US3849865A - Method of protecting the surface of a substrate - Google Patents

Method of protecting the surface of a substrate Download PDF

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US3849865A
US3849865A US00298156A US29815672A US3849865A US 3849865 A US3849865 A US 3849865A US 00298156 A US00298156 A US 00298156A US 29815672 A US29815672 A US 29815672A US 3849865 A US3849865 A US 3849865A
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percent
substrate
protecting
clad
metallic alloy
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M Gedwill
S Grisaffe
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National Aeronautics and Space Administration NASA
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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
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/02—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material
    • C23C28/021—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material including at least one metal alloy layer
    • 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
    • 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
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/02—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material
    • C23C28/023—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material only coatings of metal elements only
    • 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
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
    • C23C4/06—Metallic material
    • C23C4/073—Metallic material containing MCrAl or MCrAlY alloys, where M is nickel, cobalt or iron, with or without non-metal elements
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B21/00—Unidirectional solidification of eutectic materials
    • C30B21/02—Unidirectional solidification of eutectic materials by normal casting or gradient freezing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49826—Assembling or joining
    • Y10T29/49888—Subsequently coating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
    • Y10T428/12583—Component contains compound of adjacent metal
    • Y10T428/1259—Oxide

Definitions

  • aluminide conversion coatings alone offer less potential for providing long time oxidation and thermal fatigue resistance.
  • Nickel and cobalt base superalloys and dispersionstrengthened alloys are used as turbine vanes and blades in aircraft and land-based gas turbine engines. Oxidation, hot corrosion, and thermal fatigue cracking are major factors which limit the useful life of these ma-- terials. Aluminide coatings are used to extend the life of these superalloys by providing a more oxidation and hot corrosion resistant surface in which thermal fatigue cracking is reduced.
  • the aluminide coatings are in themselves made of a hard, brittle outer-layer and a hard, brittle multiphase sub-layer that can crack under high thermal stresses. Once cracked, the oxidizing and/or hot corrosion environment has direct access to the underlying substrate, and deleterious attacks can occur. Also certain elements in the superalloy substrate enter into these coatings. This generally reduces the environmental resistance of the coatings and makes them less ductile.
  • the substrate is initially overlayed with a ductile, oxidation resistant metallic alloy layer.
  • This overlay is achieved by foil cladding or other means, such as physical vapor deposition, ion plating, sputtering, plasma spraying, or slurry sintering.
  • Foil cladding requires more preliminary effort and fixturing, but it supplies a well characterized homogeneous material directly on the superalloy. Thus, a failsafe system is provided.
  • the aluminide outer layer has a tendency to be less embrittled by substrate elements. It has a lessened tendency to crack because it is supported by a ductile layer, not a brittle, multiphase layer that is conventionally the case. If a crack occurs in the aluminide outer-layer, the ductility of the underlayer restricts its propagation. Widespread oxida tion of the underlayer does not occur because the metallic underlayer is oxidation resistant.
  • Another object of the invention is to provide an aluminized coating having long time oxidation and thermal fatigue resistance for these materials.
  • a further object of the invention is to provide an im proved aluminized coating for nickel base and cobalt base superalloys, dispersion-strengthened alloys, composites, and directional eutectics.
  • a ductile, oxidation resistant metallic alloy is initially applied to the superalloy.
  • An aluminide coating is then applied to the metallic alloy.
  • NiCrAlSi and FeCrAlY foil claddings were applied to typical nickel and cobalt base superalloys of the type used in gas turbine engines.
  • the nominal composition of the first mentioned cladding was 15 to 25 percent chromium, 3' to 6 percent aluminum, 0.5
  • composition was 18 percent chromium, 4 percent aluminum, 1 percent-silicon, and the remainder nickel.
  • the other cladding had a nominal composition of 15 to 25 percent chromium, 3 to 6 percent aluminum, 0.1
  • the preferred composition was 25 percent chromium, 4 percent aluminum, l percent yttrium, and the remainder iron.
  • claddings were applied to nickel base superalloys known as IN-l00 and WI-52.
  • the nominal composition of the [N alloy was.15 percent cobalt, 9.5 percent chromium, 5.3 percent aluminum, 4.3 percent titanium, 3.2 percent molybdenum and the remainder nickel.
  • the nominal composition of the Wl-52 was 21 percent chromium, 11 percent tungsten, 2.2 percent iron, 1.9 percent columbium, 0.9 percent silicon and the remainder cobalt.
  • the claddings were also applied to WAZ-20 and NX-188 advanced superalloys and to The chemistry of the overlay coating is such that the oxidation resistance of the subsequently aluminized outermost layer is not seriously degraded.
