GB2159838A - Surface strengthening of overlay coatings - Google Patents
Surface strengthening of overlay coatings Download PDFInfo
- Publication number
- GB2159838A GB2159838A GB08513942A GB8513942A GB2159838A GB 2159838 A GB2159838 A GB 2159838A GB 08513942 A GB08513942 A GB 08513942A GB 8513942 A GB8513942 A GB 8513942A GB 2159838 A GB2159838 A GB 2159838A
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- GB
- United Kingdom
- Prior art keywords
- coating
- ceramic
- thickness
- mils
- overlay
- Prior art date
- 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.)
- Granted
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- 238000000576 coating method Methods 0.000 title claims abstract description 66
- 238000005728 strengthening Methods 0.000 title description 4
- 239000011248 coating agent Substances 0.000 claims abstract description 48
- 238000005524 ceramic coating Methods 0.000 claims abstract description 20
- 239000000463 material Substances 0.000 claims abstract description 14
- 238000000034 method Methods 0.000 claims abstract description 14
- 239000000919 ceramic Substances 0.000 claims description 20
- 239000000758 substrate Substances 0.000 claims description 15
- 239000000203 mixture Substances 0.000 claims description 12
- 230000008901 benefit Effects 0.000 claims description 8
- 230000000694 effects Effects 0.000 claims description 6
- 229910052759 nickel Inorganic materials 0.000 claims description 6
- 229910000601 superalloy Inorganic materials 0.000 claims description 6
- 229910052804 chromium Inorganic materials 0.000 claims description 5
- 229910052727 yttrium Inorganic materials 0.000 claims description 5
- 230000001464 adherent effect Effects 0.000 claims description 4
- 230000004888 barrier function Effects 0.000 claims description 3
- 229910002076 stabilized zirconia Inorganic materials 0.000 claims 2
- 229910052684 Cerium Inorganic materials 0.000 claims 1
- 229910052746 lanthanum Inorganic materials 0.000 claims 1
- 229910052706 scandium Inorganic materials 0.000 claims 1
- 238000007788 roughening Methods 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 19
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 10
- 239000007789 gas Substances 0.000 description 10
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 8
- 230000003647 oxidation Effects 0.000 description 6
- 238000007254 oxidation reaction Methods 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 239000012720 thermal barrier coating Substances 0.000 description 6
- 229910010293 ceramic material Inorganic materials 0.000 description 5
- 230000007613 environmental effect Effects 0.000 description 5
- 238000007750 plasma spraying Methods 0.000 description 5
- 238000007740 vapor deposition Methods 0.000 description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 230000003746 surface roughness Effects 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 239000011229 interlayer Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000001627 detrimental effect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 238000002294 plasma sputter deposition Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000011253 protective coating Substances 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 description 2
- 229910000951 Aluminide Inorganic materials 0.000 description 1
- 241000588731 Hafnia Species 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005269 aluminizing Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 1
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000001010 compromised effect Effects 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- CJNBYAVZURUTKZ-UHFFFAOYSA-N hafnium(IV) oxide Inorganic materials O=[Hf]=O CJNBYAVZURUTKZ-UHFFFAOYSA-N 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229910002077 partially stabilized zirconia Inorganic materials 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000004901 spalling Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 229910001233 yttria-stabilized zirconia Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
- 229910052845 zircon Inorganic materials 0.000 description 1
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
-
- 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
- C23C4/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/12—Blades
- F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
- F01D5/288—Protective coatings for blades
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Coating By Spraying Or Casting (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
Abstract
Coatings, methods for applying coatings, and coated articles are described. The coatings are of the overlay type and are resistant to rumpling in service. The coatings comprise an initial layer of an MCrAlY material and a thin strong ceramic coating securely bonded to the surface of the overlay coating. The ceramic coating strengthens the surface of the overlay coating and helps to resist surface roughening which would otherwise occur in service.
Description
SPECIFICATION
Surface strengthening of overlay coatings
This invention relates to the field of coatings for superalloy substrates. The coating and the coated articles described in the present application are useful in high temperature environments including gas turbine engines at extremes of temperature and stress. Through the use of the present invention substantial increases in useful coating life are possible.
