EP0731187A1 - Verfahren zur Erzeugung einer Schutzdiffusionsschicht auf Legierungen auf Nickel-, Kobalt- und Eisenbasis - Google Patents

Verfahren zur Erzeugung einer Schutzdiffusionsschicht auf Legierungen auf Nickel-, Kobalt- und Eisenbasis Download PDF

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Publication number
EP0731187A1
EP0731187A1 EP96301522A EP96301522A EP0731187A1 EP 0731187 A1 EP0731187 A1 EP 0731187A1 EP 96301522 A EP96301522 A EP 96301522A EP 96301522 A EP96301522 A EP 96301522A EP 0731187 A1 EP0731187 A1 EP 0731187A1
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EP
European Patent Office
Prior art keywords
coating
source
aluminum
ptal
heating
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
EP96301522A
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English (en)
French (fr)
Inventor
Srivivasan Shankar
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Turbine Components Corp
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Turbine Components Corp
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Filing date
Publication date
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Publication of EP0731187A1 publication Critical patent/EP0731187A1/de
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C23C10/06—Solid state diffusion of only metal elements or silicon into metallic material surfaces using gases
    • C23C10/08—Solid state diffusion of only metal elements or silicon into metallic material surfaces using gases only one element being diffused
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C23C10/02—Pretreatment of the material to be coated

