US3716398A - Impact resistant coatings for nickel-base and cobalt-base superalloys and the like - Google Patents

Impact resistant coatings for nickel-base and cobalt-base superalloys and the like Download PDF

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Publication number
US3716398A
US3716398A US00065147A US3716398DA US3716398A US 3716398 A US3716398 A US 3716398A US 00065147 A US00065147 A US 00065147A US 3716398D A US3716398D A US 3716398DA US 3716398 A US3716398 A US 3716398A
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Prior art keywords
pack
aluminum
nickel
weight
coating
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US00065147A
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English (en)
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R Stueber
S Klach
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Chromalloy Gas Turbine Corp
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Chromalloy American Corp
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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
    • C23C10/28—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
    • C23C10/34—Embedding in a powder mixture, i.e. pack cementation
    • C23C10/36—Embedding in a powder mixture, i.e. pack cementation only one element being diffused
    • C23C10/48—Aluminising
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • 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
    • C23C10/28—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
    • C23C10/34—Embedding in a powder mixture, i.e. pack cementation
    • C23C10/52—Embedding in a powder mixture, i.e. pack cementation more than one element being diffused in one step
    • C23C10/54—Diffusion of at least chromium
    • C23C10/56—Diffusion of at least chromium and at least aluminium
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
    • 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.]
    • Y10T428/12736—Al-base component
    • Y10T428/1275—Next to Group VIII or IB metal-base component