Superalloys are widely used particularly in gas turbine engines. The demands placed on superalloys in modern gas turbine engines require that they be given a protective coating in order to adequately resist the environment to which they are exposed for a useful period of time. Overlay coatings consist of a metallic layer which is applied to the substrate. One used family of overlay coatings is that referred to as MCrAIY coatings where M is a metal selected from the group consisting of nickel and cobalt and mixtures thereof. Patents describing coatings of this type include U.S.
Patent Nos. 3 542 530, 3 676 085, 3754903 and 3928026.
By their nature, overlay coatings are optimized to resist environmental attack, namely oxidation and hot corrosion. The compositions which lend themselves to providing the requisite oxidation and corrosion resistance are generally not particularly strong and it has not generally been recognized that strength is an important coating requirement since it has generally been thought that the substrate material provides the strength while the coating material provides the environmental protection. However, it has been observed in certain situations that where turbine engines are operated at extremes of temperature and stress strains that the prior art coating material appears to flow and form a surface pattern referred to as rumpling consisting of alternating peaks and valleys.This phenomenon can occur early in the service and it is a serious problem since it reduces the effectiveness of the articles and can reduce engine efficiency.
Rumpling is detrimental in several respects.
First, the valleys in the coating represent areas of reduced thickness where environmental attack can rapidly affect the substrate. Secondly, the peaks in the coating interfere with the gas flow and can result in local increases in metal temperature which can increase the rate of attack. Thirdly, the surface area of the coating is increased which can lead to more rapid depletion of protective elements. And finally, the roughened surface can lead to fatigue crack initiation.
Attempts have been made to address this problem through the development of stronger coatings but these attempts have not been successful since all attempts to produce stronger coatings have compromised the environmental resistance of the coating.
In a related area, increasing development efforts have been aimed at the production of so-called thermal barrier coatings. These are coatings usually of a ceramic material which provide a thermal insulating effect thereby reducing the temperature of the underlying substrate and/or coating. Such coatings can also benefit the oxidation resistance of the substrate and/or coating even though most thermal barrier coatings are permeable to corrosive gases. The corrosion and oxidation benefit from thermal barrier coatings arises from the fact that the thermal barrier coating can reduce the metal temperature by as much as 111"C (200 F) thereby substantially reducing the rate of attack. Prior art patents dealing with thermal barrier coatings include U.S.
Patent Nos. 3 091 548, 4055 705, 4 095 003, 4 248 940, 4 269 903, 4321 310,4328285 and 4335190. Some of these patents describe the application of thin ceramic coatings to overlay coatings and may for example include ceramic thicknesses on the order of from 25.4 to 1270 ym (1 to 50 mils). However, from consideration of the specification and examples in these patents it is clear that these are broad ranges and not reflective of the preferred ranges which would be used by one seeking the true thermal barrier (insulative) effect.
In prior art thermal barrier coatings, the ceramic thickness is usually greater than the
MCrAIY or bond coat thickness. In the present invention the ceramic thickness will usually be less than the MCrAIY or bond coat thickness.
To the knowledge of the inventors it has not heretofore been appreciated that a thin ceramic coating on an overlay coating can strengthen the surface of the overlay coating and prevent its deformation and flow under extremes of temperature and stress without producing any significant thermal barrier benefit.
The present invention comprises a surface strengthened coating system which can protect metal articles from environmental attack particularly under conditions of high temperature and high stress. The coating system includes an initial overlay layer of an MCrAIY coating on the substrate having a thickness of from about 76.2 ym to about 254 lim, (about 3 to about 10 mils) and a thin ceramic layer on the overaly layer having a thickness of from about 7.62 to about 101.6 m (0.3 to about 4 miles), preferably from 12.7,um to 76.2 m (0.5 to 3.0 mils), and most preferably from 12.7 to 50.8 ,zm (0,5 to 2.0 mils).
The ceramic outer coating strengthens the surface of the overlay coating preventing rumpling in service even after extended periods of time.
