directed onto the surface (46) of the shroud (44) in the compressor (26) of the gas turbine engine (10) to repair the damaged abradable coating (48).

Abstract: A seal (48) between first and second relatively rotatable members (26,28). The seal comprises an abradable material on at least one of the relatively rotatable members (26,28). The abradable material comprises an open cell metallic foam (60) and polymeric films (64) closing the cells (62) of the metallic foam (60). The seal (48) is used between compressor rotor blades (26) and a stator casing (28) of a gas turbine engine (10). The seal (48) combines the sealing properties of a closed cell metallic foam with the abradability and manufacturing control of open cell metallic foam.