Definitions

  • ABSTRACT In the production of impact and oxidation resistant 21 A l.N 65 147 l 1 pp 0 nickel-base metal coatings on heat resistant superal- 1 loys by pack aluminizingin which nickel aluminide is [52] US. Cl. ..l17/107.2 P, 117/131, 29/197 f d to id h protective coating, markedly [51] I111.
  • Some of these well-known techniques involved embedding the article to be coated (or otherwise covering the surface thereof) in powdered coating pack including a powdered source of the coating material (with or without admixture with powdered inert filler) and a vaporizable halogen carrier ingredient (such as a heat-volatile halide), and heating the thus embedded article and pack in a sealed retort (or other controlled, and generally non-oxidizing atmosphere)'to an elevated temperature at which the carrier material vaporizes and/orotherwise reacts with or functions as a carrier for transporting the coating material from or throughthe powderedpack to the surface of the article to be coated for diffusion or other reaction thereat.
  • a powdered source of the coating material with or without admixture with powdered inert filler
  • a vaporizable halogen carrier ingredient such as a heat-volatile halide
  • the various chemical reactions involved e.g., between the carrier and the coating material, and the metal or other components of the article to be coated, among whatever ingredients are in the pack, between coating'material and whatever intermetallics or alloys may have already been formed at or in the surface of the article being coated, etc.
  • the various chemical reactions involved occur more or less simultaneouslyduring the heating treatment and are mostly of a reversible nature, so that the net result of the coatingstep andthe chemical reactions therein 'involvedmay depend predominantly upon the various equilibria achieved.
  • ingredients in the coating pack may be inclined to combine with each other at the same time (and, perhaps, evenat the same rate) as one or another thereof may diffuse into the surface of the metal article; while (if the equilibrium conditions are appropriate) some portion of the metal from the article itself, or one of another component thereof, may also diffuse out of the article and into the pack ingredients.
  • a buffering material such as chromium
  • the diffusion of which into the surface of the article can only occur at a diminished rate (or, perhaps, cannot occur at all) at the desired treating temperatures, the availability or transfer of the aluminum component in the pack for diffusion'into the surface of 'the article is readily. inhibited or controlled so that the temperature levels or other thermodynamic conditions necessary to break down the preliminary chromium aluminide sufficiently for aluminum to be diffused will produce the desired conditions for the formation of the particular nickel aluminide desired in the surface of the article.
  • an inhibiting or rate controlling component such as chromium in an aluminum pack for preliminary formation therein of a chromium aluminide has been calcia, silica, zirconia and the like. It was noted that the ratio of chromium to aluminum in thepack may range up to 8 and, more preferably, from about 0.5 to 4.6
  • a composition found particularly'satisfactory for commercial use is one containing by weight 69% alumina as the inert diluent, 22% chromium, 8% aluminum and l% ammonium fluoride, with the coating layer or casing depths of the order of about 0.0019 inch to0.0022 inch. 1n producing the coating, the pack is enclosed in a sealed container and heated at between 1,800 to 2,lF for 4 to hours, with the temperature and time ranging more broadly from about 1,400
  • Another object is to provide a pack aluminizing process for producing a nickelaluminide coating of uniform thickness capable of sustaining severe plastic deformation, such as that resulting from impact without cracking or spalling.
  • Still another object is to provide a pack aluminizing process for producing a ductile nickel aluminide coating which will permit the base metal substrate to be strained during use into its plastic range while undergoing heavy loading or thermal stress without the coating cracking or spalling.
  • the improvement residing in controlling the amount of aluminum in the pack over the range of about one-eighth to not more than 5 percent by weight of the pack.
  • the coating produced by the aforementioned process has a uniform thickness and can sustain severe plastic deformation, such as that resulting from impact, without cracking or spalling in such a way as to affect adversely the sulfidation and oxidation resistance of the coating.
  • the ductility of coatings produced in accordance with the invention permits the base metal substrate to be strained into its plastic range while undergoing heavy loading or thermal stress with the result that the coating does not crack or spall.
  • a wide range of nickel-base alloys can be coated using the foregoing method.
  • a typical alloy composition range is one containing by weight of up to about Cr, e.g. 5% to 30% Cr, up to about 20% ofa metal from the group consisting of Mo and W, up to about 10% of a metal from the group consisting of Cb and Ta, up to about 1% C (preferably up to about 0.5%), up to about 10% by weight of a metal from the group consisting of Ti and Al, the total amount of Ti and Al not exceeding about 12%, up tO about 20% Fe, up to about 2% Mn, up to about 2% Si, up to about 0.2% B, up to about 1% Zr, up to about 2% Hf, and the balance at least about by weight of nickel.
  • Examples of known alloys falling within the aforementioned range are nickel-base alloys referred to by designations Mar-M-246, lN- 738, IN-792 Udimet 500, Mar-M-432, ln-7l3, Mar-M-200, 8-1900, TRW- 6A, lN-600 and Udimet 700, and cobalt-basealloys,
  • a set of doublenested retorts is used in which the inner and outer retorts are glass sealed to inhibit the entry of air during the coating process.
  • single retorts may be used as well.
  • the pack is freshly prepared and then prereacted by heating the pack to a temperature of, for example, 1,800" to 2,200F for about 1 to 20 hours, the pre-reacted powder being then screened and used as the pack into which the article to be coated is then embedded.
  • the pack composition may range by weight from about 5 to 40 percent chromium, or to 30% chromium, about one-eighth to not more than 5% aluminum, 'a small but effective amount of a halogen material-energizer (e.g. from about one-eighth to l or 2 percent) and the balance a diluent material, e.g. such refractory oxides as alumina, zirconia, calcia, silica, and the like.