Definitions

  • the present invention relates to a method for forming protective diffusion layers on nickel, cobalt, and iron base alloy parts and, more particularly, to a method for selectively applying a platinum aluminide coating on external surfaces of such parts and a simple aluminide coating on internal surfaces of such parts.
  • the method of the present invention has particular utility in the formation of protective diffusion layers on gas turbine engine components.
  • One method which has been used to form these types of coatings is a pack cementation technique in which the article to be protected is placed in contact with or embedded within a powder mixture of aluminum or an aluminum alloy, a chemical transfer agent, usually a fluoride or chloride salt, and an inert diluent such as alumina.
  • the powder mixture used in this technique forms a source of aluminizing gas species.
  • the powder mixture is heated while the part being coated is within or in contact with the mixture.
  • pack cementation techniques 150 - 154 discusses such known pack cementation techniques.
  • Other articles discussing pack cementation techniques include "Kinetics of Pack Aluminization of Nickel", by L. L. Seigle et al., NASA Contractor Report 2939, and "Interdiffusion and Intrinsic Diffusion In the NiAl Phase of the Al-Ni System" by S. Shankar et al., Metalluraical Transactions A, Vol. 9A, Oct. 1978, p. 1467.
  • gaseous aluminizing species must travel through the powder packs and through the region where the substrate being coated contacts the pack. As a consequence, less than desirable coatings can be formed. For this and other reasons, it is desirable to coat the article using a technique wherein the part being coated is out of contact with the source of the gaseous aluminizing species.
  • an apparatus for depositing a coating on the internal surfaces of hollow articles by gas deposition.
  • the apparatus includes a sheet metal enclosure having a manifold member which defines first and second chambers therein.
  • the first chamber is adapted to contain a powder mixture for generating a coating gas whereas the second chamber is adapted to house the articles being coated.
  • the manifold member includes hollow tubes or other connector means extending therethrough to connect the interior of the articles in gas flow relation to the first chamber where the coating gas is generated.
  • a source external of the enclosure supplies carrier gas to the first chamber at a controlled flow rate via tube means.
  • the carrier gas transports the coating gas generated in the first chamber through the manifold tubes and then into the internal passages of the articles to effect deposition.
  • the positive flow of coating gas through the internal passageways provides a substantially uniform coating thickness over the entire internal surface area of each article.
  • the gas flows needed for applying the internal coating may dilute the activity of the external source.
  • a microstructure such as a (PtNi)Al microstructure on a nickel-based superalloy may be formed. While this type of coating is adequate from a protection standpoint, it does not meet the specification requirements of gas turbine engine manufacturers.
  • the method of the present invention has two steps.
  • a simple aluminide coating is formed on internal surfaces of a part, such as a gas turbine engine component, by providing a first source of aluminum, heating the source of aluminum to obtain a gaseous aluminum species, and then flowing the gaseous aluminum species against, and through any passageway(s) defined by, the internal surfaces.
  • the flowing step comprises providing and maintaining a flow of an inert gas at a critical rate and at a pressure preferably of at least about 12.5 psi so as to cause said gaseous aluminum species to flow in the desired manner and form the simple aluminide coating.
  • the first source comprises a granular material containing from about 25 to about 50 wt% aluminum, and the balance consisting essentially of at least one material selected from the group consisting of iron, cobalt, nickel and chromium with at least about 1.0 wt% of a halide activator sprinkled on or in contact with the granules.
  • the second step of the method of the present invention comprises forming a PtAl 2 + NiAl, PtAl 2 + FeAl or PtAl 2 + CoAl coating on the outer surfaces of the part depending upon the composition of the superalloy used to form the part.
  • the coating is preferably formed by providing a second source of aluminum and heating the part and the second source to form a gaseous aluminizing species that coats the external or outer surfaces. Prior to coating the external surfaces, and preferably prior to coating the internal surfaces, a coating of a platinum group metal is deposited on the external surfaces of the part.
  • the external coating step is performed in the absence of any flow of inert gas.
  • the second source preferably comprises from about 45 to about 50 wt% of aluminum, the balance essentially cobalt with less than 1.0 wt.% of a halide activator sprinkled on or in contact with the granules.
  • the present invention relates to a method for coating a metal based alloy part, such as a gas turbine engine component, having internal surfaces defining at least one passageway and external surfaces.
  • the part may be formed from a nickel-based alloy, a cobalt-based alloy, or an iron-based alloy.
  • Figure 1 provides an overview of the method of the present invention.
  • a part to be treated or coated is first inspected, prepared, masked, plated with platinum, optionally heat treated to diffuse the platinum, and optionally remasked to protect areas not to be coated. These steps are all preferably carried out prior to the commencement of the actual coating operations.
  • the part may be prepared by degreasing it, blast cleaning it, and then rinsing it. Any suitable degreasing, blast cleaning and rinsing techniques known in the art may be used to prepare the part.
  • Platinum may be deposited on the part using any suitable technique known in the art. For example, platinum may be electroplated onto external surfaces of the part to a thickness of about 0.0003 inches. Thereafter, the part may be heat treated at about 1900°F for about three hours in an argon atmosphere to diffuse the platinum into the external surfaces of the part.
  • the heating chamber 12 has an upper chamber 17 and a lower chamber 15 separated by a wall 19. It also has one or more pins 14 upon which each of the parts 10 to be coated is mounted. When mounted on the pins, the parts 10 are positioned within the upper chamber 17. However, any internal passageways (40) in the parts are in communication with the lower chamber 15 via suitable passageways (not shown) in the pins 14. The internal passageways (40) in the parts are for the cooling air. In some components the cooling air is fed from the bottom and in this case the components are positioned vertically on the pins as indicated in Figure 3.
  • the cooling air is fed from the side.
  • the components are positioned horizontally on the pins (14).
  • Said pins may take the form of hollow tubes. Seals, such as seals 22, are provided to prevent the gaseous aluminizing species from leaking out of the bottom coating chamber.
  • a first source 16 of gaseous aluminizing species is positioned beneath the parts 10 in the lower chamber 15.
  • the source 16 is preferably a granular material having particle sizes in the range of from about 1/4 inch to about 1/2 inch with at least 1.0 wt% of a halide activator sprinkled on or in contact with the granules.
  • the granular material forming the source preferably has a composition of from about 25 to about 50 wt% aluminum and the balance consisting essentially of at least one material selected from the group consisting of iron, cobalt, nickel, chromium, and mixtures thereof.
  • the halide activator may be a fluoride, chloride, iodide or bromide such as aluminum fluoride, ammonium chloride, ammonium iodide, etc.
  • the heat chamber 12 also has an inlet 18 for allowing an inert gas to be introduced into the lower chamber 15 from an external source 20.
  • Suitable valve means 21 may be provided to regulate the flow rate of the inert gas entering the lower chamber 15.
  • the inlet 18, source 20 and valve means 21 may be arranged in an alternative location as shown in dotted lines in Figure 2. In this alternative arrangement, the inlet is connected to the lower chamber via conduit 23.
  • the critical flow is from about 0.5 cfh to 60 cfh at a pressure of 12.5 psi.
  • a flow rate of at least about 12.0 cfh.
  • the actual process for coating the internal surfaces and/or passageway(s) involves initiating a flow of inert gas into the chamber 15 at the critical flow rate and a pressure of 12.5 psi and applying heat to the chamber 12 so as to cause the generation of a gaseous aluminizing species from the source 16.
  • the heating step comprises heating the source to a temperature of about 1750°F to about 2150°F for a time period of one to fourteen hours. While the heat is being applied, the flow of the inert gas under the above conditions is maintained.
  • the flow of inert gas is stopped.
  • the chamber 12 is then opened and a second source 24 of gaseous aluminizing species is inserted into the upper chamber 17.
  • the first source 16 is left in place during this external coating step.
  • This second source is used to form the PtAl 2 + NiAl, PtAl 2 + FeAl, or PtAl 2 + CoAl coating on the exterior surfaces of the parts.
  • the second source 24 is positioned intermediate the parts 10.
  • the second source may comprise one or more source modules of material for creating the gaseous aluminizing species.
  • the second source 24 is also preferably a granular material having particle sizes in the range of from about 1/4 inch to about 1/2 inch with less than about 1.0 wt% of a halide activator sprinkled on or in contact with the granules.
  • the granular material forming the second source has a composition comprising from about 45 to about 50 wt% aluminum and the balance consisting essentially of cobalt.
  • the halide activator may be a fluoride and/or chloride such as aluminum fluoride.
  • the amount of halide activator within the material is determined by the aluminization time. For longer aluminization times, more activator is required.
  • External coating is accomplished by raising the temperature in the heat chamber back to a temperature in the range of about 1750°F to about 2150°F for a time in the range of from about 1 to about 14 hours.
  • a test was performed using a part fabricated from a DS Mar-M-200 + Hf material whose nominal composition was 9.0% Cr, 10.0% Co, 0.14% C, 2.0% Ti, 5.0% Al, 12.5% W, 0.015% B, 1.0% Cb, 1.6% Hf and the balance nickel.
  • the part had a number of internal surfaces forming a passageway.
  • the internal surfaces were coated using a source comprising 4 lbs of CoAl granules and 0.12 lbs of aluminum fluoride activator.
  • Argon was caused to flow into a heat chamber at a rate of 15 cfh at a pressure of 12.5 psi.
  • the part and the source were then heated, while the flow of argon was maintained, to a temperature of about 1900°F + 25°F for 3 hours.
  • the second source consisted of 8 lbs of CoAl granules and 0.008 lbs of aluminum fluoride activator. Argon was caused to flow into the chamber to maintain an inert gas atmosphere in the chamber; however, there was no forced flow of argon during this step. The part and the second source were heated to a temperature of about 1900°F + 25°F for 4 hours.
  • Figures 4 and 5 illustrate the coatings which were obtained.
  • Figure 4 clearly shows the formation of a PtAl 2 + NiAl protective layer.
  • Figure 5 illustrates the internal coating which is a simple aluminide coating.
  • the method of the present invention is advantageous in that it allows the formation of a highly desirable simple aluminide internal coating and the formation of a desirable PtAl 2 + NiAl, PtAl 2 + FeAl or PtAl 2 + CoAl external coating.
  • the method is further advantageous that it is economically viable and simple to perform.
EP96301522A 1995-03-07 1996-03-06 Verfahren zur Erzeugung einer Schutzdiffusionsschicht auf Legierungen auf Nickel-, Kobalt- und Eisenbasis Withdrawn EP0731187A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US399826 1990-05-04
US39982695A 1995-03-07 1995-03-07

