Patent ID: 8187717
Filing Date: 2012-05-29
Classification: C04B,C23C,F01D,Y02T,Y10T

Abstract:
1. A high-purity abradable seal coating system comprising: an abradable top coat formed of a composition comprising about 70-99 weight percent of a ceramic material and about 1-30 weight percent of a removable placeholder material, said ceramic material consisting essentially of about 4 to 20 weight percent of a stabilizer of one or more rare earth oxides, and a balance of at least one of zirconia (ZrO said removable placeholder material comprising an organic powder material or an inorganic powder material, and said removable placeholder material being structured and arranged to be burned out subsequent to deposition of the coating material; and one of an oxidation and/or hot corrosion resistant MCrAlY or MAI or MCr bond coat, an intermediate zirconia- or hafnia-stabilized ceramic, and an intermediate cermet of an oxidation-resistant MCrAlY and a high-purity zirconia/hafnia ceramic, wherein the abradable top coat is sprayed over the bond coat, the zirconia- or hafnia-stabilized ceramic, or the intermediate cermet, wherein the sprayed abradable top coat includes the ceramic material and the removable placeholder material and is sprayed using a thermal spray process at pressures between 1 Pa and 1 MPa, so as to form a stream of molten and/or semi-molten droplets that build up a coating of frozen lamellar splats subsequent to impact, and wherein the removable placeholder material is removed from the sprayed abradable top coat to make a resulting sprayed abradable top coat having a structure including a ceramic matrix, porosity, and micro cracks.