  • the diffusion coating treatment is carried out at a temperature of about l,400 to' 2,200F for about %to 40 hours.
  • a pack cementation treatment found particularly advantageous in coating alloys of Table l is l,900F for about 25 hours at temperature, using a blended powder pack composition containing chromium, 2% aluminum, about ammonium bifluoride and the balance essentially alumina.
  • a drop weight test is employed in which a metal weight (e.g..a half-pound weight) with a projection or indenter having a 0.065 inch radius at its impact end is dropped upon a coated test piece from various heights measured in inches, the impact value being determined in inchpounds at. the point where the coating fails by cracking orspalling.
  • Alloys coated from a pack containing by weight 20% chromium, 3% aluminum, ammonium'bifluoride and the balance essentially alumina resulted in impact values (ductile coating) of over 17 inch pounds (high impact resistant), while thesamepack containing 8% by weight of aluminum resulted in inferior impact values (brittle coating) as low as 3 inch pounds.
  • the improved ductility of the coating enables the coating to deform as the base metal substrate is strained due to applied load orthermal stress arising in the environment of use, such as airfoils, in jet engines.
  • This ability of the coating to deform with fracture with applied stress such as might arise from thermal shock, protects the-base metal against catastrophic oxidation or hot corrosion.
  • load-induced strain of the base metal in the elastic range resulted in severe cracking of the coating.
  • Example 1 V A series of pack cementation compositions was tested in which the aluminum in the pack was varied from about one-eighth to 8 percent by weight with the chromium level at about 20 percent. The pack also contained about NH FHF and the balance alumina. The tests were carried out on a series of commercial nickel-base alloys, the compositions of which are given in Table 1. Test pieces of each alloy were em bedded in the pack in a sealed retort which pack had first been pre-reacted (as described hereinbefore) and the coating step carried out at 1,900F for 25 hours. Following the coating, the test pieces were brushed clean and then subjected to the impact test described hereinbefore.
  • the resulting coatings varied in thickness from about 1.2 to 5 mils (0.0012 to 0.005 inch) and seemed to relate directly to the amount of aluminum powder'in the pack. Thus, the thinnest coating was obtained at the lower range, while the 5 mil thickness was obtained with the pack containing 8% aluminum.
  • the coatings which exhibited optimum impact values of over 17 inch pounds and which were ductile were obtained in pack compositions containing not more than 5 percent aluminum. At aluminum contents in the pack of over 5 percent, that is, over 6, 7 and up to 8 percent, the coatings were brittle and exhibited impact values as low as 3 inch pounds.
  • the results obtained in the aforementioned tests are given in Table 2.
  • the impact specimen was coated in a powder mixture containing 20"/o Cr, 3 /o Al, Ai /o NH FHF and the balance A1 0 and the specimen removed from the powder pack and impact tested. The impact value was greater than 17 inch pounds. The same specimen was subsequently coated again in a powder mixture of the same composition, removed and impact tested. The result was an impact value of greater than 17 inch pounds.
  • Metallographic inspection of the coating on this specimen revealedv a case depth of 5.1 mils (0.0051 inch).
  • si il tests d d using a k tai i accordance with the invention exhibited good oxidachromium, /4% NH FHF, from 1 to 3% aluminum tion resistance in excess of 400 hours at 2,000F.
  • the P composition may range -by weight broadly The values of over 17 inch pounds reported for the from about 5 Percent to 40 Percent chromium, about tests on coatings within the invention means that no 175% to more: than 5% aluminum, about to 1 1 spalling or cracking occurred when the half-pound 2% hahde ohetglzet -gabout 4 and the w i ht was did f m a h ight f 34 in h ,5 x 34 balance essentially a refractory oxide diluent, e.g. alu- 17 i h d h li i f h apparatus However, mina.
  • the chromium may at an aluminum composition in the pack of 8 percent, be controlled from about 7 to percent and the alu- I the coating was very brittle and gave a reading of 3 inch ththum from about 1/5 Pa to 215%- we have found pounds, thus indicating that the coatings of the inven- It advantageous m Wotkthg over the foregoing ranges to i are over fivetimes bettcr i f as impact 30 employ a chromium to aluminum ratio of about 4:1 to sistance is concerned using the drop test as the V 160:1 and, more advantageously, about 8:1 to 100:1. criterion.
  • cracking of the g) began at the relatively g providing said alloy having a composition containing level of about 35 inch pounds (optimum impact reb i h up to about 30% C up to about 20% f sistance) with the impact value beginning to fall off at a metal f m h group consisting f Mo and w up above 26% aluminum and thereafter at a fairly rapid to about 10% of meta] f the group consisting rate at just below 5% aluminum pack concentration.
  • f Cb d T up to about 1% C, up to about 10% From below 5% aluminum to about 6 percent and 7% by weight of a metal from the group consisting of aluminum pack concentration, the falling off in impact Ti and Al, the total amount of Ti and Al not exresistance is sharp and reaches a very low level of ceeding about 12%, up to about 20% Fe, up to between 2% to 3 inch pounds at 8% aluminum concenabout 2% Mn, up to about 2% Si, up to about 0.2% tration.
  • the B up to about 1% Zr, up to about 2% Hf, and the coating has good ductility and exhibits relatively high balance at least about 45% by weight of nickel; impact values, the optimum impact values being preparing an aluminum-containing pack consisting achieved about 292% aluminum concentration and entially by weight of about 5 to 0% r u below, that is, advantageously from about a to 2%% n effective amount of aluminum not exceeding 3 aluminum c n tration, percent, a small but effective amount of a halide
  • Prereacting Said P y heating Said P at a NH,FHF and Al,0;,,the balance) showed that no Petatul'e g g from about 1,3000 ⁇ : to ki occurred when the alloy was loaded and embedding a nickel