  • the aluminide outer layer can be developed by pack cementa- TD-NiCr dispersion-strengthened alloy.
  • the nominal compositions were, for WAZ-ZO, 20 percent tungsten, 6.5 percent aluminum, 1.5 percent zirconium, 0.2 percent carbon and the remainder nickel; for NX-l88, 18 percent molybdenum, 8 percent aluminum, 0.04 percent carbon and the remainder nickel; and for TD-.
  • NiCr 20 percent chromium, 2 percent thorium dioxide, and the remainder nickel. It is further contemplated that the substrate can be nickel and cobalt base composites and directional eutectic alloys.
  • Claddings having a thickness of 0.127 millimeter of both materials were applied to the substrate specimens by hot isostatic gas pressure bonding at a helium pressure of 15,000 to 20,000 psi for 2 hours at I090C.
  • Aluminide coatings were then applied to the claddings by pack cementation at l,900 to 2,000F in argon using a powder mixture consisting of 1 percent sodium or amonium halide, 1 percent aluminum, and the remainder aluminum oxide.
  • the aluminide coating can be applied by a sintered or fused slurry, electrodeposition, physical vapor deposition, ion plating, sputtering, hot dipping, or pyrolysis.
  • the electrodeposition can be of the aqueous, fused salt, or electrophoresis type.
  • the spraying can be either a flame or plasma type.
  • the system performance was primarily evaluated on the basis of weight change, visual appearance, and metallographic change.
  • Weight change results of furnace tests on NiCrAlSi clad IN-100 and WI52 at l,090C for 20 hour exposure cycles were obtained. These tests showed that the clad-cladding alloy was oxidation resistant in that it gained weight in forming a protective oxide and then little further weight change occurred. While NiCrAlSi clad on IN-l showed a slight turnaround primarily due to spalling, it was more protective than on WI52. Both bare lN-IOO and bare WI-52 lost weight rapidly. Exposure at 1,040C resulted in more protective behavior for both cladding systems for times up to 400 hours.
  • NiCrAlSi cladding WI-52 showed considerable surface oxide penetration and internal oxidation in the cladding after only 120 hours of tests.
  • the FeCrAlY cladding was evaluated in cyclic furnace oxidation on IN-IOO and WI-52.
  • the l,090C weight change behavior of the clad WI-52 was almost identical to that of the cladding alloy itself.
  • the clad IN-lOO showed more rapid weight gains accompanied by significant spalling.
  • a lower exposure temperature of l,O40C resulted in less oxidation attack for the claddings on both substrates.
  • NiCrAlSi clad IN-IOO burner specimens were aluminized to obtain the benefits of both protective systems.
  • Soft ductile claddings had shown superior resistance to thermal fatigue cracking while harder and more brittle aluminide coatings resisted oxidation better.
  • Aluminizing the NiCrAlSi claddings produced a markedly improved protection system for lN-l00.
  • the system withstood at least 800 hours of Mach 1 burner rig testing at l,090C. Based on the time to show weight change turnaround, the aluminized cladding was four to five times as protective as the commercial aluminide coating. Its thermal fatigue resistance was about three times better than the aluminide coating.
  • the primary cause for improvement in thermal fatigue resistance is believed to be the existence of a rather ductile oxidation resistant layer of aluminum enriched cladding under the external aluminide coating.
  • Burner rig tests at l,090C and Mach-l were conducted on aluminized, electron beam melted and physical vapor deposited NiCrAlSi coatings on IN-l00 and NASA-TRW Vl-A.
  • the nominal composition on the coatings as-deposited is 15 percent chromium, 4 percent aluminum, 1 percent silicon, and the remainder nickel.
  • the nominal composition of NASA TRW-Vl-A superalloy is 7.5 percent cobalt, 6.0 percent chromium, 5.8 percent tungsten, 5.4 percent aluminum, 9.0 percent tantalum, 2.0 percent molybdenum, l.0 percent titanium, 0.5 percent columbium, 0.40 percent rhenium, 0.5 percent hafnium, 0.1 percent zirconium, O. I 3 percent carbon, 0.015 percent boron, and the remainder nickel. After hours of testing in the very severe environment, the specimens showed no evidence of thermal fatigue cracking and the coating had completely protected the superalloy substrates from oxidation and erosion.
  • claddings of NiCrAl containing one or more of Si, Y, Mn and Th can be used.
  • claddings of FeCrAl containing one or more of Y, Si, Mn and Ta can be used.
