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Publication numberUS3692554 A
Publication typeGrant
Publication dateSep 19, 1972
Filing dateDec 3, 1970
Priority dateDec 5, 1969
Also published asCA924970A1, DE1961047A1, DE1961047B2
Publication numberUS 3692554 A, US 3692554A, US-A-3692554, US3692554 A, US3692554A
InventorsKarl Bungardt, Gunter Lehnert, Helmut Meinhardt
Original AssigneeDeutsche Edelstahlwerke Ag
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Production of protective layers on cobalt-based alloys
US 3692554 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

SP 19, 1972 K. BUNGARDT ETAL PRODUCTION OF PROTECTIVE LAYERS ON COBALT-BASED ALLOYS Filed Dec. 5, 1970 United States IPatent Office 3,692 554 PRODUCTION F PROTECTIVE LAYERS ON COBALT-BASED ALLOYS Karl Buugardt, Gunter Lehnert, and Helmut Meinhardt,

Krefeld, Germany, assignors to Deutsche Edelstahll ABSTRACT OF THE- DISCLOSURE Cobalt-based alloys have their surface treated to provide high-temperature corrosion resistance, by diffusing nickel, a metal of the Platinum Group, and aluminum into the surface of the alloy. The metals may be heat-diffused simultaneously or in succession.

This invention relates to a method of producing on the surface of parts made of cobalt-based alloys protective, diffusion layers that are resistant at high temperatures to oxidation, scaling and corrosion.

It is a known practice to protect objects, for example turbine blades for jet propulsion engines which usually consist of high temperature metal alloys, from oxidation, scaling and corrosion, by diffusing aluminum into their surfaces thereby to provide a protective layer thereon.

The object of the present invention is to provide on parts made of high temperature metals, particularly cobalt-based alloys, a protective layer which imparts irnproved resistance to oxidation, scaling and corrosion at high temperatures.

For achieving this object the present invention consists in applying to the parts, possibly after they have been previously cleaned and degreased, nickel, one or more metals of the platinum group of metals of the `Periodic System of Elements (preferably platinum), and aluminum, either simultaneously or in succession, and to diffuse the said metals into the surface of the parts.

In a useful embodiment of the method of the invention, layers of nickel, of metal(s) of the platinum group and of aluminum may be consecutively applied to the surface of the part, for example by mechanical or electrolytic means, dipping, spraying or otherwise, and the metals in the layers thus formed diffused severally or jointly into the surface of the part by a diffusion heat treatment.

In an alternative method of carrying out the invention a layer of nickel and then a layer of one or more metals of the platinum group may be electrolytically deposited and the aluminum then deposited from a gas phase on the surface of the part and diffused into the surface of the part together with the nickel and the metal(s) of the platinum group. With advantage the part that has first been provided with a nickel layer and then with a layer of metal(s) of the platinum group, may be embedded in a powder mixture containing metallic aluminum possibly associated with a small proportion of a metal halide and an inert filler (e.g. alumina), the aluminum being then deposited on the part from a gas phase and finally diffused into the surface of the part together with the nickel and the metal(s) of the platinum group. Such a mixture may for example comprise about of aluminum and about 95% of the inert filler.

Cobalt-based alloys that have been provided with a protective diffusion layer according to the invention last about twice as long as similar parts that have been provided with a protective aluminum diffusion layer without nickel and platinum. The graph of the accompanying 4 Claims 3,692,554 Patentedv Sept. 19, 1972 drawing having time, expressed in hours', on the abscissa and change in weight, expressed in milligrams per square centimeter, on the ordinate shows, as a function of operating time, the change in weight-of test pieces that have been aluminized by a conventional method, and that have been protected by the method according to the invention. It will be seen that the reduction in weight which indicates the rate at which material is lost from the surface of the tested part by oxidation, scaling and corrosion, is less for p'arts protected according to the invention` than parts that have been merely aluminized, and that their useful life of 600 to 700 hours in scaling test when exposed to burnt natural gas at 1100 C. with an air factor of 1.2, is twice as long. The material of all the tested parts was a cobalt alloy containing I0.45% carbon, less than 0.5% silicon, less than 0.5% manganese, r21.0% chromium, less than 1.0% nickel, 11.0% tungsten, 2.0% nio# bium or tantalum, 1.75% iron, balance cobalt. The protective treatment of the parts accordingv to the invention was as follows: .4 v