Other features and advantages will be apparent from the specification and claims and from the accompanying drawing which illus trates an embodiment of the invention.
The Figure is a graph showing the surface roughness of a coating produced according to the present invention and a coating produced according to the prior art as a function of time at temperature.
The invention coating consists of a metallic layer of an MCrAIY composition having a continuous adherent thin ceramic layer on its outer surface. The broad composition for the
MCrAIY is 10-30% Cr, 5-15% Al, 0.01 to 1 % Y (or Hf, Ln, Ce, Sc, and mixtures thereof) with M, the balance being selected from the group consisting of Co, Ni and mixtures thereof. Minor amounts of other elements such as silicon may also be used without departing from the scope of the invention.
Such alloys are known in the prior art for use alone as protective coatings and are described in various U.S. patents including 3542 530, 3 676 085, 3754903 and 3928026.
This invention also contemplates the possible use of various interlayers between the superalloy substrate and the MCrAIY layer and in particular it is known from U.S. Patent No.
4005 989 that the provision of an aluminide layer (produced by pack aluminizing) between the substrate and an MCrAIY layer can provide improved coating durability. Other materials such as platinum have also been proposed for interlayer use. Of course, such interlayers will only be used where necessary and only where they do not adversely affect the bond between the substrate and the MCrAIY coating.
The MCrAIY layer may be applied by vapor deposition, plasma spraying or sputtering. Vapor deposition has the advantage of producing a smooth surface although recent advances in plasma spraying can also provide a usefully smooth surface. Sputtering will also produce a smooth surface. It is known to use a variety of post coating treatments in order to improve the properties of the MCrAIY coating including peening and heat treatment.
As an optional, though preferred next step, the MCrAIY layer can be oxidized to produce an alumina surface layer. Such oxidation can be performed in air at a temperature of between about 260"C and 1093"C (500' and 2000"F). We have used hydrogen atmosphere at a temperature of about 1080"C (about 1975"F) for about four hours. The use of a commercially pure hydrogen atmosphere appears to produce a desirable oxide coating by virtue of the inherent oxygen impurities in the atmosphere.
Following the application of the MCrAIY coating and the optional oxidation step, the thin ceramic surface layer can be applied. We have employed partially stabilized zirconia as the surface ceramic coating material. The selection of zirconia has been based in part upon the relatively low thermal conductivity of zirconia. We believe, however, that other ceramic materials will produce an equivalent result. The ceramic layer must be adherent to the MCrAIY coating and adherence is believed to require in part some solid solubility between alumina which is the native oxide forming on the MCrAIY layer and the surface ceramic material. The zirconia employed to date has been partially stabilized with either yttria or magnesia in order to eliminate the detrimental phase transformation which would otherwise occur in the use temperature range.
Other ceramics which may be employed include alumina, ceria, mullite, zircon, silica, silicon nitride, hafnia and certain zirconates, borides and nitrides.
It must be emphasized that the function of the ceramic layer is one of strength rather than thermal insulation. The thickness of the ceramic layer is so slight that the thermal advantage resulting from the layer is negligible, typically on the order of 28"C (50"F). The strengthening effect has been observed to persist even after spallation of the ceramic (resulting from application process defects) has left only thin residue of the ceramic on the MCrAIY coating.
The ceramic coating can be applied by a variety of techniques including plasma spraying, sputtering and vapor deposition. Plasma spraying is a preferred technique mainly from an economic standpoint. Sputtering and vapor deposition can under some situations both produce structures containing defects or cracks extending from the substrate to the surface of the coating. It is a surprising observation that even coatings with such numerous defects are effective in strengthening the surface of the overlay coating. It is theorized that the relative percentage of the surface area exposed to the cracks is slight and that each island of ceramic material is firmly bonded to the overlay coating and is effective in eliminating the surface flow and rumpling which would otherwise occur.