  • a method of protecting the surface of a substrate of a metallic base system selected from the group consisting of nickel and cobalt comprising the steps of cladding said surface with a ductile, oxidation resistant metallic alloy foil, and

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Abstract

The surface of a metallic base system is initially coated with a metallic alloy layer that is ductile and oxidation resistant. An aluminide coating is then applied to the metallic alloy layer. The chemistry of the metallic alloy layer is such that the oxidation resistance of the subsequently aluminized outermost layer is not seriously degraded.

Description

United States Patent [191 Gedwill et al.
[451 Nov. 26, 1974 METHOD OF PROTECTING THE SURFACE OF A SUBSTRATE [75] Inventors: Michael A. Gedwill, Lakewood;
Salvatore J. Grisaffe, Rocky River, both of Ohio [22] Filed: Oct. 16, 1972 [21] Appl. No.: 298,156
[52] US. Cl 29/460, 29/196.6, 29/197, 29/494, 29/497.5, 29/504 [51] Int. Cl B23p 3/00, B23p 19/04 [58] Field of Search 29/196.6, 197, 504, 494,
[56] References Cited UNITED STATES PATENTS 2,473,712 6/1949 Kinney 2 9/1966 X Sayre 29/494 X 3,367,022 2/1968 Hill i 29/504 X 3,647,517 3/1972 Milidantrl 29/l96.6 X
3,649,225 3/1972 Simmons 29/196.6 X 3,676,085 7/1972 Evans et al. 29/197 X Primary ExaminerChar1ie T. Moon Attorney, Agent, 'or Firm-G. E. Shook; N. T. Musial; J. R. Manning 5 7 ABSTRACT The surface of a metallic base system is initially coated with a metallic alloy layer that is ductile and oxidation resistant. An aluminide coating is then ap plied to the metallic alloy layer. The chemistry of the metallic alloy layer is such that the oxidation resistance of the subsequently aluminized outermost layer is not seriously degraded.
10 Claims, No Drawings METHOD OF PROTECTING THE SURFACE OF A SUBSTRATE ORIGIN OF THE INVENTION The invention described herein was made by employees of the United States Government and may be manufactured and used by or for the Government for governmental purposes without the payment of any royalties thereon or therefor.
BACKGROUND OF THE INVENTION fluence on coating chemistry, thickness, and properties. Thus, it is difficult to tailor an aluminide coating to resist a particular engine environment. As engine temperatures increase to improve performance, aluminide conversion coatings alone offer less potential for providing long time oxidation and thermal fatigue resistance.
Nickel and cobalt base superalloys and dispersionstrengthened alloys are used as turbine vanes and blades in aircraft and land-based gas turbine engines. Oxidation, hot corrosion, and thermal fatigue cracking are major factors which limit the useful life of these ma-- terials. Aluminide coatings are used to extend the life of these superalloys by providing a more oxidation and hot corrosion resistant surface in which thermal fatigue cracking is reduced.
The aluminide coatings are in themselves made of a hard, brittle outer-layer and a hard, brittle multiphase sub-layer that can crack under high thermal stresses. Once cracked, the oxidizing and/or hot corrosion environment has direct access to the underlying substrate, and deleterious attacks can occur. Also certain elements in the superalloy substrate enter into these coatings. This generally reduces the environmental resistance of the coatings and makes them less ductile.
SUMMARY OF THE INVENTION According to the present invention the substrate is initially overlayed with a ductile, oxidation resistant metallic alloy layer. This overlay is achieved by foil cladding or other means, such as physical vapor deposition, ion plating, sputtering, plasma spraying, or slurry sintering. Foil cladding requires more preliminary effort and fixturing, but it supplies a well characterized homogeneous material directly on the superalloy. Thus Thus, a failsafe system is provided. The aluminide outer layer has a tendency to be less embrittled by substrate elements. It has a lessened tendency to crack because it is supported by a ductile layer, not a brittle, multiphase layer that is conventionally the case. If a crack occurs in the aluminide outer-layer, the ductility of the underlayer restricts its propagation. Widespread oxida tion of the underlayer does not occur because the metallic underlayer is oxidation resistant.
OBJECTS OF THE INVENTION It is, therefore, an object of the present invention to provide an improved oxidation resistant coating for superalloys and dispersion-strengthened alloys.
Another object of the invention is to provide an aluminized coating having long time oxidation and thermal fatigue resistance for these materials.
A further object of the invention is to provide an im proved aluminized coating for nickel base and cobalt base superalloys, dispersion-strengthened alloys, composites, and directional eutectics.
These and other objects of the invention will be apparent from the specification which follows.
PREFERRED EMBODIMENT OF THE INVENTION According to the present invention a ductile, oxidation resistant metallic alloy is initially applied to the superalloy. An aluminide coating is then applied to the metallic alloy.
