摘要:
A method to form an improved hybrid ceramic matrix composite structure comprises providing a ceramic matrix composite (CMC) with open features at a surface and applying a thermal barrier coating to the surface. The thermal barrier coating is preferably a friable graded insulation coating (FGI) having hollow ceramic spheres. For acceptance of a FGI coating the open features have a center-to-center separation distance in one or more directions that is between about 100 and about 1,000 percent of the diameter of the hollow ceramic spheres in the FGI and a depth that is between about 20 percent and about 200 percent of the diameter of the hollow ceramic spheres in the FGI. The open feature can result from the winding of tows about a mandrel; the lay-up of fabric including a surface fabric having an open weave; or the use of a 3-D weave, or a 3-D braid.
摘要:
A method of manufacturing a hybrid structure (100) having a layer of CMC material (28) defining an interior passageway (24) and a layer of ceramic insulating material (18) lining the passageway. The method includes the step of casting the insulating material to a first thickness required for effective casting but in excess of a desired second thickness for use of the hybrid structure. An inner mold (14) defining a net shape desired for the passageway remains in place after the casting step to mechanically support the insulating material during a machining process used to reduce the thickness of the insulating material from the as-cast first thickness to the desired second thickness. The inner mold also provides support as the CMC material is deposited onto the insulating material. The inner mold may include a fugitive material portion (20) to facilitate its removal after the CMC material is formed.
摘要:
A composite material (10) formed of a ceramic matrix composite (CMC) material (12) protected by a ceramic insulating material (14). The constituent parts of the insulating material are selected to avoid degradation of the CMC material when the two layers are co-processed. The CMC material is processed to a predetermined state of shrinkage before wet insulating material is applied against the CMC material. The two materials are then co-fired together, with the relative amount of shrinkage between the two materials during the firing step being affected by the amount of pre-shrinkage of the CMC material during the bisque firing step. The shrinkage of the two materials during the co-firing step may be matched to minimize shrinkage stresses, or a predetermined amount of prestress between the materials may be achieved. An aluminum hydroxyl chloride binder material (24) may be used in the insulating material in order to avoid degradation of the fabric (28) of the CMC material during the co-firing step.
摘要:
A gas turbine component (20) with a layer of ceramic material (22) defining a wear surface (21), in which an array of cross-shaped depressions (26A, 26B) formed in the wear surface (21) define a continuous labyrinth of orthogonal walls (28, 30) of the ceramic material, and reduce the area of the wear surface (21) by about 50%. Within a representative area (36) of the wear surface (21), the depressions (26A, 26B) provide a ratio of a lineal sum of depression perimeters (27) divided by the representative area (36) of the wear surface of least 0.9 per unit of measurement for improved abradability characteristics of the wear surface (21).
摘要:
A method for joining a first CMC part (30) having an outer joining portion (32), and a second CMC part (36) having an inner joining portion (38). The second CMC part (36) is heat-cured to a stage of shrinkage more complete than that of the first CMC part (30) prior to joining. The two CMC parts (30, 36) are joined in a mating interface that captures the inner joining portion (38) within the outer joining portion (32). The assembled parts (30, 36) are then fired together, resulting in differential shrinkage that compresses the outer joining portion (32) onto the inner joining portion (38), providing a tightly pre-stressed joint. Optionally, a refractory adhesive (42) may be used in the joint. Shrinkage of the outer joining portion (32) avoids shrinkage cracks in the adhesive (42).
摘要:
A method of making a combustion turbine component includes forming a metallic body by direct metal fabrication (DMF) to have at least one surface portion defining a first plurality of surface cooling features each having a first dimension and at least one second surface cooling feature on at least one of the first plurality of surface cooling features and having a second dimension less than said first dimension and less than 200 μm. Forming the metallic body by DMF may include forming a plurality of metallic combustion turbine subcomponent greenbodies by DMF and assembling the plurality of metallic combustion turbine subcomponent greenbodies together to form a metallic greenbody assembly. The metallic greenbody assembly may be sintered to thereby form the metallic body.
摘要:
A method of making a combustion turbine component includes forming a metallic body by direct metal fabrication (DMF) to have at least one surface portion defining a first plurality of surface cooling features each having a first dimension and at least one second surface cooling feature on at least one of the first plurality of surface cooling features and having a second dimension less than said first dimension and less than 200 μm. Forming the metallic body by DMF may include forming a plurality of metallic combustion turbine subcomponent greenbodies by DMF and assembling the plurality of metallic combustion turbine subcomponent greenbodies together to form a metallic greenbody assembly. The metallic greenbody assembly may be sintered to thereby form the metallic body.
摘要:
A gas turbine component (20) with a layer of ceramic material (22) defining a wear surface (21), in which an array of cross-shaped depressions (26A, 26B) formed in the wear surface (21) define a continuous labyrinth of orthogonal walls (28, 30) of the ceramic material, and reduce the area of the wear surface (21) by about 50%. Within a representative area (36) of the wear surface (21), the depressions (26A, 26B) provide a ratio of a lineal sum of depression perimeters (27) divided by the representative area (36) of the wear surface of least 0.9 per unit of measurement for improved abradability characteristics of the wear surface (21).
摘要:
A enhanced abradable friable graded insulator FGI results from the laser patterning of a coating where a series of top surfaces reside on a series of columns such that the walls of the columns are not significantly densified relative to the interior of the columns. Patterns can be generated where the columns are oriented independently normal to or at an acute angle to the top surfaces. The cross sections of the top surfaces are formed to conform to the average dimensions of the spheres of the FGI coating. The cross sections of the top surfaces can be more than 1.5 times the diameter of the spheres. Various patterns of top surfaces can be used including regular, random, quasiperiodic patterns. A gradient of abradability can be imposed on the coating.
摘要:
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).