The present invention will be better understood through consideration of the following illustrative example. Samples of a nickel base superalloy were given a 1 27 ym (5 mil) coating of a NiCoCrAIY material having a nominal composition of 20% Co, 18% Cr, 12% Al, 0.4% Y and balance Ni. This material was applied by vapor deposition in accordance with the teachings of U.S. Patent
No. 3 928 026. The coated articles were vapor blasted and were then heat treated at 1080"C (1975"F) for 4 hours consistent with commerical practice: during this heat treatment an alumina layer formed on the surface.
One of the bars was then given a 25.4 m, (1 mil) coating of yttria stabilized zirconia (7% yttria) using a plasma spray technique. Material was provided in the form of 0.037 mm (- 400 mesh) powder and was sprayed from a high energy plasma gun in a plasma spraying apparatus operated at a pressure between 98.7 kPa and 1 3.3 kPa (one atmosphere and 100 mm of Hg); the feed input to the gun was 40 volts, 900 amps, 5.66 m3 (200 cubic fee) of argon gas and 40 grams/minute of the ceramic powder.The part being coated was maintained at a temperature of less than 316"C (600"F). After coating, the surface roughness of the samples was measured and was found to be for the case of the MCrAIY material about 1.27 zm (50 microinches) (arthmetic average) and in the case of the ceramic coated material about 1.90 cm (75 microinches) (arithmetic average). These samples were then tested in a burner rig which produced an open flame which heated the material to a temperature of about 1163 C (2125 F) using the following temperature cycle 1163 C (2125 F)/2 minutes
+ 1010"C (1850"F)/10 minutes + force air cool for 2 minutes.Since the bars were not internally air cooled, the thermal effect of the ceramic coating was negligible. The Figure shows the comparative roughness of the two samples as a function of exposure time. It can be seen that the sample coated with only the
MCrAIY material went from a surface roughness of 1.27 jum (50 microinches) to a surface roughness of about 15.87 jilm (625 microinches) in 1400 hours, an increase of about 12X. In contrast the ceramic coated sample went from a starting surface finish of 1.90 m (75 microinches) to a final finish of 5.08 ym (200 microinches) in the same period of time, an increase of less than 3X.
In another evaluation two turbine blades were prepared and engine tested. The blades had a nominal composition of 9% Cr, 10%
Co, 12% W, 1% Nb, 2% Ti, 5% Al, 0.015%
B, 2% Hf, balance nickel and had an MCrAIY layer 127 m (5 mils) in thickness, of a nominal composition of 18% Cr, 23% Co, 12.5% Al, 0.3%Y, balance nickel, applied in accordance with the teachings of U.S. Patent
No. 3 928026. One of the blades then received 50.8 ism (2 mil) thick coating of zirconia stabilized with 7% yttrium using a previously described plasma spray coating process.
These two blades were tested in a JT9D-7Q gas turbine engine having a thrust capability of about 21792 kg (48,000 pounds). The test consisted of a series of cycles simulating severe commerical service. The cycles were performed at a rate of about 1000 cycles in about 1 50 hours and the maximum gas temperature was about 1538"C (2800"F). Periodic inspections were made and it was found that the blade having only the overlay coating had failed in about 2,000 cycles. After 2,000 cycles the substrate surface was partially exposed and had started to oxidize. After 2,000 cycles the blade having the invention coating had not failed. The ceramic coating was intact and there was no visual indication of attack of the overlying MCrAIY coating.
Thus it can be seen that the provision of a thin ceramic layer having a trivial thermal insulating effect can reduce the relative degree of rumpling by at least 4X.
In a third evaluation of the invention two sample bars were prepared following the same procedure described with regard to the initial illustrative example. One had a ceramic coating thickness of 76.2 ,cm (3 mils) while the other had a ceramic coating thickness of 101.6 ym (4 mils). Testing was performed following the procedure described with respect to the first example. This testing sequence is representative of the conditions to be found in a modern high performance commercial gas turbine engine, e.g., a first turbine blade applications. The 76.2 ym (3 mil) coated sample withstood 1100 hours of testing with no spalling of the ceramic material and testing was discontinued at this time. The 101.6 ym (4 mil) coated sample displayed a significant spallation in 250 hours of testing.
