scispace - formally typeset
Search or ask a question
Patent

Use of high temperature insulation for ceramic matrix composites in gas turbines

TL;DR: In this article, a ceramic composition for insulating components, made of ceramic matrix composites, of gas turbines is provided, which comprises a plurality of hollow oxide-based spheres of various dimensions, a phosphate binder, and at least one oxide filler powder, whereby the binder partially fills gaps between the spheres and the filler powders.
Abstract: A ceramic composition for insulating components, made of ceramic matrix composites, of gas turbines is provided. The composition comprises a plurality of hollow oxide-based spheres of various dimensions, a phosphate binder, and at least one oxide filler powder, whereby the phosphate binder partially fills gaps between the spheres and the filler powders. The spheres are situated in the phosphate binder and the filler powders such that each sphere is in contact with at least one other sphere and the arrangement of spheres is such that the composition is dimensionally stable and chemically stable at a temperature of approximately 1600 °C. A stationary vane of a gas turbine comprising the composition of the present invention bonded to the outer surface of the vane is provided. A combustor comprising the composition bonded to the inner surface of the combustor is provided. A transition duct comprising the insulating coating bonded to the inner surface of the transition is provided. Because of abradable properties of the composition, a gas turbine blade tip seal comprising the composition also is provided. The composition is bonded to the inside surface of a shroud so that a blade tip carves grooves in the composition so as to create a customized seal for the turbine blade tip.
Citations
More filters
Patent
17 Sep 2002
TL;DR: In this paper, a hybrid ceramic structure is proposed for high temperature environments such as in gas turbines, which is made from an insulating layer of porous ceramic that is thermally stable at temperatures up to 1700 C bonded to a high mechanical strength structural layer of denser ceramic, where optional high temperature resistant adhesive can bond the layers together.
Abstract: A hybrid ceramic structure (10), for use in high temperature environments such as in gas turbines, is made from an insulating layer (12) of porous ceramic that is thermally stable at temperatures up to 1700 C bonded to a high mechanical strength structural layer (8) of denser ceramic that is thermally stable at temperatures up to 1200 C, where optional high temperature resistant adhesive (9) can bond the layers together, where optional cooling ducts (11) can be present in the structural layer and where hot gas (14) can contact the insulating layer (12) and cold gas (15) can contact the structural layer (8).

185 citations

Patent
21 Jan 2005
TL;DR: In this paper, a thermal/environmental barrier coating (T/EBC) system is proposed for Si-containing materials, particularly Si-based composites used to produce articles exposed to high temperatures.
Abstract: A coating system (14) for Si-containing materials, particularly Si-based composites used to produce articles (10) exposed to high temperatures. The coating system (14) is a compositionally-graded thermal/environmental barrier coating (T/EBC) system (14) that includes an intermediate layer (24) containing yttria-stabilized hafnia (YSHf) and mullite, alumina and/or an aluminosilicate, which is used in combination with an inner layer (22) between a Si-containing substrate (12) and the intermediate layer (24) and a thermal-insulating top coat (18) overlying the intermediate layer (24). The intermediate layer (24) provides environmental protection to the silicon-containing substrate (12), and has a coefficient of thermal expansion between that of the top coat (18) and that of the inner layer (22) so as to serve as a transition layer therebetween. The intermediate layer (24) is particular well suited for use in combination with an inner layer (22) of an alkaline earth metal aluminosilicate (such as BSAS) and a top coat (18) formed of YSZ or YSHf.

156 citations

Patent
16 May 2003
TL;DR: In this article, a hybrid vane for a gas turbine engine having a ceramic matrix composite (CMC) airfoil member bonded to a substantially solid core member is proposed.
Abstract: A hybrid vane ( 50 ) for a gas turbine engine having a ceramic matrix composite (CMC) airfoil member ( 52 ) bonded to a substantially solid core member ( 54 ). The airfoil member and core member are cooled by a cooling fluid ( 58 ) passing through cooling passages ( 56 ) formed in the core member. The airfoil member is cooled by conductive heat transfer through the bond (( 70 ) between the core member and the airfoil member and by convective heat transfer at the surface directly exposed to the cooling fluid. A layer of insulation ( 72 ) bonded to the external surface of the airfoil member provides both the desired outer aerodynamic contour and reduces the amount of cooling fluid required to maintain the structural integrity of the airfoil member. Each member of the hybrid vane is formulated to have a coefficient of thermal expansion and elastic modulus that will minimize thermal stress during fabrication and during turbine engine operation.

152 citations

Patent
09 Sep 2002
TL;DR: In this article, the gap between the CMC member and the support member is kept purposefully small to limit the stress developed in the material when it is deflected against the support by the force of a rubbing blade tip.
Abstract: A ceramic matrix composite (CMC) component for a combustion turbine engine ( 10 ). A blade shroud assembly ( 30 ) may be formed to include a CMC member ( 32 ) supported from a metal support member ( 32 ). The CMC member includes arcuate portions ( 50, 52 ) shaped to surround extending portions ( 46, 48 ) of the support member to insulate the metal support member from hot combustion gas ( 16 ). The use of a low thermal conductivity CMC material allows the metal support member to be in direct contact with the CMC material. The gap ( 42 ) between the CMC member and the support member is kept purposefully small to limit the stress developed in the CMC member when it is deflected against the support member by the force of a rubbing blade tip ( 14 ). Changes in the gap dimension resulting from differential thermal growth may be regulated by selecting an angle (A) of a tapered slot ( 76 ) defined by the arcuate portion.

