Coated cast part

Details Coated cast part Coated cast part

1999-02-02

2001-06-26

Jones, Deborah (Department: 1775)

Stock material or miscellaneous articles

All metal or with adjacent metals

Having metal particles

C428S593000, C428S609000, C428S613000, C428S621000, C428S632000, C428S633000, C415S173400, C415S173500, C415S174400, C415S174500

Reexamination Certificate

active

06251526

ABSTRACT:

The invention relates to a coated cast part in which a skeleton structure is cast on the surface of a basic body and onto which a coating is applied. This invention relates to to uses of a cast part of this kind and to a turbine blade which represents an example of the cast part in accordance with the invention.
BACKGROUND OF THE INVENTION
It is essential for a good efficiency of a gas turbine or an aeroplane engine that sealing gaps between the turbine blades and the housing are made very small. Under adverse operating conditions a scraping between the blade tips and the inner surface of the housing can result. For this reason “abradables” have been developed as a coating of the housing surface. In the event of a scraping, the blade tips release fine particles from the abradable layers without their being damaged thereby. The abradable layers are manufactured in particular by thermal spraying on of ceramic powders (e.g. “HVFS” or “APS”, i.e. high velocity flame spraying or atmospheric plasma spraying). It is known that the thermal expansion of a ceramic coating is substantially less than that of a coated metallic basic body. Therefore, due to the high operating temperatures, suitable intermediate layers (“bond coats”) must be provided which counteract a breaking off of the coating.
Similar problems are present in combustion chambers of gas turbines, in inlet segments or in guide blades. Heat insulating coatings of a ceramic material must be suitably anchored on a surface to be screened off.
Thick ceramic coatings adhere to a basic body as a rule only when a bond coat has been previously applied to it. Such bond coats often contain oxidisable components. A ceramic coating of zirconium oxide is permeable to oxygen ions at high temperatures. Therefore an oxidation of the bond coat can result which—if it is combined with a volume increase—can lead to a breaking off of the coating.
SUMMARY OF THE INVENTION
The object of the invention is to provide a coated cast part which comprises means with which a coating adheres well to a basic body to be coated in spite of greatly differing coefficients of expansion. This object is satisfied by the cast part covered by a skeleton structure which is adhered to the surface of the cast part and onto which a coating is applied. Thanks to a special structuring of the surface, the basic body of this cast part forms a substrate for a thick ceramic layer which is tolerant of expansion and at the same time has good anchoring properties for this layer.
The cast part has a basic body of a first material and a coating of at least one second material. The second material is applied on a co-cast skeleton structure at the surface of the basic body, with it forming a covering or cover layer.
The special coatings and geometrical properties of the skeleton structure which are particularly advantageous with respect to the cases usually occurring in which the surfaces to be coated are curved. A relief-like surface structuring which is, for example, suitable for a shaft seal of a flow machine in the form of a labyrinth seal. Use of the coating in accordance with the invention as a functional element in various apparatuses is disclosed. A turbine blade is a further example of a cast part in accordance with the invention.


REFERENCES:
patent: 4209334 (1980-06-01), Panzera
patent: 4273824 (1981-06-01), McComas et al.
patent: 4639388 (1987-01-01), Ainsworth et al.
patent: 4867639 (1989-09-01), Strangman
patent: 5057379 (1991-10-01), Fayeulle et al.
patent: 5064727 (1991-11-01), Naik
patent: 533531 (1981-12-01), None
patent: 8411277 U (1986-09-01), None
patent: 0067746A1 (1982-12-01), None
patent: 2513723 (1983-04-01), None
patent: 1169347 (1969-11-01), None
patent: 2010711A (1979-07-01), None
patent: 2062115A (1981-05-01), None
patent: WO 97/22566 (1997-06-01), None

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