Abstract: The present invention is directed to in situ methods for maintaining turbine assemblies. One such method includes: disposing a maintenance apparatus on the rotor; positioning the maintenance apparatus proximate to the damaged region by rotating the rotor; and repairing the damaged region by operating a repair tool disposed on the apparatus. Another method includes: disposing a maintenance apparatus on the stator; positioning the damaged region proximate to the maintenance apparatus by rotating the rotor; and repairing the damaged region by operating a repair tool disposed on the apparatus.

Abstract: A reconfigurable maintenance apparatus includes a body configured to operate within a cavity. The body has a first shape in a first configuration and a second shape in a second configuration. The first configuration facilitates the body entering the cavity. The reconfigurable apparatus also includes at least one maintenance device operably coupled to the body. The second configuration facilitates the at least one maintenance device of the reconfigurable apparatus performing a maintenance operation.

Abstract: Methods of forming an environmental barrier coating are disclosed. A method includes disposing a powder-based coating on a substrate, heat-treating the powder-based coating at a temperature greater than 800° C. and less than 1200° C. to form a porous coating that includes surface-connected pores, infiltrating at least some of the surface-connected pores of the porous coating with an infiltrant material to form an infiltrated coating, and sintering the infiltrated coating at a temperature greater than 1200° C. and less than 1500° C. to form the environmental barrier coating on the substrate.

Abstract: A reconfigurable maintenance apparatus includes a body configured to operate within a cavity. The body has a first shape in a first configuration and a second shape in a second configuration. The first configuration facilitates the body entering the cavity. The reconfigurable apparatus also includes at least one maintenance device operably coupled to the body. The second configuration facilitates the at least one maintenance device of the reconfigurable apparatus performing a maintenance operation.

Abstract: A maintenance apparatus includes a flexible carriage configured to anchor between adjacent airfoils of a turbine assembly. The maintenance apparatus includes a maintenance tool operably coupled with the flexible carriage. The maintenance tool is configured to one or more of generate image data representative of one or more surfaces of the turbine assembly or repair the one or more surfaces of the turbine assembly. The maintenance apparatus comprises one or more motors operably coupled with the maintenance tool and configured to move the maintenance tool relative to the flexible carriage.

Abstract: A motorized apparatus for use in maintaining a turbine assembly includes a body configured to move through the turbine assembly. The motorized apparatus also includes at least one maintenance device coupled to the body. The motorized apparatus further includes a drive system configured to move the body relative to the turbine assembly. The drive system includes a motor and a steering component. The steering component is configured to steer the motorized apparatus relative to the turbine assembly.

Abstract: A system for use in maintaining a turbine assembly includes a plurality of blades and a plurality of vanes. The system includes an insertion apparatus including an insertion end, a steering end opposite the insertion end, and a body extending from the insertion end to the steering end. The insertion end is positionable proximate at least one blade of the plurality of blades using a steering interface. The system also includes a service apparatus for use in maintaining the turbine assembly. The service apparatus includes at least one maintenance device and an anchoring feature. The service apparatus is proximate the insertion end of the insertion apparatus and is positionable in a plurality of orientations via the steering interface. The anchoring feature is configured to releasably couple the service apparatus to at least one blade of the plurality of blades.

Abstract: A service apparatus for use in maintaining a turbine assembly (100) includes a carriage (132, 304) configured to move through a cavity of the turbine assembly (100), a motorized system (218, 500, 600, 700, 800) coupled to the carriage (132, 304), and a maintenance device (128, 400) coupled to the motorized system (218, 500, 600, 700, 800). The motorized system (218, 500, 600, 700, 800) is configured to move the maintenance device (128, 400) relative to the carriage (132, 304). The motorized system (218, 500, 600, 700, 800) includes a first motor (710, 720, 805) configured to move the maintenance device (128, 400) in a first direction (324) and a second motor (710, 720, 805) configured to move the maintenance device (128, 400) in a second direction (324).

Abstract: A service apparatus for use in maintaining a machine including a stator and a rotor is provided. The service apparatus includes a carriage assembly configured to couple to the rotor. The service apparatus is selectively transitionable between a stowed position in which the service apparatus is rotatable with the rotor and an extended position in which the service apparatus is extended toward the stator. The service apparatus also includes at least one maintenance device coupled to the carriage assembly. The at least one maintenance device is operable to perform a maintenance operation on a surface of the stator with the service apparatus in the extended position.