PRELIMINARY SURFACE TREATMENT Electrolytic composition of bath:

240 g./litre of nickel chloride (NiClZ-HZO) 120 g./litre of 36% hydrochloric acid. Conditions of electrolysis: temperature 45 C. and current density 10-11 amps/sq. dm. Thickness of nickel deposit: 20 microns.

Heat treatment 2 hours at 260 C. followed by 3 hours at 450 C.

PRELIMINARY SURFACE TREATMENT OF THE NICKEL BEFORE PLATINISATION Degreasing in a cyanide degreasing bath as hereinbefore described cathodically 10 seconds, anodically 2O seconds and cathodically l0 seconds at a temperature of 20 C. and a current density of 5 amps/ sq. dm., followed by pickling in 10% by weight caustic soda cathodically 3 seconds and anodically 10 seconds at a temperature of 50 C. and a current density of 10 amps/sq. dm., followed by pickling in 4% hydrochloric acid cathodically 2 seconds and anodically 30 seconds at a temperature of 40 C. and a current density of 2.5 amps/sq. dm., followed by washing in warm water at C.

Platinum deposition Electrolytic composition of bath:

13 g./litre of hexachloroplatinic acid, HzPtCl 45 g./litre of triammonium phosphate, (NH4)3PO4 240 g/litre of disodium phosphate, Na2HPO4.

The result of this treatment was an overall thickness of the protective diffusion layer of 60 microns.

Similar results are obtainable with palladium, rhodium and/or ruthenium when used instead of platinum.

What is claimed is:

l. A method of producing protective di'usion layers that are resistant to oxidation, scaling and-corrosion at high temperatures on the surface of a cobalt-based alloy part, comprising the steps of depositing successively first nickel,r and then one or more metals of the group consisting of platinum, rhodium, ruthenium and palladium onto the surface of the said metal part, heating said coated part to, diiusion temperature while at the same time` aluminum from a gas phase is diffused into the surfaceA of the said coated metal part.

A method according to claim 1 in 4which the said metal part4 coated with nickel and then with a metal layer of one or more metals of the group consisting of platinum, rhodium, ruthenium and palladium is embedded in a powder mixture comprising metallic aluminum and anfinert filler, and subjected in said powder mixture to a, diffusion treatment whereby aluminum from the gas phase diffuses ,into the surface of the said metal part.

3. A method according to claim 2 wherein the said powder mixture comprises about 5% by weight of metallic aluminum and about 95% by weight of inert filler.

4. A method according Ainert filler is alumina.

References Cited UNITED STATES PATENTS 3,107,175Y 1,0/ 1963 Cape v .v `1,17--22 X 3,079,276 v2/1963 vVl'uyear et al 117-131 X 3,494,748 2/1970 Todd, 117f131 X 2,664,873 1/ 1954 Graham V v -a 1174-22 X 2,682,101 6 /19544 Whitfield et al. 117-71 MX 2,917,818 Y121'1959 Thomson j f 7204-7-38 SX FOREIGN PATENTS 1,553,233 1/1969 France 11T- 107.2 P