Thus, in a severe gas turbine engine environment 101.6 jim (4 mils) appears to be the upper limit for coating thickness if spallation is to be avoided.
It should be understood that the invention is not limited to the particular embodiments shown and described herein, but that various changes and modifications may be made without departing from the scope of this novel concept as defined by the following claims.
Claims (14)
1. A coated article characterized in comprising
a. a superalloy substrate
b. an MCrAIY overlay coating on at least a portion of the substrate
c. a thin durable adherent ceramic coating on at least a portion of the overlay coating said ceramic coating being effective in reducing coating rumpling without providing a significant thermal barrier effect.
2. A coated article according to claim 1 characterized in that the MCrAIY overlay coating has a composition consisting essentially of 10-30% Cr, 5-15% Al, 0.01-1% of a material selected from the group consisting of Y,
La, Ce, Sc and mixtures thereof, balance selected from the group consisting of Ni, Co and mixtures thereof.
3. A coated article according to claim 1 characterized in that the MCrAIY overlay coating has a thickness of from about 76.2 to about 254 ym (about 3 to about 10 mils).
4. A coated article according to claim 1 characterized in that the ceramic coating has a thickness of from about 7.62 to about 101.6 pm (about 0.3 to about 4 mils).
5. A coated article according to claim 1 characterized in that the ceramic coating has a thickness of from about 12.7-76.2,um (0.5-3.0 mils).
6. A coated article according to claim 1 characterized in that the ceramic coating has a thickness of from about 12.7-50.8 pm (0.5-2.0 mils).
7. A coated article according to claim 1 characterized in that the thermal benefit resulting from the ceramic layer is less than about 28"C (50"F).
8. A coated article according to claim 1 characterized in that the ceramic is essentially stabilized zirconia.
9. A method for reducing rumpling in overlay coated substrates characterized in that it comprises applying a thin durable adherent ceramic coating to the overlay coating.
10. A method according to claim 9, characterized in that the ceramic coating has a thickness of from about 7.62 to about 101.6 ym (0.3 to about 4 mils).
11. A method according to claim 9, characterized in that the ceramic coating has a thickness of from about
12.7-76.2 ,um (0.5-3.0 mils).
1 2. A method according to claim 9 characterized in that the ceramic coating has a thickness of from about 12.7-50.8 itm (0.5-2.0 mils).
1 3. A method according to claim 9, characterized in that the thermal advantage from the ceramic coating is less than about 28"C (50 F).
14. A method according to claim 19, characterized in that the ceramic is essentially stabilized zirconia.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US61879684A | 1984-06-08 | 1984-06-08 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8513942D0 GB8513942D0 (en) | 1985-07-03 |
| GB2159838A true GB2159838A (en) | 1985-12-11 |
| GB2159838B GB2159838B (en) | 1987-04-08 |
Family
ID=24479179
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08513942A Expired GB2159838B (en) | 1984-06-08 | 1985-06-03 | Surface strengthening of overlay coatings |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS613875A (en) |
| BE (1) | BE902581A (en) |
| BR (1) | BR8502550A (en) |
| FR (1) | FR2565525B1 (en) |
| GB (1) | GB2159838B (en) |
| IL (1) | IL75304A (en) |
| SG (1) | SG54587G (en) |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0236520A1 (en) * | 1984-09-10 | 1987-09-16 | Hitachi, Ltd. | Ceramic-coated, heat-resisting member and process for preparing the same |
