| abstract |
An abradable seal material suitable for high temperature application in turbomachinery comprising a sintered mat of (1) randomly disposed fine metal fibers, or (2) fine metal powders or (3) both fibers and powders. The metal fiber and powder are composed of an alloy consisting essentially of I, Al, Cr, II, or I, Al, Cr, III, wherein I is at least one member of the group Fe, Co, Ni, and Co plus Ni, II is a member of the group consisting of Y, Sc and Rare Earths, and III is at least one member of the group consisting of Si, Hf, Zr, Cb, and Ta. The exposed surfaces of the fibers and powder forming the seal are protected against oxidation at high temperatures by a coating of Al2O3 which is formed on the substrate. Said substrate has an Al content of at least 4% to replace spalled Al2O3 and for "healing" any Al2O3 scale fractures. |