In order to illustrate the beneficial technical effects of the invention NiCrAlSi and FeCrAlY foil claddings were applied to typical nickel and cobalt base superalloys of the type used in gas turbine engines. The nominal composition of the first mentioned cladding was 15 to 25 percent chromium, 3' to 6 percent aluminum, 0.5
'to 1.5 percent silicon, and the remainder nickel. The
preferred composition was 18 percent chromium, 4 percent aluminum, 1 percent-silicon, and the remainder nickel.
The other cladding had a nominal composition of 15 to 25 percent chromium, 3 to 6 percent aluminum, 0.1
. to 1 percent yttrium, and the remainder iron. The preferred composition was 25 percent chromium, 4 percent aluminum, l percent yttrium, and the remainder iron.
These claddings were applied to nickel base superalloys known as IN-l00 and WI-52. The nominal composition of the [N alloy was.15 percent cobalt, 9.5 percent chromium, 5.3 percent aluminum, 4.3 percent titanium, 3.2 percent molybdenum and the remainder nickel. The nominal composition of the Wl-52 was 21 percent chromium, 11 percent tungsten, 2.2 percent iron, 1.9 percent columbium, 0.9 percent silicon and the remainder cobalt. The claddings were also applied to WAZ-20 and NX-188 advanced superalloys and to The chemistry of the overlay coating is such that the oxidation resistance of the subsequently aluminized outermost layer is not seriously degraded. The aluminide outer layer can be developed by pack cementa- TD-NiCr dispersion-strengthened alloy. The nominal compositions were, for WAZ-ZO, 20 percent tungsten, 6.5 percent aluminum, 1.5 percent zirconium, 0.2 percent carbon and the remainder nickel; for NX-l88, 18 percent molybdenum, 8 percent aluminum, 0.04 percent carbon and the remainder nickel; and for TD-.
NiCr, 20 percent chromium, 2 percent thorium dioxide, and the remainder nickel. It is further contemplated that the substrate can be nickel and cobalt base composites and directional eutectic alloys.
Claddings having a thickness of 0.127 millimeter of both materials were applied to the substrate specimens by hot isostatic gas pressure bonding at a helium pressure of 15,000 to 20,000 psi for 2 hours at I090C. Aluminide coatings were then applied to the claddings by pack cementation at l,900 to 2,000F in argon using a powder mixture consisting of 1 percent sodium or amonium halide, 1 percent aluminum, and the remainder aluminum oxide. It is also contemplated that the aluminide coating can be applied by a sintered or fused slurry, electrodeposition, physical vapor deposition, ion plating, sputtering, hot dipping, or pyrolysis. The electrodeposition can be of the aqueous, fused salt, or electrophoresis type. The spraying can be either a flame or plasma type.
The system performance was primarily evaluated on the basis of weight change, visual appearance, and metallographic change. Weight change results of furnace tests on NiCrAlSi clad IN-100 and WI52 at l,090C for 20 hour exposure cycles were obtained. These tests showed that the clad-cladding alloy was oxidation resistant in that it gained weight in forming a protective oxide and then little further weight change occurred. While NiCrAlSi clad on IN-l showed a slight turnaround primarily due to spalling, it was more protective than on WI52. Both bare lN-IOO and bare WI-52 lost weight rapidly. Exposure at 1,040C resulted in more protective behavior for both cladding systems for times up to 400 hours.
Metallographic cross sections of the NiCrAlSi cladding on IN-l00 showed this system was relatively unef fected by 200 hour cyclic furnace oxidation at l,090C. NiCrAlSi clad WI-52 showed considerable surface oxide penetration and internal oxidation in the cladding after only 120 hours of tests.
The FeCrAlY cladding was evaluated in cyclic furnace oxidation on IN-IOO and WI-52. The l,090C weight change behavior of the clad WI-52 was almost identical to that of the cladding alloy itself. The clad IN-lOO, however, showed more rapid weight gains accompanied by significant spalling. A lower exposure temperature of l,O40C resulted in less oxidation attack for the claddings on both substrates.
Metallographic and weight change data obtained after l,090C furnace tests on the commercial aluminide coatings were compared with similar data with the most protective claddings on each substrate. These comparisons indicated that both the attack on the microstructure and weight changes of the coating and Ni- CrAlSi cladding on IN-IOO were very similar after 200 hours hour cycles) at l,090C/Here, both protection systems were approximately the same thickness. The FeCrAlY cladding on WI-b 52 was in much better condition than the completely degraded coating, but it was about twice as thick in the as-clad condition. This ease in controlling thickness is a beneficial technical effect of the overlay or cladding process.