Publications (1)

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EP0731187A1 true EP0731187A1 (de) 1996-09-11

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2310435A (en) * 1996-02-26 1997-08-27 Gen Electric High temperature alloy article with a discrete additive protective coating produced by aluminiding
GB2328219A (en) * 1997-07-12 1999-02-17 Mtu Muenchen Gmbh Process and apparatus for gas phase diffusion coating
EP1065293A1 (de) * 1999-06-30 2001-01-03 General Electric Company Verfahren zur Überwachung der Dicke und des Aluminiumgehalts von Aluminid-Diffusionsbeschichtungen
EP1445346A1 (de) * 2003-02-04 2004-08-11 General Electric Company Beschichtung aus Aluminid für Gasturbinenschaufel
EP1445345A1 (de) * 2003-02-04 2004-08-11 General Electric Company Beschichtung aus Aluminid für Gasturbinenschaufel
EP1524328A1 (de) * 2003-10-15 2005-04-20 General Electric Company Verfahren zur bereichsselektiven Dampfphasenaluminisierung
EP1790753A1 (de) * 2005-11-28 2007-05-30 Howmet Corporation Duplex Gasbeschichten
CN1721570B (zh) * 2004-03-16 2010-06-16 通用电气公司 用铝化物对空心物体涂层的方法
EP3202946A1 (de) * 2016-02-05 2017-08-09 United Technologies Corporation Formung einer aluminidbeschichtung mithilfe von metalllegierungskies

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1433497A (fr) * 1965-02-16 1966-04-01 Snecma Procédé de dépôt d'une couche protectrice sur une pièce métallique par une méthode en phase vapeur
FR2306276A1 (fr) * 1975-04-04 1976-10-29 Secr Defence Brit Procede et dispositif d'enduction par diffusion
US4148275A (en) * 1976-02-25 1979-04-10 United Technologies Corporation Apparatus for gas phase deposition of coatings
US4501776A (en) * 1982-11-01 1985-02-26 Turbine Components Corporation Methods of forming a protective diffusion layer on nickel, cobalt and iron base alloys
EP0349420A1 (de) * 1988-06-30 1990-01-03 Societe Nationale D'etude Et De Construction De Moteurs D'aviation "Snecma" Verfahren und Vorrichtung zum gleichzeitigen Schutz der inneren und äusseren Oberflächen, insbesondere bei der Aluminisierung von Teilen aus hitzebeständigen Legierungen auf der Basis von Ni, Co oder Fe
US5071678A (en) * 1990-10-09 1991-12-10 United Technologies Corporation Process for applying gas phase diffusion aluminide coatings
DE4119967C1 (de) * 1991-06-18 1992-09-17 Mtu Muenchen Gmbh