| EP0266299A2 (en) * | 1986-10-30 | 1988-05-04 | United Technologies Corporation | Thermal barrier coating system |
| GB2199849A (en) * | 1987-01-16 | 1988-07-20 | Rolls Royce Plc | Treatment of superalloy surfaces |
| EP0288156A1 (en) * | 1987-03-24 | 1988-10-26 | BAJ Limited | Overlay coating |
| GB2218113A (en) * | 1986-12-12 | 1989-11-08 | Vapor Technologies Inc | A method of protecting ceramic bodies against mechanical and thermal action. |
| GB2226050A (en) * | 1988-12-16 | 1990-06-20 | United Technologies Corp | Thin abradable ceramic air seal |
| FR2651774A1 (en) * | 1989-09-08 | 1991-03-15 | United Technologies Corp | CERAMIC MATERIAL AND INSULATING COATING BASED ON THIS MATERIAL. |
| GB2243161A (en) * | 1990-04-17 | 1991-10-23 | Gen Electric | Coating systems for titanium oxidation protection |
| GB2252567A (en) * | 1991-02-11 | 1992-08-12 | Inst Elektroswarki Patona | Metal/ceramic protective coating for superalloy articles |
| WO1996034128A1 (en) * | 1995-04-25 | 1996-10-31 | Siemens Aktiengesellschaft | Metal substrate with an oxide layer and an anchoring layer |
| EP0780484A1 (en) * | 1995-12-22 | 1997-06-25 | General Electric Company | Thermal barrier coated articles and method for coating |
| GB2317400A (en) * | 1996-09-19 | 1998-03-25 | Toshiba Kk | Thermal barrier coating providing reaction sintering suppression |
| WO2002092874A1 (en) * | 2001-05-15 | 2002-11-21 | Tohoku Techno Arch Co., Ltd. | Member coated with thermal barrier coating film and thermal spraying powder |
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| US4055705A (en) * | 1976-05-14 | 1977-10-25 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Thermal barrier coating system |
| WO1981001983A1 (en) * | 1980-01-07 | 1981-07-23 | United Technologies Corp | Columnar grain ceramic thermal barrier coatings on polished substrates |
| WO1981001982A1 (en) * | 1980-01-07 | 1981-07-23 | United Technologies Corp | Columnar grain ceramic thermal barrier coatings |
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| US3269856A (en) * | 1962-06-07 | 1966-08-30 | Lockheed Aircraft Corp | Coating for refractory metal |
| FR1431769A (en) * | 1965-02-01 | 1966-03-18 | Comp Generale Electricite | Process for the protection of metals and alloys |
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| US3955038A (en) * | 1973-04-09 | 1976-05-04 | Sandvik Aktiebolag | Hard metal body |
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| US4248940A (en) * | 1977-06-30 | 1981-02-03 | United Technologies Corporation | Thermal barrier coating for nickel and cobalt base super alloys |
| US4124737A (en) * | 1976-12-30 | 1978-11-07 | Union Carbide Corporation | High temperature wear resistant coating composition |
| JPS53138905A (en) * | 1977-05-12 | 1978-12-04 | Kawasaki Steel Co | Blast furnace exit |
| DE2842848C2 (en) * | 1977-10-17 | 1987-02-26 | United Technologies Corp., Hartford, Conn. | Material for covering objects |
| JPS55113870A (en) * | 1979-02-26 | 1980-09-02 | Toshiba Corp | Forming method for heat resistant coating layer |
| JPS5662956A (en) * | 1979-10-15 | 1981-05-29 | United Technologies Corp | Corrosion and abrasion resistant coating material |
| US4328285A (en) * | 1980-07-21 | 1982-05-04 | General Electric Company | Method of coating a superalloy substrate, coating compositions, and composites obtained therefrom |
| JPS5852469A (en) * | 1981-09-24 | 1983-03-28 | Nippon Kokan Kk <Nkk> | Exhaust valve for diesel engine |
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1985
- 1985-05-24 IL IL75304A patent/IL75304A/en unknown
- 1985-05-28 BR BR8502550A patent/BR8502550A/en not_active IP Right Cessation
- 1985-06-03 GB GB08513942A patent/GB2159838B/en not_active Expired
- 1985-06-04 BE BE0/215127A patent/BE902581A/en not_active IP Right Cessation