The most promising cladding systems based on furnace testing were the NiCrAlSi clad IN-lOO and the FeCrAlY clad WI-52; FeCrAlY clad IN-IOO also appeared to have some 'potential. These systems were subjected to Mach 1 burner rig testing at both I,040 and l,090C using 1 hour exposure cycles followed by air blast quenching. Such testing imposed significantly greater thermal stress on the protection system and the surface oxide, especially at the leading edges of the burner rig specimens. The FeCrAlY cladding perfortned better on both IN-IOO and WI-52 than did the NiCrAlSi cladding. The thermal fatigue resistance of these clad systems was markedly superior to that of the aluminide coated systems. In all tests, no cracks were observed in the claddings within the test times. Only the FeCrAlY clad WI-52 performed better in oxidation erosion than the aluminide coating.
Some NiCrAlSi clad IN-IOO burner specimens were aluminized to obtain the benefits of both protective systems. Soft ductile claddings had shown superior resistance to thermal fatigue cracking while harder and more brittle aluminide coatings resisted oxidation better. Aluminizing the NiCrAlSi claddings produced a markedly improved protection system for lN-l00. The system withstood at least 800 hours of Mach 1 burner rig testing at l,090C. Based on the time to show weight change turnaround, the aluminized cladding was four to five times as protective as the commercial aluminide coating. Its thermal fatigue resistance was about three times better than the aluminide coating.
The primary cause for improvement in thermal fatigue resistance is believed to be the existence of a rather ductile oxidation resistant layer of aluminum enriched cladding under the external aluminide coating.
In conventional aluminide coatings on superalloys, a hard, carbide rich zone is typically found here. Benefits may also be derived from the conversion of the relatively simple NiCrAlSi alloy to the aluminide. This aluminide would be expected to contain little of the strengthening elements found in the IN-l00.
Several aluminized NiCrAlSi clad WAZ-ZO, NX-l 88, and TD-NiCr specimens were tested in cyclic furnace oxidation at 1,l50C to see how effective the coating would be for higher temperature applications. The oxidation life of the clad was well in excess of 500 and 300 hours, respectively, on WAZ-ZO and NX-l 88, and slightly more than 600 hours on TD-NiCr. A substantial improvement over aluminide coatings alone on these substrates which generally failed well within hours in the same tests.
Burner rig tests at l,090C and Mach-l were conducted on aluminized, electron beam melted and physical vapor deposited NiCrAlSi coatings on IN-l00 and NASA-TRW Vl-A. The nominal composition on the coatings as-deposited is 15 percent chromium, 4 percent aluminum, 1 percent silicon, and the remainder nickel. The nominal composition of NASA TRW-Vl-A superalloy is 7.5 percent cobalt, 6.0 percent chromium, 5.8 percent tungsten, 5.4 percent aluminum, 9.0 percent tantalum, 2.0 percent molybdenum, l.0 percent titanium, 0.5 percent columbium, 0.40 percent rhenium, 0.5 percent hafnium, 0.1 percent zirconium, O. I 3 percent carbon, 0.015 percent boron, and the remainder nickel. After hours of testing in the very severe environment, the specimens showed no evidence of thermal fatigue cracking and the coating had completely protected the superalloy substrates from oxidation and erosion.
While several preferred embodiments of the invention have been described it is contemplated that various modifications may be made without departing from the spirit of the invention or the scope of the subjoined claims. By way of example, claddings of NiCrAl containing one or more of Si, Y, Mn and Th can be used. Also claddings of FeCrAl containing one or more of Y, Si, Mn and Ta can be used.
What is claimed is:
1. A method of protecting the surface of a substrate of a metallic base system selected from the group consisting of nickel and cobalt comprising the steps of cladding said surface with a ductile, oxidation resistant metallic alloy foil, and
aluminizing the outermost surface portion of said foil thereby forming an outer aluminide coating thereon.
2. A method of protecting the surface of a substrate as claimed in claim 1 wherein the substrate comprises a nickel-base material selected from the group consisting of superalloys, dispersion-strengthened alloys, composites, and directional eutectic alloys.
3. A method of protecting the surface of a substrate as claimed in claim 1 wherein the substrate comprises a cobalt-base material selected from the group consisting of superalloys, dispersion-strengthened alloys, composites, and directional eutectic alloys.
4. A method of protecting the surface of a substrate as claimed in claim 1 wherein the substrate is clad with a NiCrAlSi metallic alloy foil having a nominal compo- V sition of about 18 percent chromium, about 4 percent aluminum, about 1 percent silicon and the remainder nickel.
