IMPERMEABLE, ABRADABLE SEAL AND METHOD FOR THE PRODUCTION THEREOF

摘要

Gas turbine engines employ a variety of abradable liners to decrease the clearance between the rotating components and the surrounding casing. There is normally a trade-off between porosity, (and concomitant permeability) and the abradability of the liner material, such that materials with good abradability are permeable to gas flow-resulting in performance losses. Permeability of porous liners is decreased by infiltrating the liner with a low-viscosity liquid containing a metal or metal oxide. After infiltration, the viscosity of the liquid is substantially increased to prevent its egress from the porous liner. Thereafter, the liner is heated at an elevated temperature to drive off the remaining liquid and provide an oxide which blocks the passages and decreases the permeability of the liner.