146 citations

Patent
14 May 2003
TL;DR: In this paper, a ceramic matrix composite material (CMC) vane for a gas turbine engine was proposed, where the airfoil member and the platform member are formed separately and are then bonded together to form an integral vane component.
Abstract: A ceramic matrix composite material (CMC) vane for a gas turbine engine wherein the airfoil member (12) and the platform member (14) are formed separately and are then bonded together to form an integral vane component (10). Airfoil member and the platform member may be bonded together by an adhesive (20) after being fully cured. Alternatively, respective joint surfaces (16,18) of the green body state airfoil member and platform member may be co-fired together to form a sinter bond (30). A mechanical fastener (38) and/or a CMC doubter (42) may be utilized to reinforce the bonded joint (40). A matrix infiltration process (50) may be used to create or to further strengthen the bond.

139 citations

References
More filters
Patent
11 Feb 1986
TL;DR: In this article, a reinforced composite structure consisting of a heat resistant chemically-bonded layer of a ceramic composition mechanically attached to a metallic substrate is presented, which includes a metallic anchoring matrix characterized by a plurality of spatially and cooperably arranged reinforcing elements.
Abstract: A reinforced composite structure is disclosed comprising a heat resistant chemically-bonded layer of a ceramic composition mechanically attached to a metallic substrate. The structure includes a metallic anchoring matrix characterized by a plurality of spatially and cooperably arranged reinforcing elements, the matrix being attached to the substrate and projecting from the surface thereof with the spatially arranged reinforcing elements of the matrix collectively defining a ceramic-occupiable zone of finite thickness adjacent to and following the surface configuration of said substrate, the zone having at least confined therein the heat resistant chemically-bonded ceramic in intimate contact with the reinforcing elements. A method for fabricating said composite structure is also disclosed.

151 citations

Patent
28 Jul 1980
TL;DR: An abradable ceramic seal coating on at least one of a pair of members having relative rotational movement is described in this paper, the coating being formed of stabilized zirconia which is codeposited with a thermally decomposable organic powder.
Abstract: An abradable ceramic seal coating on at least one of a pair of members having relative rotational movement, the coating being formed of stabilized zirconia which is codeposited with a thermally decomposable organic powder, the codeposited layer being heated to decompose the organic filler and produce a porous coating of from about 20 to about 33% voids.

123 citations

Patent
28 Sep 1992
TL;DR: Abradable coatings formed by thermal spraying the powders abrade readily to form abradable seals as mentioned in this paper, and have a metal, metal alloy, or ceramic matrix with discrete inclusions of solid lubricant and plastic.
Abstract: Thermal spray powders are characterized by the presence of a matrix-forming component, a solid lubricant component and a plastic component. Abradable coatings formed by thermal spraying the powders abrade readily to form abradable seals. The abradable coatings have a metal, metal alloy, or ceramic matrix with discrete inclusions of solid lubricant and plastic. The thermal spray powders may be prepared as mechanically fused agglomerates.

92 citations

Patent
26 Dec 1973
TL;DR: Abradable seal composite as mentioned in this paper is an abradable composite with a porous, abrasionable ceramic surface layer which is resistant to high temperature oxidation and a metallic bottom layer capable of being bonded to a metallic substrate.
Abstract: Abradable seal composite structure having a porous, abradable ceramic surface layer which is resistant to high temperature oxidation and a metallic bottom layer capable of being bonded to a metallic substrate, with at least two intermediate layers consisting of ceramic/metal mixtures. The intermediate layer next to the ceramic layer has the highest ceramic content, with the remaining intermediate layers having progressively lower ceramic content and correspondingly higher metallic contents. The composite is made by laying up the layers in wet paste form and then drying them, after which the composite can be heated to bond it to the metallic substrate.

89 citations

Patent
14 May 1981
TL;DR: A thermal turbomachine casing having a multilayer heat insulation liner including a metallic bond coat in direct contact with the casing wall, a ceramic heat insulation layer bonded to the bond coat, and preferably an abradable coating in the form of a porous, predominantly metallic, top layer bond to the ceramic layer is described in this paper.
Abstract: A thermal turbomachine casing having a multilayer heat insulation liner including a metallic bond coat in direct contact with the casing wall, a ceramic heat insulation layer bonded to the bond coat, and preferably an abradable coating in the form of a porous, predominantly metallic, top layer bonded to the ceramic layer. A metallic honeycomb may be fixed to the casing wall, in which case the bond coat, ceramic layer, and top layer are within the cells of the honeycomb. The bond coat and ceramic layer may partially or completely fill the honeycomb cells. The layers may be deposited by flame or plasma spraying, preferably after peening the casing wall. Each succeeding layer is deposited before any cooling of the preceeding layer.

82 citations