ALFRED L. LEAVIT T, Primary Examiner I. R. BATTEN,"IR., Assistant Examiner-vv U.S. Cl. X.R.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3819338 *Sep 17, 1971Jun 25, 1974Deutsche Edelstahlwerke AgProtective diffusion layer on nickel and/or cobalt-based alloys
US3961910 *Jan 8, 1975Jun 8, 1976Chromalloy American CorporationRhodium-containing superalloy coatings and methods of making same
US3979273 *May 27, 1975Sep 7, 1976United Technologies CorporationMethod of forming aluminide coatings on nickel-, cobalt-, and iron-base alloys
US3999956 *Feb 21, 1975Dec 28, 1976Chromalloy American CorporationResistance to high temperature oxidation and sulfidation
US4070507 *Jul 29, 1976Jan 24, 1978Chromalloy American CorporationPlatinum-rhodium-containing high temperature alloy coating method
US4439470 *May 7, 1982Mar 27, 1984George Kelly SieversMethod for forming ternary alloys using precious metals and interdispersed phase
US4656099 *Sep 6, 1983Apr 7, 1987Sievers George KCorrosion, erosion and wear resistant alloy structures and method therefor
US4962005 *Oct 11, 1989Oct 9, 1990Office National D'etudes Et De Recherches AerospatialesAluminization preceeded by a predeposition of palladium and at least one of nickel, cobalt and chromium as barrier metals
US5057196 *Dec 17, 1990Oct 15, 1991General Motors CorporationElectrophoretic deposition, heating, diffusion
US5334416 *Dec 23, 1992Aug 2, 1994Pohang Iron & Steel Co., Ltd.Heat resistant stainless steel coated by diffusion of aluminum and the coating method thereof
US5427866 *Mar 28, 1994Jun 27, 1995General Electric CompanyPlatinum, rhodium, or palladium protective coatings in thermal barrier coating systems
US5645893 *Dec 8, 1995Jul 8, 1997Rolls-Royce PlcThermal barrier coating for a superalloy article and method of application
US5650235 *Feb 28, 1994Jul 22, 1997Sermatech International, Inc.For a nickel-based superalloy substrates; gradient dispersion of nickel aluminide, platium aluminide and refractory metal silicide phases; heat and oxidation resistance; protective coatings for gas turbines
US5652044 *Mar 3, 1993Jul 29, 1997Rolls Royce PlcCeramic thermal barrier for gas turbine blades
US5658614 *Oct 28, 1994Aug 19, 1997Howmet Research CorporationPlatinum aluminide CVD coating method
US5667663 *Dec 19, 1995Sep 16, 1997Chromalloy United Kingdom LimitedMethod of applying a thermal barrier coating to a superalloy article and a thermal barrier coating
US5759380 *Apr 4, 1989Jun 2, 1998General Electric CompanyChromium, ruthenium aluminum alloy for coating on substrate
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US5897966 *Feb 26, 1996Apr 27, 1999General Electric CompanyHigh temperature alloy article with a discrete protective coating and method for making
US5981091 *Apr 22, 1997Nov 9, 1999Rolls-Royce PlcArticle including thermal barrier coated superalloy substrate
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US6207297Sep 29, 1999Mar 27, 2001Siemens Westinghouse Power CorporationBarrier layer for a MCrAlY basecoat superalloy combination
US7083827Feb 10, 1999Aug 1, 2006General Electric CompanyArticle such as turbine blade or vane; diffusing platinum into the substrate surface, and thereafter diffusing aluminum into the substrate surface
DE2601129A1 *Jan 14, 1976Sep 9, 1976Chromalloy American CorpVerfahren zur verbesserung der waerme- und korrosionswiderstandsfaehigkeit von formkoerpern aus waermeresistenten legierungen auf nickel-, kobalt- und nickel-kobalt-basis
EP1111091A1 *Dec 20, 2000Jun 27, 2001United Technologies CorporationMethod of forming an active-element containing aluminide as stand alone coating and as bond coat and coated article
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WO1983003988A1 *May 6, 1983Nov 24, 1983Turbine Metal Technology IncCorrosion, erosion and wear resistant alloy structures and method thereof
Classifications
U.S. Classification427/252, 205/176, 205/181, 428/680, 428/652, 205/228, 205/192, 428/941, 205/216, 428/669, 427/309
International ClassificationC22F1/10, C23C10/28, C23C10/52
Cooperative ClassificationC23C10/28, Y10S428/941
European ClassificationC23C10/28