6. A method of protecting the surface of a substrate as claimed in claim 1 wherein the substrate is clad with a FeCrAlY metallic alloy foil having a nominal composition in the range from about 15 percent to about 25 percent chromium, from about 3 percent to about 6 percent aluminum, from about 0.1 percent to about 1 percent yttrium. I
7. A method of protecting the surface of a substrate as claimed in claim 6 wherein the substrate is clad with a FeCrAlY metallic alloy foil having a nominal composition of about 25 percent chromium, about 4 percent aluminum, about 1 percent yttrium, and the remainder iron.
8. A method of protecting the surface of a superalloy substrate as claimed in claim 1 wherein the metallic alloy foil is applied to the surface of the substrate by solid state bonding.
9. A method of protecting the surface of a substrate as claimed in claim 1 wherein foil cladding is applied by hot isostatic gas pressure bonding.
10. A method of protecting the surface of a superalloy substrate as claimed in claim 1 wherein the outer aluminide coating is applied by pack cementation in ar-

Claims (10)

1. A METHOD OF PROTECTING THE SURFACE OF A SUBSTRATE OF A METALLIC BASE SYSTEM SELECTED FROM THE GROUP CONSISTING OF NICKEL AND COBALT COMPRISING THE STEPS OF CLADDING SAID SURFACE WITH A DUCTILE, OXIDATION RESISTANT METALIC ALLOY FOIL, AND ALUMINIZING THE OUTERMOST SURFACE PORTION OF SAID FOIL THEREBY FORMING AN OUTER ALUMINIDE CONTAINING THEREON.
2. A method of protecting the surface of a substrate as claimed in claim 1 wherein the substrate comprises a nickel-base material selected from the group consisting of superalloys, dispersion-strengthened alloys, composites, and directional eUtectic alloys.
3. A method of protecting the surface of a substrate as claimed in claim 1 wherein the substrate comprises a cobalt-base material selected from the group consisting of superalloys, dispersion-strengthened alloys, composites, and directional eutectic alloys.
4. A method of protecting the surface of a substrate as claimed in claim 1 wherein the substrate is clad with a NiCrAlSi metallic alloy foil having a nominal composition in the range from about 15 percent to about 25 percent chromium, from about 3 percent to about 6 percent aluminum, from about 0.5 percent to about 1.5 percent silicon, and the remainder nickel.
5. A method of protecting the surface of a substrate as claimed in claim 4 wherein the substrate is clad with a NiCrAlSi metallic alloy foil having a nominal composition of about 18 percent chromium, about 4 percent aluminum, about 1 percent silicon and the remainder nickel.
6. A method of protecting the surface of a substrate as claimed in claim 1 wherein the substrate is clad with a FeCrAlY metallic alloy foil having a nominal composition in the range from about 15 percent to about 25 percent chromium, from about 3 percent to about 6 percent aluminum, from about 0.1 percent to about 1 percent yttrium.
7. A method of protecting the surface of a substrate as claimed in claim 6 wherein the substrate is clad with a FeCrAlY metallic alloy foil having a nominal composition of about 25 percent chromium, about 4 percent aluminum, about 1 percent yttrium, and the remainder iron.
8. A method of protecting the surface of a superalloy substrate as claimed in claim 1 wherein the metallic alloy foil is applied to the surface of the substrate by solid state bonding.
9. A method of protecting the surface of a substrate as claimed in claim 1 wherein foil cladding is applied by hot isostatic gas pressure bonding.
10. A method of protecting the surface of a superalloy substrate as claimed in claim 1 wherein the outer aluminide coating is applied by pack cementation in argon.