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  • Chemical & Material Sciences (AREA)
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  • Metallurgy (AREA)
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US00065147A 1970-08-19 1970-08-19 Impact resistant coatings for nickel-base and cobalt-base superalloys and the like Expired - Lifetime US3716398A (en)

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US (1) US3716398A (fr)
JP (1) JPS535255B1 (fr)
CA (1) CA923768A (fr)
CH (1) CH541630A (fr)
DE (1) DE2128736C3 (fr)
FR (1) FR2102357B1 (fr)
GB (1) GB1331136A (fr)
IL (2) IL36735A0 (fr)
IT (1) IT945895B (fr)
SE (1) SE367442B (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3978251A (en) * 1974-06-14 1976-08-31 International Harvester Company Aluminide coatings
US4043945A (en) * 1974-11-11 1977-08-23 Hitachi, Ltd. Method of producing thin layer methanation reaction catalyst
US4142023A (en) * 1975-12-16 1979-02-27 United Technologies Corporation Method for forming a single-phase nickel aluminide coating on a nickel-base superalloy substrate
WO2005106064A1 (fr) * 2004-04-28 2005-11-10 Diffusion Alloys Limited Revetements pour aubes de turbine

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5217757A (en) * 1986-11-03 1993-06-08 United Technologies Corporation Method for applying aluminide coatings to superalloys

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3073015A (en) * 1960-05-16 1963-01-15 Chromalloy Corp Diffusion coating of metals
US3096205A (en) * 1960-05-16 1963-07-02 Chromalloy Corp Diffusion coating of metals
US3257230A (en) * 1964-03-24 1966-06-21 Chromalloy American Corp Diffusion coating for metals
US3436249A (en) * 1966-02-23 1969-04-01 Rolls Royce Aluminising powder
US3544348A (en) * 1968-10-25 1970-12-01 United Aircraft Corp Overhaul process for aluminide coated gas turbine engine components

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1273888A (fr) * 1960-04-14 1961-10-20 Chromalloy Corp Article métallique pourvu d'un revêtement et son procédé de production
FR1566639A (fr) * 1968-03-26 1969-05-09

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3073015A (en) * 1960-05-16 1963-01-15 Chromalloy Corp Diffusion coating of metals
US3096205A (en) * 1960-05-16 1963-07-02 Chromalloy Corp Diffusion coating of metals
US3257230A (en) * 1964-03-24 1966-06-21 Chromalloy American Corp Diffusion coating for metals
US3436249A (en) * 1966-02-23 1969-04-01 Rolls Royce Aluminising powder
US3544348A (en) * 1968-10-25 1970-12-01 United Aircraft Corp Overhaul process for aluminide coated gas turbine engine components

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3978251A (en) * 1974-06-14 1976-08-31 International Harvester Company Aluminide coatings
US4043945A (en) * 1974-11-11 1977-08-23 Hitachi, Ltd. Method of producing thin layer methanation reaction catalyst
US4142023A (en) * 1975-12-16 1979-02-27 United Technologies Corporation Method for forming a single-phase nickel aluminide coating on a nickel-base superalloy substrate
WO2005106064A1 (fr) * 2004-04-28 2005-11-10 Diffusion Alloys Limited Revetements pour aubes de turbine
US20080057189A1 (en) * 2004-04-28 2008-03-06 John Smith Coatings For Turbine Blades
US7824738B2 (en) 2004-04-28 2010-11-02 Diffusion Alloys Limited Coatings for turbine blades

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DE2128736A1 (de) 1972-03-02
IL36735A0 (en) 1971-06-23
GB1331136A (en) 1973-09-19
DE2128736B2 (de) 1978-11-09
DE2128736C3 (de) 1979-07-12
IL36735A (en) 1974-03-14
CA923768A (en) 1973-04-03
SE367442B (fr) 1974-05-27
IT945895B (it) 1973-05-10
FR2102357B1 (fr) 1974-03-29
FR2102357A1 (fr) 1972-04-07
JPS535255B1 (fr) 1978-02-25
CH541630A (fr) 1973-09-15

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