WO1994007004A1 - Aluminide-silicide coatings, coating compositions, process for coating and improved coated products - Google Patents
Aluminide-silicide coatings, coating compositions, process for coating and improved coated products Download PDFInfo
- Publication number
- WO1994007004A1 WO1994007004A1 PCT/US1993/008413 US9308413W WO9407004A1 WO 1994007004 A1 WO1994007004 A1 WO 1994007004A1 US 9308413 W US9308413 W US 9308413W WO 9407004 A1 WO9407004 A1 WO 9407004A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- coating
- aluminide
- silicide
- slurry
- zone
- Prior art date
Links
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
- 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
- C23C28/027—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 matrix material comprising a mixture of at least two metals or metal phases or metal matrix composites, e.g. metal matrix with embedded inorganic hard particles, CERMET, MMC.
-
- 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
- C23C10/18—Solid state diffusion of only metal elements or silicon into metallic material surfaces using liquids, e.g. salt baths, liquid suspensions
- C23C10/26—Solid state diffusion of only metal elements or silicon into metallic material surfaces using liquids, e.g. salt baths, liquid suspensions more than one element being diffused
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- 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
- 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
- C23C28/028—Including graded layers in composition or in physical properties, e.g. density, porosity, grain size
-
- 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
Definitions
- This invention relates to aluminide coatings for aluminizing of heat resistant alloy substrates, to the slurry coating compositions for the coatings and to a process for applying such coatings, more specifically to composite coatings containing aluminum-rich and silicon-rich phases to improve their resistance to hot corrosion and oxidation.
- MCrAlY overlay coatings also rely upon alumina films for their hot corrosion resistance. Owing to the presence of chromium and yttrium in the film, aluminum contents in these coatings do not need to be as high as in pack aluminides; however, protection is still derived from a tightly adherent scale of alumina.
- Slurry aluminizing is another alternative method of providing a protective, alumina forming intermetallic aluminide coating on a superalloy.
- an aluminum-filled slurry coating is first deposited on the hardware.
- aluminum in the film melts and reacts with the substrate to form the desired intermetallic phases.
- aluminide coatings to hot corrosion and oxidation is due to the thermodynamic stability of the alumina scale that forms on them. However, they do have some susceptibility to "low temperature" hot corrosion attack at about 700-800°C by alkali metal oxides (e.g. Na 2 0) and acidic oxides of refractory metals (e.g. Mo0 3 and W 2 0 3 ).
- alkali metal oxides e.g. Na 2 0
- acidic oxides of refractory metals e.g. Mo0 3 and W 2 0 3
- Silicon dioxide (Si0 2 ) is another very stable oxide. Like aluminum, silicon forms stable intermetallic compounds (suicides) with nickel and cobalt as well as chromium and other elements typically found in refractory alloys, such as molybdenum, tungsten and titanium. This reduces the segregation of these elements into the outer surface protective oxide layer, thus improving its protectiveness. Furthermore, unlike aluminum, silicon is unable to form sulphides and is resistant to sulphur diffusion. Consequently, suicide coatings, produced by pack or slurry processes, have been used on refractory alloys to improve resistance to hot corrosion and oxidation. Suicides have proven particularly useful in resisting sulphurous attack at "low" temperatures (700-800°C).
- silicon is classed as a metallic element for the purposes of this specification.
- Another means to produce so-called "silicon-modified” or “silicon-enriched” aluminides is to apply a slurry coating containing powdered aluminum and silicon metal to an alloy substrate containing aluminide and suicide forming elements and then heat it above 760°C (1500°F). As the aluminum and silicon in the slurry melt, they react with the substrate and diffuse preferentially. The aluminum alloys with nickel or cobalt in the substrate while silicon alloys with chromium or other suicide formers. The end result is a composite aluminide-silicide coating.
- This process is often termed a silicon modified slurry aluminide process and is commercially utilized under the trade name, "SermaLoy J", (a proprietary tradename of Sermatech International, Limerick, Pennsylvania, U.S.A. ) .
- Alloy substrates suited to this form of coating include nickel-based superalloys, cobalt-based superalloys and austenitic stainless steels. It is found that elements corresponding to the constituent elements of the alloy sub ⁇ strate are present throughout the extent of the coating but are combined differentially with the aluminum and silicon constituents of the coating such that the silicon rich phases are differently distributed through the thickness of the coating relative to the aluminum rich phases.
