Abstract: A component, especially a hot gas component of a turbomachine, has at least one passage (7, 7?), especially a cooling passage, which is embedded in an outer wall (5) of the component (1) of the turbomachine and basically extends parallel to the surface (6) of the component (1). The component (1) has a basic body (8) and at least one coating (9) which is applied to the basic body on the outside, and the passage (7, 7?) on one hand is formed by a cavity which is formed in the basic body (8), and on the other hand is closed off towards the surface (6) of the component (1) by the coating (9).

Abstract: A method of removing unwanted coating material from cooling passages of a turbine component includes determining coordinates of the position and orientation of cooling passages at the surface of the turbine component and determining reference points in the region of the cooling passages. After coating of the turbine component, the reference points are measured once again and the thickness of the coating is calculated. In a basic processing program, the data for the position, passage orientation and coating thicknesses and also CAD data for the cooling passages are interlinked and a laser processing program is automatically adapted for each individual cooling passage. Using the laser processing program, a pulsed laser is guided over disk-shaped volume segments of the unwanted coating material and the material is removed in the process.

Abstract: A leaf seal for sealing a shaft rotating about an axis, in particular in a gas turbine, includes a plurality of spaced-apart leaves arranged in a concentric circle around the axis and fixed in position by brazing, the leaves having surfaces oriented essentially parallel to the axis. The leaves are brazed to one another via intermediate spacers made of a brazing foil, so that a brazed joint is produced by brazing alloy from the brazing foils. The brazing temperature may be set to an optimum value just above the solidus temperature of the brazing foil, at which partial melting of the brazing foil occurs and penetration of liquid brazing alloy into the gap between the leaves is avoided.

Abstract: A method for removing casting defects (5) from an article (1) with an oriented microstructure can include locating at least one casting defect (5) and melting the casting defect (5) locally by a heat source (7) to a depth at least as great as the casting defect (5) itself. The molten material can then be solidified epitaxially with respect to the surrounding oriented microstructure of the article (1) in a way that the resulting solidified area is substantially free of any defect.

Abstract: A gas turbine component consists of a superalloy base material with a single crystal structure and a protective MCrAlY-coating (6). The MCrAlY-coating (6) has a g/g? single crystal structure, which is epitaxial with the base material. It has be determined the critical factors for the successful epitaxial and crack-free growth of the MCrAlY-coating (6).

Abstract: An automated machining process for machining of an obstructed passage (5) of an article (1) includes the steps of deriving the position and orientation of the passage (5) from automated processing of images of the passage (5) and additional information from a distance measurement device and saving positions and orientations of the passage (5) as local coordinates with respect to a reference coordinate system attached to the material that surrounds the passage (5). The saved positions and orientations of the passage (5) are used for subsequent removal of unwanted material from the obstructed passage (5).

Abstract: It is disclosed a method of applying a coating (12) with a controlled laser metal forming process. A light source with a specific power and a signal capturing apparatus is moved over an article (1) to form locally a melt pool (7) on the surface (5) of the article (1) to which a coating powder (8) is injected. An optical signal (13) is captured from the melt pool (7), and the monitored optical signal (13) is used for the determination of the temperature and temperature fluctuations of the melt pool (7). Furthermore, a control system (16) is used to adjust at least one process parameter such as the power of the light source to obtain desired melt pool properties. Subsequently the melt pool (7) solidifies. The high degree of control over the microstructure provides an efficient tool for generating laser metal formed hard coatings (12) with optimised wear properties.

Abstract: The invention discloses a thermal turbomachine having at least one row of rotor blades (1). At least one first rotor blade (1) has a greater radial length than the others and at the blade tip (2) is equipped with a first abrasive layer (72). At least one rotor blade (1) which has a shorter radial length than the first rotor blade (1) is equipped with a second abrasive layer (71) at the blade tip (2). The first abrasive layer (72) has a better cutting capacity and a lower thermal stability than the second abrasive layer (71). During commissioning of the thermal turbomachine, the first abrasive layer (72) is in contact with the abradable layer of the stator (8), and during continuous operation of the thermal turbomachine the second abrasive layer (71) is in contact with the abradable layer of the stator (8).

Abstract: A gas turbine component consists of a superalloy base material with a single crystal structure and a protective MCrAlY-coating. The MCrAlY-coating the MCrAlY has a ?/?-phase and single crystal structure, which is epitaxial with the base material.

Abstract: It is disclosed a method for fabricating, modifying or repairing of single crystal or directionally solidified articles. Two single crystal or directionally solidified prefabricated parts are joint by isothermally brazing using a brazing material. After that an epitaxial or non-epitaxial layer on the surface of the created article and of the braze joint is applied using a laser metal forming process.

Abstract: A method for removing casting defects (5) from an article (1) with an oriented microstructure can include locating at least one casting defect (5) and melting the casting defect (5) locally by a heat source (7) to a depth at least as great as the casting defect (5) itself. The molten material can then be solidified epitaxially with respect to the surrounding oriented microstructure of the article (1) in a way that the resulting solidified area is substantially free of any defect.

Abstract: A method for controlled remelting of or laser metal forming on the surface (5) of an article (1) can include moving a light source and a signal capturing apparatus over the article (1). The light source having a specific power can be used to melt the surface (5) of the article (1) locally and to form a melt pool (7). Thereby an optical signal (13) is captured by the signal capturing apparatus from the melt pool (7), and the monitored optical signal (13) is used for the determination of temperature and temperature fluctuations as properties of the melt pool (7). Furthermore, a control system (16) with a feedback circuit is used to adjust at least one process parameter such as the power of the light source such that desired melt pool properties are obtained. Subsequently the melt pool (7) solidifies.

Abstract: A gas turbine component consists of a superalloy base material with a single crystal structure and a protective MCrAlY-coating. The MCrAlY-coating the MCrAlY has a &ggr;/&bgr;-phase and single crystal structure, which is epitaxial with the base material.

Abstract: A gas turbine component consists of a superalloy base material with a single crystal structure and a protective MCrAlY-coating (6). The MCrAlY-coating (6) has a g/g′ single crystal structure, which is epitaxial with the base material. It has be determined the critical factors for the successful epitaxial and crack-free growth of the MCrAlY-coating (6).

Abstract: It is disclosed a method for fabricating, modifying or repairing of single crystal (SX) or directionally solidified (DS) articles (1). Two single crystal (SX) or directionally solidified (DS) prefabricated parts are joint by isothermally brazing using a brazing material. After that an epitaxial or non-epitaxial layer on the surface of the created article (1) and of the braze joint is applied using a laser metal forming process.

Abstract: It is disclosed a method of depositing a MCrAlY-coating (6) on the surface (5) of a single crystal (SX) or directionally solidified (DS) article (1). In a first step the article (1) is coated only at a local area by an electroplated method. In a second step the deposited MCrAlY-coating in single crystal form epitaxial with the base material of the article.

Abstract: In a temperature measurement method for determining the adiabatic temperature of a flame, in particular in the combustion chamber of a gas turbine, the chemiluminescence radiation from the flame, emitted by OH radicals and CH radicals, is detected using a spectrograph via an optical sensor fiber. The spectrally resolved raw signal of the chemiluminescence radiation is then corrected and compared with a multiplicity of theoretically determined emission spectra, until a theoretical emission spectrum coincides with the chemiluminescence spectrum. The Boltzmann temperature associated with this coinciding emission spectrum is then assigned to the chemiluminescence spectrum, the adiabatic flame temperature being derived from the Boltzmann temperature by correlation.