What is claimed is:
1. A thermal barrier coating system for a superalloy article, the coating system comprising:
a superalloy substrate, the superalloy material being capable of forming an adherent alumina layer;
a bond coat applied to a localized area of the substrate such that a portion of the substrate remains exposed;
a thin adherent alumina layer formed on the exposed portion of the substrate and on the bond coat; and
a ceramic layer applied on the alumina layer.
2. The system according to claim 1, wherein the bond coat is an MCrAIY or aluminide bond coat.
3. The system according to claim 1, wherein the localized area is an area susceptible to premature failure of the ceramic layer.
4. The system according to claim 1, wherein the substrate comprises an airfoil having a leading edge and a trailing edge.
5. The system according to claim 4, wherein the bond coat is applied to at least one of the leading edge and the trailing edge of the airfoil.
6. The system according to claim 1, wherein the bond coat is plasma sprayed.
7. The system according to claim 1, wherein the bond coat has a thickness of less than about 5 mils.
8. The system according to claim 1, wherein the ceramic layer has a columnar microstructure.
9. The system according to claim 1, wherein the localized areas of the article are prone to damage by particulate matter or debris.
10. The system according to claim 1, wherein the bond coat is applied to less than about 50% of the substrate airfoil area.
11. A superalloy article comprising:
a superalloy substrate;
a bond coat applied to at least one local area of the substrate such that a remaining portion of the substrate is exposed.
12. The article according to claim 11, wherein the superalloy material is capable of forming an adherent alumina layer, and further comprising:
a thin adherent alumina layer formed on the exposed portion of the substrate and the bond coat.
13. The article according to claim 11, further comprising:
a ceramic layer applied on the alumina layer.
14. The article according to claim 11, wherein the bond coat is an MCrAlY or aluminide bond coat.
15. The article according to claim 11, wherein the local area is susceptible to premature failure of the ceramic layer.
16. The article according to claim 11, wherein the substrate comprises an airfoil having a leading edge and a trailing edge.
17. The article according to claim 16, wherein the bond coat is applied to at least one of the leading edge and the trailing edge of the airfoil.
18. The article according to claim 11, wherein the bond coat has a thickness of less than about 5 mils.
19. The article according to claim 13, wherein the ceramic layer has a columnar microstructure.
20. The article according to claim 11, wherein the bond coat is applied to less than 50% of the area defined by the substrate.
21. A method of reducing the weight of a ceramic coated article having a superalloy substrate, an adherent bond coat on the substrate, a thin alumina layer formed on the bond coat and an adherent ceramic on the alumina layer, comprising the steps of:
providing a superalloy substrate, the superalloy material being capable of forming an adherent alumina layer;
applying a bond coat to at least one local area of the substrate such that a remaining portion of the substrate remains uncovered;
forming a thin adherent alumina layer on the remaining portion of the substrate and on the bond coat; and
applying a ceramic layer on the alumina layer.
22. The method according to claim 21, wherein the bond coat that is applied is an MCrAlY or aluminide bond coat.
23. The method according to claim 21, wherein the at least one local area to which the bond coat is applied comprises an area susceptible to premature failure of the ceramic layer.
24. The method according to claim 21, wherein the substrate provided comprises an airfoil having a leading edge and a trailing edge.
25. The method according to claim 21, wherein the bond coat is applied to at least one of the leading edge and the trailing edge of the airfoil.
26. The method according to claim 21, wherein the step of applying the bond coat is performed by plasma spraying.
27. The method according to claim 21, wherein the ceramic layer is applied to provide the ceramic with a columnar microstructure.
28. The method according to claim 21, wherein the bond coat is applied to less than about 50% of the substrate area.
29. A thermal barrier coating system for a superalloy article, the coating system comprising:
a superalloy substrate;
an aluminide coating applied to the substrate;
an MCrAlY bond coat applied to a localized area of the aluminide such that a portion of the aluminide remains exposed, the aluminide coating and the MCrAlY bond coat forming a thin adherent alumina layer; and
a ceramic layer on the alumina layer.
