Abradable hybrid ceramic wall structures
First Claim
1. Heat resistant abradable wall structure having high resistance to erosion, corrosion and oxidation, comprising a support wall having thereon a cellular element comprising partition cell walls forming a multiplicity of cells opening outwardly from said support wall, said support wall and cellular element comprising metal superalloys, a heat-resistant, oxygen barrier, ceramic core layer comprising at least one heat-resistant oxygen barrier, ceramic composition which fills each of said cells to an extent of between about 80% and 90% of their volume and which tapers up to at least the level of the upper edges of said partition cell walls, to provide a ceramic core layer having an uneven outer surface having areas recessed within each of said cells, and an abradable, porous, heat-resistant surface layer which fills the remaining portion of each of said cells and covers said heat resistant layer and said cellular structure, said abradable layer comprising a porous superalloy layer of M'"'"'CrAlY in which M'"'"' is one or more metals selected from the group consisting of nickel, cobalt and iron, and having a thickness, in areas overlying the upper edges of said partition cell walls, of between about 0.01 and 0.06 inch, said abradable layer rendering said cellular structure resistant to erosion, corrosion and oxidation.
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Abstract
Abradable wall structures for high temperature applications, such as in turbine housings and the like. The wall structures comprise a superalloy metal base plate supporting a superalloy metallic cellular structure, the cells of which are filled to a substantial extent with at least one ceramic core material providing high heat resistance, oxygen barrier and low thermal expansion properties. The invention involves the application of a porous or pore-forming surface composition to provide a corrosion-resistant, erosion-resistant abradable outer surface layer, the softness or porosity of which can be tailored to improve the abradability of the wall structure, while imparting oxidation-, corrosion- and erosion-resistance to the structure. The surface layer composition may comprise metal superalloy, ceramic or cermet base compositions containing fugitive or retained inert filler materials.
98 Citations
14 Claims
- 1. Heat resistant abradable wall structure having high resistance to erosion, corrosion and oxidation, comprising a support wall having thereon a cellular element comprising partition cell walls forming a multiplicity of cells opening outwardly from said support wall, said support wall and cellular element comprising metal superalloys, a heat-resistant, oxygen barrier, ceramic core layer comprising at least one heat-resistant oxygen barrier, ceramic composition which fills each of said cells to an extent of between about 80% and 90% of their volume and which tapers up to at least the level of the upper edges of said partition cell walls, to provide a ceramic core layer having an uneven outer surface having areas recessed within each of said cells, and an abradable, porous, heat-resistant surface layer which fills the remaining portion of each of said cells and covers said heat resistant layer and said cellular structure, said abradable layer comprising a porous superalloy layer of M'"'"'CrAlY in which M'"'"' is one or more metals selected from the group consisting of nickel, cobalt and iron, and having a thickness, in areas overlying the upper edges of said partition cell walls, of between about 0.01 and 0.06 inch, said abradable layer rendering said cellular structure resistant to erosion, corrosion and oxidation.
Specification