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Cited By (26)

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FR2338386A1 (en) * 1976-01-13 1977-08-12 United Technologies Corp SUPERALLY ARTICLE COVERED WITH AN INTERMEDIATE ALUMINUM COATING AND AN EXTERNAL COATING OF THE MCRALY TYPE
FR2370106A1 (en) * 1976-11-04 1978-06-02 Gen Electric PROCESS FOR IMPROVING THE RESISTANCE TO OXIDATION AND TO HOT CORROSION OF SUPERALALLIES
US4218007A (en) * 1979-02-22 1980-08-19 General Electric Company Method of diffusion bonding duplex sheet cladding to superalloy substrates
DE3010608A1 (en) * 1979-05-29 1980-12-11 Howmet Turbine Components COATING COMPOSITION FOR NICKEL, COBALT AND IRON CONTAINING SUPER ALLOY AND SUPER ALLOY COMPONENT
US4339509A (en) * 1979-05-29 1982-07-13 Howmet Turbine Components Corporation Superalloy coating composition with oxidation and/or sulfidation resistance
US4837928A (en) * 1986-10-17 1989-06-13 Cominco Ltd. Method of producing a jumper chip for semiconductor devices
US4904542A (en) * 1988-10-11 1990-02-27 Midwest Research Technologies, Inc. Multi-layer wear resistant coatings
EP0386386A1 (en) * 1989-03-06 1990-09-12 United Technologies Corporation Process for producing Yttrium enriched aluminide coated superalloys
US5129574A (en) * 1991-02-19 1992-07-14 Grumman Aerospace Corporation Braze bonding of oxidation-resistant foils
USRE34173E (en) * 1988-10-11 1993-02-02 Midwest Research Technologies, Inc. Multi-layer wear resistant coatings
EP0532255A1 (en) * 1991-09-13 1993-03-17 General Electric Company Thermal barrier coating
US5366136A (en) * 1992-05-27 1994-11-22 Societe Nationale D'etude Et De Construction De Moteurs D'aviation "Snecma" Process for forming a coating on a superalloy component, and the coated component produced thereby
US5512382A (en) * 1995-05-08 1996-04-30 Alliedsignal Inc. Porous thermal barrier coating
US5562998A (en) * 1994-11-18 1996-10-08 Alliedsignal Inc. Durable thermal barrier coating
US5967755A (en) * 1995-07-25 1999-10-19 Siemens Aktiengesellschaft Product with a metallic basic body and method for manufacturing a product
EP1013786A1 (en) * 1998-12-22 2000-06-28 GE Aviation Services Operation (Pte) Ltd. Method for repairing a superalloy turbine component
US6103386A (en) * 1994-11-18 2000-08-15 Allied Signal Inc Thermal barrier coating with alumina bond inhibitor
US6224963B1 (en) 1997-05-14 2001-05-01 Alliedsignal Inc. Laser segmented thick thermal barrier coatings for turbine shrouds
EP1123987A1 (en) * 2000-02-11 2001-08-16 General Electric Company Repairable diffusion aluminide coatings
US6482537B1 (en) 2000-03-24 2002-11-19 Honeywell International, Inc. Lower conductivity barrier coating
US6585864B1 (en) 2000-06-08 2003-07-01 Surface Engineered Products Corporation Coating system for high temperature stainless steel
US6673467B2 (en) 2001-10-01 2004-01-06 Alstom (Switzerland) Ltd Metallic component with protective coating
US20060057418A1 (en) * 2004-09-16 2006-03-16 Aeromet Technologies, Inc. Alluminide coatings containing silicon and yttrium for superalloys and method of forming such coatings
WO2006052277A3 (en) * 2004-09-16 2007-02-15 Aeromet Technologies Inc Gas turbine engine components with aluminide coatings and method of forming such aluminide coatings on gas turbine engine components
US20080096045A1 (en) * 2004-12-13 2008-04-24 Aeromet Technologies, Inc. Turbine Engine Components With Non-Aluminide Silicon-Containing and Chromium-Containing Protective Coatings and Methods of Forming Such Non-Aluminide Protective Coatings
US20090166204A1 (en) * 2002-09-11 2009-07-02 George Edward Creech Corrosion-resistant layered coatings

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Cited By (38)

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Publication number Priority date Publication date Assignee Title
FR2338386A1 (en) * 1976-01-13 1977-08-12 United Technologies Corp SUPERALLY ARTICLE COVERED WITH AN INTERMEDIATE ALUMINUM COATING AND AN EXTERNAL COATING OF THE MCRALY TYPE
FR2370106A1 (en) * 1976-11-04 1978-06-02 Gen Electric PROCESS FOR IMPROVING THE RESISTANCE TO OXIDATION AND TO HOT CORROSION OF SUPERALALLIES
US4218007A (en) * 1979-02-22 1980-08-19 General Electric Company Method of diffusion bonding duplex sheet cladding to superalloy substrates
DE3010608A1 (en) * 1979-05-29 1980-12-11 Howmet Turbine Components COATING COMPOSITION FOR NICKEL, COBALT AND IRON CONTAINING SUPER ALLOY AND SUPER ALLOY COMPONENT
US4313760A (en) * 1979-05-29 1982-02-02 Howmet Turbine Components Corporation Superalloy coating composition
US4339509A (en) * 1979-05-29 1982-07-13 Howmet Turbine Components Corporation Superalloy coating composition with oxidation and/or sulfidation resistance
