Patent ID: 8876466

Claim:
A seal between a first member and a second member, the first member being stationary in use and the second member being movable relative to the first member in use, the seal comprising a liner attached to the first member, the liner being abraded by the second member, the abradable liner comprising a metallic, open porous structure having a plurality of sub-layers of various pore size, wherein the plurality of sub-layers includes an outer laver, a mid-layer and an inner layer, and: the outer layer is adjacent the second member in use and has a smaller pore size than the inner layer and the mid-layer, the mid-layer is between the inner layer and the outer layer and has a larger pore size than the inner layer and the outer layer, and the inner layer joins the mid-layer to the first member, the inner layer having a pore size between that of the outer layer and the mid-layer.