- the SermaLoy J slurry coating composition comprises silicon and aluminum elemental metallic powders in an acidic water solution of inorganic salts as a binder. About 15% by weight of the total metallic powder content of the slurry is silicon powder. However, the overall composition of the slurry in approximate weight percentages is
- Binder salts (dissolved in the water) - 12%
- a preferred mode of preparation of the composition is to premix the metallic powder constituents and make the binder solution separately, then mix the powder into the solution.
- Other ways of preparing the composition can readily be devised.
- This binder is selected to cure to a solid matrix which holds the metal pigments in contact with the metal surface during heating to the diffusion temperature. It also is selected to be fugitive during diffusion to yield residues that are only loosely adherent to the surface after diffusion has been completed.
- Diffusion heat treatment of an aluminum-silicon slurry coated superalloy or au ⁇ tenitic stainless steel substrate in an inert atmosphere or vacuum causes certain elements from the substrate and the slurry, which have a particular affinity for each other, to diffuse towards, and combine with each other.
- silicon in the coating has an affinity with the substrate metal chromium, and with molybdenum, tantalum and titanium, if present, and therefore, combines with one or more of these to form their suicides.
- silicon moves through the coating towards the substrate appreciably more slowly than the aluminum and therefore the outer parts of the coating become relatively enriched with silicon. Because chromium is present in superalloys and austenitic stainless steels in much larger amounts than the other elements for which silicon has an affinity, this silicon mostly combines with chromium during the diffusion treatment to produce an outer coating layer which is richer in chrome suicide than the rest of the coating.
- the coatings of the invention show a different composition of these layers and/or different thicknesses of the layers.
- An important object of the invention relates to a slurry aluminide coating which is particularly useful for superalloy substrates which in use, are frequently exposed to oxygen in gases at high temperatures.
- the coating has improved resistance to developing cracks during service while it maintains very satisfactory resistance to oxidation and hot corrosion conditions.
- a coating composition which comprises slurry of a powder of elemental metals typically aluminum and silicon and other metals further described below in a heat-curable binder, gives coatings with unexpected superior properties over coatings of the prior ' art, including SermaLoy J coatings.
- a coating which comprises a slurry of an eutectic aluminum-silicon powder in a heat-curable binder gives coatings with unexpected superior properties over the coatings of the prior art, including SermaLoy J coatings.
- aluminide- silicide coatings overall have a more even distribution of their constituents, particularly silicides throughout their thicknesses.
- Another aspect of the invention are coatings with reduced over-concentration of silicon content in the surface zone of such coatings, increased depth of the above-mentioned silicon- rich surface zone and of the layering zone, and increased dispersion of silicide phases within the aluminide zone.
- superalloy is a term well known in the art. When used herein, it refers to nickel-and cobalt-base alloys suitable as substrates for the coatings of the invention. However, austenitic stainless steels also form suitable substrates for at least some of the coatings of the invention and are considered superalloys for the purpose of the invention.
- Figure 1 shows what occurs when a typical substrate of an unprotected superalloy surface is exposed to clean combustion gases.
- Figure 2 shows what occurs when a typical substrate of an unprotected superalloy surface is exposed to combustion gases containing contaminants which contain chlorine and sulphur frequently found in marine environments under conditions of hot corrosion/sulphidation.
- Figure 3 shows a typical superalloy substrate which has been aluminized to form a diffused aluminide coating, with a highly adherent protective layer of alumina, Al 0 3 .
- Figure 4 shows a photomicrograph view at 500X magnifica ⁇ tion of a cross section through a normal SermaLoy J aluminide -silicide coating sample, the coating being on a nickel based superalloy substrate.
- Figures 5 to 13 are similar photomicrographs through other aluminide-silicide coating samples whose structure, composition or heat treatment have been modified in accordance with the present invention.
- Figures 14A and 14B are graphs showing the result of Electron Probe Micro Analysis (EPMA) for the distribution of various protective coating and superalloy substrate elements throughout the coating as shown in Figure 4, with elemental abundances in atomic percentages for Figure 14A and in weight percentages for Figure 14B plotted against a scale of microns through the sample.
- EPMA Electron Probe Micro Analysis
- Figures 15 to 22, 31A, and 31B show graphs of the results of EPMA for other selected coating samples, with elemental abundances in weight percentages plotted against a scale of microns through the samples.