30. The system according to claim 29, wherein the localized area is an area susceptible to premature failure of the ceramic layer.
31. The system according to claim 29, wherein the substrate comprises an airfoil having a leading edge and a trailing edge, and the bond coat is applied to at least one of the leading edge and the trailing edge.
32. The system according to claim 29, wherein the ceramic layer has a columnar microstructure.
33. The system according to claim 29, wherein the localized areas of the article are prone to damage by particulate matter or debris.
34. The system according to claim 29, wherein the bond coat is applied to less than about 50% of the aluminide area.
35. A thermal barrier coating system for a superalloy article, the coating system comprising:
a superalloy substrate;
an MCrAlY bond coat applied to a localized area of the substrate such that a portion of the substrate remains exposed;
an aluminide coating applied to the exposed portion of the substrate and to the bond coat, the aluminide coating and the MCrAlY bond coat forming a thin adherent alumina layer; and
a ceramic layer on the alumina layer.
36. The system according to claim 35, wherein the localized area is an area susceptible to premature failure of the ceramic layer.
37. The system according to claim 35, wherein the substrate comprises an airfoil having a leading edge and a trailing edge, and the bond coat is applied to at least one of the leading edge and the trailing edge.
38. The system according to claim 35, wherein the ceramic layer has a columnar microstructure.
39. The system according to claim 35, wherein the localized areas of the article are prone to damage by particulate matter or debris.
40. The system according to claim 35, wherein the bond coat is applied to less than about 50% of the substrate area.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A module for at least one combustion cylinder of an internal combustion engine having electrohydraulic valve control, comprising:
a cylinder head having a plurality of gas exchange valves, at least one gas exchange valve functioning as an inlet valve to control the at least one inlet opening, and at least one other gas exchange valve functioning as an outlet valve to control the at least one outlet opening, at least one high pressure line for supplying fluid under high pressure, at least one recycling line for recycling of fluid, wherein the at least one high pressure line and the at least one recycling line each have at least one coupling opening for hydraulic coupling of the electrohydraulic valve actuators;
a plurality of electrohydraulic valve actuators; and
an arrangement for detachably fastening the electrohydraulic valve actuators;
wherein the number of the electrohydraulic valve actuators corresponds to the number of the gas exchange valves present, and
wherein each valve actuator has an actuator housing, the housing having a planar surface with a fluid supply opening, a fluid outflow opening and a leadthrough passage enclosed by a projecting hollow peg for allowing passage of a valve shaft of a gas exchange valve, wherein the fluid supply opening, the fluid outflow opening and the leadthrough passage are arranged in such a way that, at each valve actuator the fluid supply opening rests congruently on the coupling opening of the high pressure line and the fluid outflow opening rests congruently on the coupling opening of the recycling line, and the hollow peg engages the centering opening in a form-locking manner.
2. The module as recited in claim 1, wherein in the actuator housing, two blind hole-like accommodating chambers are provided per each electrical control valve, the accommodating chambers each opening out onto a housing surface that faces away from the planar housing surface, and wherein a connecting channel extends from the bottom of each accommodating chamber to the inside of the hollow peg.
3. The module as recited in claim 1, wherein in the planar housing surface, ring grooves surrounding the fluid supply opening and the fluid outflow opening are provided for accommodating sealing rings.
4. The module as recited in claim 1, wherein a cavity coaxial with the hollow peg is provided in the actuator housing, and wherein a hydraulic working cylinder connected to the fluid supply opening and the fluid outflow opening is installed into the cavity, and wherein an operating piston guided in a working cylinder in an axially shiftable manner is connected to the valve shaft of the gas exchange valve that is inserted into the hollow peg.
5. The module as recited in claim 1, wherein through holes are provided in the actuator housing for allowing passage of fastening screws adapted to be screwed into threaded holes in the cylinder head.