US4837928A (en) * 1986-10-17 1989-06-13 Cominco Ltd. Method of producing a jumper chip for semiconductor devices
USRE34173E (en) * 1988-10-11 1993-02-02 Midwest Research Technologies, Inc. Multi-layer wear resistant coatings
US4904542A (en) * 1988-10-11 1990-02-27 Midwest Research Technologies, Inc. Multi-layer wear resistant coatings
EP0386386A1 (en) * 1989-03-06 1990-09-12 United Technologies Corporation Process for producing Yttrium enriched aluminide coated superalloys
US5129574A (en) * 1991-02-19 1992-07-14 Grumman Aerospace Corporation Braze bonding of oxidation-resistant foils
EP0532255A1 (en) * 1991-09-13 1993-03-17 General Electric Company Thermal barrier coating
US5236745A (en) * 1991-09-13 1993-08-17 General Electric Company Method for increasing the cyclic spallation life of a thermal barrier coating
US5366136A (en) * 1992-05-27 1994-11-22 Societe Nationale D'etude Et De Construction De Moteurs D'aviation "Snecma" Process for forming a coating on a superalloy component, and the coated component produced thereby
US5476723A (en) * 1992-05-27 1995-12-19 Societe Nationale D'etude Et De Construction De Motors D'aviation "S.N.E.C.M.A." Coated superalloy component
US6103386A (en) * 1994-11-18 2000-08-15 Allied Signal Inc Thermal barrier coating with alumina bond inhibitor
US5562998A (en) * 1994-11-18 1996-10-08 Alliedsignal Inc. Durable thermal barrier coating
US6395343B1 (en) 1994-11-18 2002-05-28 Alliedsignal Durable thermal barrier coating
US5512382A (en) * 1995-05-08 1996-04-30 Alliedsignal Inc. Porous thermal barrier coating
US5624721A (en) * 1995-05-08 1997-04-29 Alliedsignal Inc. Method of producing a superalloy article
US5967755A (en) * 1995-07-25 1999-10-19 Siemens Aktiengesellschaft Product with a metallic basic body and method for manufacturing a product
US6156133A (en) * 1995-07-25 2000-12-05 Siemens Aktiengesellschaft Method for manufacturing a product with a metallic basic body
US6224963B1 (en) 1997-05-14 2001-05-01 Alliedsignal Inc. Laser segmented thick thermal barrier coatings for turbine shrouds
EP1013786A1 (en) * 1998-12-22 2000-06-28 GE Aviation Services Operation (Pte) Ltd. Method for repairing a superalloy turbine component
EP1123987A1 (en) * 2000-02-11 2001-08-16 General Electric Company Repairable diffusion aluminide coatings
US6482537B1 (en) 2000-03-24 2002-11-19 Honeywell International, Inc. Lower conductivity barrier coating
US6585864B1 (en) 2000-06-08 2003-07-01 Surface Engineered Products Corporation Coating system for high temperature stainless steel
US6673467B2 (en) 2001-10-01 2004-01-06 Alstom (Switzerland) Ltd Metallic component with protective coating
US20090166204A1 (en) * 2002-09-11 2009-07-02 George Edward Creech Corrosion-resistant layered coatings
WO2006036171A1 (en) * 2004-09-16 2006-04-06 Aeromet Technologies, Inc. Superalloy jet engine components with protective coatings and method of forming such protective coatings on superalloy jet engine components
WO2006052277A3 (en) * 2004-09-16 2007-02-15 Aeromet Technologies Inc Gas turbine engine components with aluminide coatings and method of forming such aluminide coatings on gas turbine engine components
US20080220165A1 (en) * 2004-09-16 2008-09-11 Aeromet Technologies, Inc. Gas Turbine Engine Components With Aluminide Coatings And Method Of Forming Such Aluminide Coatings On Gas Turbine Engine Components
US20080274290A1 (en) * 2004-09-16 2008-11-06 Aeromet Technologies, Inc. Metal Components With Silicon-Containing Protective Coatings Substantially Free of Chromium and Methods of Forming Such Protective Coatings
US20060057418A1 (en) * 2004-09-16 2006-03-16 Aeromet Technologies, Inc. Alluminide coatings containing silicon and yttrium for superalloys and method of forming such coatings
US7901739B2 (en) 2004-09-16 2011-03-08 Mt Coatings, Llc Gas turbine engine components with aluminide coatings and method of forming such aluminide coatings on gas turbine engine components
US8623461B2 (en) 2004-09-16 2014-01-07 Mt Coatings Llc Metal components with silicon-containing protective coatings substantially free of chromium and methods of forming such protective coatings
US20080096045A1 (en) * 2004-12-13 2008-04-24 Aeromet Technologies, Inc. Turbine Engine Components With Non-Aluminide Silicon-Containing and Chromium-Containing Protective Coatings and Methods of Forming Such Non-Aluminide Protective Coatings
US9133718B2 (en) 2004-12-13 2015-09-15 Mt Coatings, Llc Turbine engine components with non-aluminide silicon-containing and chromium-containing protective coatings and methods of forming such non-aluminide protective coatings

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