- 1985-06-05 FR FR8508477A patent/FR2565525B1/en not_active Expired
- 1985-06-05 JP JP60122367A patent/JPS613875A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US4055705A (en) * | 1976-05-14 | 1977-10-25 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Thermal barrier coating system |
| WO1981001983A1 (en) * | 1980-01-07 | 1981-07-23 | United Technologies Corp | Columnar grain ceramic thermal barrier coatings on polished substrates |
| WO1981001982A1 (en) * | 1980-01-07 | 1981-07-23 | United Technologies Corp | Columnar grain ceramic thermal barrier coatings |
Cited By (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0236520A1 (en) * | 1984-09-10 | 1987-09-16 | Hitachi, Ltd. | Ceramic-coated, heat-resisting member and process for preparing the same |
| EP0266299A2 (en) * | 1986-10-30 | 1988-05-04 | United Technologies Corporation | Thermal barrier coating system |
| EP0266299A3 (en) * | 1986-10-30 | 1989-05-31 | United Technologies Corporation | Thermal barrier coating system |
| GB2218113A (en) * | 1986-12-12 | 1989-11-08 | Vapor Technologies Inc | A method of protecting ceramic bodies against mechanical and thermal action. |
| GB2199849A (en) * | 1987-01-16 | 1988-07-20 | Rolls Royce Plc | Treatment of superalloy surfaces |
| GB2199849B (en) * | 1987-01-16 | 1991-05-15 | Rolls Royce Plc | Superalloy surface treatment against vapourisation |
| EP0288156A1 (en) * | 1987-03-24 | 1988-10-26 | BAJ Limited | Overlay coating |
| GB2226050A (en) * | 1988-12-16 | 1990-06-20 | United Technologies Corp | Thin abradable ceramic air seal |
| GB2226050B (en) * | 1988-12-16 | 1993-04-07 | United Technologies Corp | Thin abradable ceramic air seal |
| FR2651774A1 (en) * | 1989-09-08 | 1991-03-15 | United Technologies Corp | CERAMIC MATERIAL AND INSULATING COATING BASED ON THIS MATERIAL. |
| GB2243161B (en) * | 1990-04-17 | 1994-03-16 | Gen Electric | Coating systems for titanium oxidation protection |
| GB2243161A (en) * | 1990-04-17 | 1991-10-23 | Gen Electric | Coating systems for titanium oxidation protection |
| GB2252567A (en) * | 1991-02-11 | 1992-08-12 | Inst Elektroswarki Patona | Metal/ceramic protective coating for superalloy articles |
| GB2252567B (en) * | 1991-02-11 | 1994-09-14 | Inst Elektroswarki Patona | Metal/ceramic protective coating for superalloy articles |
| WO1996034128A1 (en) * | 1995-04-25 | 1996-10-31 | Siemens Aktiengesellschaft | Metal substrate with an oxide layer and an anchoring layer |
| EP0780484A1 (en) * | 1995-12-22 | 1997-06-25 | General Electric Company | Thermal barrier coated articles and method for coating |
| US5780110A (en) * | 1995-12-22 | 1998-07-14 | General Electric Company | Method for manufacturing thermal barrier coated articles |
| GB2317400A (en) * | 1996-09-19 | 1998-03-25 | Toshiba Kk | Thermal barrier coating providing reaction sintering suppression |
| GB2317400B (en) * | 1996-09-19 | 1999-02-24 | Toshiba Kk | Thermal barrier coating memner and method of producing the same |
| US5906895A (en) * | 1996-09-19 | 1999-05-25 | Kabushiki Kaisha Toshiba | Thermal barrier coating member and method of producing the same |
| WO2002092874A1 (en) * | 2001-05-15 | 2002-11-21 | Tohoku Techno Arch Co., Ltd. | Member coated with thermal barrier coating film and thermal spraying powder |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2159838B (en) | 1987-04-08 |
| BR8502550A (en) | 1986-02-04 |
| BE902581A (en) | 1985-09-30 |
| IL75304A (en) | 1989-03-31 |
| JPS613875A (en) | 1986-01-09 |
| FR2565525A1 (en) | 1985-12-13 |
| FR2565525B1 (en) | 1987-06-05 |
| SG54587G (en) | 1987-11-13 |
| GB8513942D0 (en) | 1985-07-03 |
| IL75304A0 (en) | 1985-09-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Effective date: 20050602 |