Coating processes – Spray coating utilizing flame or plasma heat – Metal or metal alloy coating
Reexamination Certificate
2000-12-14
2002-03-26
Jones, Deborah (Department: 1775)
Coating processes
Spray coating utilizing flame or plasma heat
Metal or metal alloy coating
C427S250000, C416S24100B, C416S24100B
Reexamination Certificate
active
06361835
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention proceeds from an iron aluminide coating and provides a method of applying an iron aluminide coating to a substrate.
2. Background
EP 0 625 585 B1 has disclosed a Fe—Cr—Al alloy possessing high oxidation resistance. Said alloy has been used to produce foils for catalyst supports in catalytic converters.
Coatings produced from this alloy, however, especially at high temperatures and as a coating of thermally stressed elements of thermal turbomachines, exhibited inadequate oxidation properties.
In order to apply heat insulation coats to blades, heat shields, etc. of thermal turbomachines and combustion chambers, it is common to apply to these elements a bonding layer by the vacuum plasma technique. Disadvantages of these bonding layers are that the bonding layer commonly fails at service temperatures above 900° C., and the heat insulation coat falls off, and also the inadequate oxidation resistance of the bonding layer.
SUMMARY OF THE INVENTION
Accordingly, one object of the invention is to improve the oxidation behavior of an iron aluminide coating of the type referred to at the outset.
This object is achieved in accordance with the invention by providing an iron aluminide coating having the following composition:
5-35 % by weight
aluminum
15-25% by weight
chromium
0.5-10% by weight
molybdenum, tungsten,
tantalum and/or niobium
0-0.3% by weight
zirconium
0-1 % by weight
boron
0-1 % by weight
yttrium
the remainder being iron and also impurities and additaments arising from its production.
One of the advantages of the invention is that the coating has good oxidation resistance, especially at temperatures above 1000° C. The use of intermetallic phases, moreover, has the advantage that the coating does not fail even at high temperatures; this is a particular advantage if the coating is used as a bonding layer for a heat insulation coat. The iron aluminide coating is therefore of outstanding suitability as a coating and bonding layer for thermally stressed elements of thermal turbomachines.
The ductile brittle transition temperature (DBTT) of the coatings of the invention is situated lower than that of conventional nickel-based coatings, which is highly advantageous for their use as coatings.
REFERENCES:
patent: 4004047 (1977-01-01), Grisik
patent: 4144380 (1979-03-01), Beltran et al.
patent: 4321311 (1982-03-01), Strangman
patent: 4429019 (1984-01-01), Schrewelius
patent: 4447503 (1984-05-01), Dardi et al.
patent: 4535034 (1985-08-01), Zaizen et al.
patent: 4880614 (1989-11-01), Strangman
patent: 4969960 (1990-11-01), Lehnert et al.
patent: 5411702 (1995-05-01), Nazmy et al.
patent: 5422070 (1995-06-01), Nazmy et al.
patent: 5512382 (1996-04-01), Strangman
patent: 5562998 (1996-10-01), Strangman
patent: 5667663 (1997-09-01), Rickerby et al.
patent: 0 061 322 (1982-09-01), None
patent: 85 03465 (1985-08-01), None
Nazmy Mohamed
Staubli Markus
Asea Brown Boveri AG
Burns Doane Swecker & Mathis L.L.P.
Jones Deborah
Savage Nazmy
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