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1433497A (fr) * 1965-02-16 1966-04-01 Snecma Procédé de dépôt d'une couche protectrice sur une pièce métallique par une méthode en phase vapeur
FR2306276A1 (fr) * 1975-04-04 1976-10-29 Secr Defence Brit Procede et dispositif d'enduction par diffusion
US4148275A (en) * 1976-02-25 1979-04-10 United Technologies Corporation Apparatus for gas phase deposition of coatings
US4501776A (en) * 1982-11-01 1985-02-26 Turbine Components Corporation Methods of forming a protective diffusion layer on nickel, cobalt and iron base alloys
EP0349420A1 (de) * 1988-06-30 1990-01-03 Societe Nationale D'etude Et De Construction De Moteurs D'aviation "Snecma" Verfahren und Vorrichtung zum gleichzeitigen Schutz der inneren und äusseren Oberflächen, insbesondere bei der Aluminisierung von Teilen aus hitzebeständigen Legierungen auf der Basis von Ni, Co oder Fe
US5071678A (en) * 1990-10-09 1991-12-10 United Technologies Corporation Process for applying gas phase diffusion aluminide coatings
DE4119967C1 (de) * 1991-06-18 1992-09-17 Mtu Muenchen Gmbh

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2310435A (en) * 1996-02-26 1997-08-27 Gen Electric High temperature alloy article with a discrete additive protective coating produced by aluminiding
US5897966A (en) * 1996-02-26 1999-04-27 General Electric Company High temperature alloy article with a discrete protective coating and method for making
GB2310435B (en) * 1996-02-26 2000-03-22 Gen Electric High temperature alloy article with a discrete additive protective coating and method for making
GB2328219A (en) * 1997-07-12 1999-02-17 Mtu Muenchen Gmbh Process and apparatus for gas phase diffusion coating
US6120843A (en) * 1997-07-12 2000-09-19 Mtu Motoren- Und Turbinen-Union Muenchen Gmbh Method and apparatus for gas phase diffusion coating of workpieces made of heat resistant material
US6156123A (en) * 1997-07-12 2000-12-05 Mtu Motoren-Und Turbinen-Union Muenchen Gmbh Method and apparatus for gas phase diffusion coating of workpieces made of heat resistant material
GB2328219B (en) * 1997-07-12 2002-09-18 Mtu Muenchen Gmbh Process for the gas phase diffusion coating of workpieces of heat-resistant material with a coating material
EP1065293A1 (de) * 1999-06-30 2001-01-03 General Electric Company Verfahren zur Überwachung der Dicke und des Aluminiumgehalts von Aluminid-Diffusionsbeschichtungen
US6334907B1 (en) 1999-06-30 2002-01-01 General Electric Company Method of controlling thickness and aluminum content of a diffusion aluminide coating
SG91289A1 (en) * 1999-06-30 2002-09-17 Gen Electric Method of controlling thickness and aluminum content of a diffusion aluminide coating
EP1445346A1 (de) * 2003-02-04 2004-08-11 General Electric Company Beschichtung aus Aluminid für Gasturbinenschaufel
EP1445345A1 (de) * 2003-02-04 2004-08-11 General Electric Company Beschichtung aus Aluminid für Gasturbinenschaufel
US6929825B2 (en) 2003-02-04 2005-08-16 General Electric Company Method for aluminide coating of gas turbine engine blade
US7026011B2 (en) 2003-02-04 2006-04-11 General Electric Company Aluminide coating of gas turbine engine blade
SG120972A1 (en) * 2003-02-04 2006-04-26 Gen Electric Aluminide coating of gas turbine engine blade
SG125103A1 (en) * 2003-02-04 2006-09-29 Gen Electric Aluminide coating of gas turbine engine blade
EP1524328A1 (de) * 2003-10-15 2005-04-20 General Electric Company Verfahren zur bereichsselektiven Dampfphasenaluminisierung
CN1721570B (zh) * 2004-03-16 2010-06-16 通用电气公司 用铝化物对空心物体涂层的方法
EP1790753A1 (de) * 2005-11-28 2007-05-30 Howmet Corporation Duplex Gasbeschichten
US7371428B2 (en) 2005-11-28 2008-05-13 Howmet Corporation Duplex gas phase coating
EP3202946A1 (de) * 2016-02-05 2017-08-09 United Technologies Corporation Formung einer aluminidbeschichtung mithilfe von metalllegierungskies

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