Abstract: Methods for forming a sintered bond coat (64) on a silicon-based substrate (14) and articles (50) formed by the methods are disclosed. The methods include applying a bond coat slurry on the silicon-based substrate (14), drying the bond coat slurry on the silicon-based substrate to form a dried bond coat (44), and sintering the dried bond coat (44) in an oxidizing atmosphere to form a sintered bond coat (64) on the silicon-based substrate (14). The bond coat slurry includes a bond coat patching material in a bond coat fluid carrier. The articles (50) include a silicon-based substrate (14), a sintered bond coat (64) formed on the silicon-based substrate (14), and a sintered environmental barrier coating (EBC) (66) formed on the sintered bond coat (64). The sintered bond coat (64) includes a silicon-based phase and an oxide of the silicon-based phase.

Abstract: A system for use in maintaining a machine including a cavity is provided. The system includes a pilot apparatus including an insertion end and a steering end opposite the insertion end. The insertion end is positionable within the machine such that the pilot apparatus defines a path through the machine. The system also includes a steering interface configured to steer the insertion end relative to the machine. The system further includes a service apparatus for use in maintaining the machine. The service apparatus is configured to move along the path defined by the pilot apparatus.

Abstract: A method for forming a patch repair on a silicon-based component is disclosed. The method includes applying a patch on a damaged area of a silicon-based component, drying the patch to form a dried patch, and sintering in situ the dried patch to form a patch repaired portion of the silicon-based component. The patch includes a patching material and the patching material includes a plurality of nanoparticles having a median particle size less than 100 nanometers. The plurality of nanoparticles includes at least one of silicon, silicon alloy, silica, or a metal silicate.

Abstract: A system for use in maintaining a machine including a cavity is provided. The system includes a pilot apparatus including an insertion end and a steering end opposite the insertion end. The insertion end is positionable within the machine such that the pilot apparatus defines a path through the machine. The system also includes a steering interface configured to steer the insertion end relative to the machine. The system further includes a service apparatus for use in maintaining the machine. The service apparatus is configured to move along the path defined by the pilot apparatus.

Abstract: An article includes a substrate and a coating provided on a surface of the substrate. The coating includes at least one metal silicide layer consisting essentially of MoSi2 or WSi2 or (Mo, W)Si2 or a platinum group metal silicide and at least one layer consisting essentially of Si3N4.

Abstract: A manufacturing method includes forming one or more grooves in a component that comprises a substrate with an outer surface. The substrate has at least one interior space. Each groove extends at least partially along the substrate and has a base and a top. The manufacturing method further includes applying a structural coating on at least a portion of the substrate and processing at least a portion of the surface of the structural coating so as to plastically deform the structural coating at least in the vicinity of the top of a respective groove, such that a gap across the top of the groove is reduced. A component is also disclosed and includes a structural coating disposed on at least a portion of a substrate, where the surface of the structural coating is faceted in the vicinity of the respective groove.

Abstract: A reconfigurable maintenance apparatus includes a body configured to operate within a cavity. The body has a first shape in a first configuration and a second shape in a second configuration. The first configuration facilitates the body entering the cavity. The reconfigurable apparatus also includes at least one maintenance device operably coupled to the body. The second configuration facilitates the at least one maintenance device of the reconfigurable apparatus performing a maintenance operation.

Abstract: A turbine component patch delivery system can include a compressed gas source fluidly connected to a delivery line comprising a dispensing end. The turbine component patch delivery system can further include one or more turbine component patch carriers that can be projected out of the dispensing end of the delivery line by the compressed gas source, wherein each of the one or more turbine component patch carriers comprise a turbine component patch material housed within a breakaway shell.

Abstract: A motorized apparatus for use in maintaining a turbine assembly includes a body configured to move through the turbine assembly. The motorized apparatus also includes at least one maintenance device coupled to the body. The motorized apparatus further includes a drive system configured to move the body relative to the turbine assembly. The drive system includes a motor and a steering component. The steering component is configured to steer the motorized apparatus relative to the turbine assembly.

Abstract: The disclosure provides for an article including a substrate, an environmental barrier coating (EBC), a bondcoat and a boron source. The substrate may include a silicon-including ceramic material. The EBC may be disposed over the substrate, and the bondcoat may disposed between the substrate and the EBC. The bondcoat may include silicon. The boron source may be disposed within the article to provide an effective amount of boron to form an oxide including silicon and at least 0.1 weight percent boron during exposure of the bondcoat to an oxidizing environment at a temperature greater than 900 degrees Celsius. The oxide may be a borosilicate glass that is substantially devitrification resistant to prevent spallation of the EBC and thereby enhance the temperature capability of the article.

Abstract: A maintenance apparatus includes a flexible carriage configured to anchor between adjacent airfoils of a turbine assembly. The maintenance apparatus includes a maintenance tool operably coupled with the flexible carriage. The maintenance tool is configured to one or more of generate image data representative of one or more surfaces of the turbine assembly or repair the one or more surfaces of the turbine assembly. The maintenance apparatus comprises one or more motors operably coupled with the maintenance tool and configured to move the maintenance tool relative to the flexible carriage.