- Figures 23 to 25 are graphs showing the result of accelerated hot corrosion testing of test pieces coated with various of the aluminide-silicide coatings which were investigated, with weight loss in milligrams plotted against time of test in hours;
- Figures 26 through 30 and 32 are photo micrographs of various coating samples.
- One embodiment relates to a coating composition which comprises a slurry containing several metals in elemental powder form (or state), in a liquid binder which is preferably heat-curable.
- An aspect of the embodiment is a powder which comprises the metal constituents, principally aluminum and silicon and other metals described hereinafter.
- the powder of the mixture of the metals is admixed with the binder which can be of a wide pH range, preferably an acidic binder.
- the invention also provides a method for applying the aqueous composition to a superalloy substrate and forming a coating highly resistant to oxidation and hot corrosion conditions with an improved resistance to developing cracks.
- the invention also provides improved coatings which under such demanding conditions have improved resistance to the formation of cracks, especially inception of cracks.
- the invention also provides improved work pieces coated with such coatings, for example, parts of gas turbine (industrial, marine and other) like rotor blades, turbine blades, casings and other parts.
- gas turbine industrial, marine and other
- the invention provides further novel embodiments.
- One embodiment relates to a slurry of eutectic aluminum- silicon powder in a heat-curable liquid binder.
- the slurry is especially useful to provide coatings for superalloy substrates which in use are frequently exposed to oxygen in gases at high temperatures and which normally tend to develop cracks.
- the slurry of the invention contributes to overcome these problems.
- the slurry optionally, may contain other metals in their elemental state, which contribute additional beneficial properties as described further hereinafter.
- the " invention in another embodiment, relates to the coatings formed on such superalloys from slurries containing such an eutectic aluminum silicon alloy.
- the coatings have increased dispersion of the alloys of silicon and the metals of the substrate throughout the coat's thickness. Further, the coatings of the invention have reduced silicon content and increased aluminum distribution in the outer zone of the coatings.
- the coatings of the invention have excellent properties; especially, they are remarkably resistant to the initiation or start of micro-cracks in the coating and have improved ductility.
- a signal aspect of the coatings of the invention is that the silicides are distributed or dispersed (or redistributed) more evenly throughout the thickness of the coatings than in the coatings of the prior art, typically SermaLoy J.
- the layering layer instead of being constituted of highly densely packed interleaved layers of aluminide and silicide phases, tends to be less densely (or closely) packed. Under optimum conditions, the silicide layers are more spaced apart, the aluminide layer tends to grow and the silicide particles distributed more evenly throughout that and the other layers of the coating.
- Another embodiment of the invention is coating wherein there is no surface layer, i.e., where the first outer layer is what is called the layering zone which comprises layers of silicide and aluminide phases.
- the invention further provides a method for preparing the eutectic ' slurry by bringing together and mixing elemental aluminum and silicon in eutectic proportions, then producing the eutectic alloy powder, then at the appropriate time when desired, mixing the eutectic powder with or without the optional other metal powder into the liquid binder solution.
- Another embodiment provides a process for coating a superalloy substrate with the slurry, curing the coatings, diffusion heating the coated substrate and cooling or allowing the coating to cure.
- Another embodiment relates to coated parts, generally metal parts having a superalloy component which is coated with the coating of the invention.
- Parts which benefit particularly from the coating of the invention are parts of gas turbines.
- the diffusion process may be applied as many times as deemed necessary in accordance with the process disclosed in above-referred to pending PCT International patent application PCT/US93/04507. Coating with further improved properties are obtainable.
- one important teaching of the invention relates to the distribution of the silicide and aluminide phases through the coating which distribution is different- from the distribution of the alloys in the coatings of the prior art.
- the silicides are more evenly distributed throughout the coating.
- a target aluminum concentration level at least within nickel aluminide coatings, but perhaps also within cobalt aluminide coatings, should be between about 20-30 wt.%, preferably about 25 to 30 wt.%.
- Nickel aluminide coatings with aluminum concentrations less than about 20 to 25 wt.% tend to have insufficient oxidation resistance, whereas coatings with aluminum concentrations in excess of about 30 wt.% are prone to cracking and premature failure. This is because a nickel aluminide coating with high aluminum concentrations tends to produce a multi-phase aluminide structure which adversely affects the mechanical properties of the coating.
- One aspect of the present invention provides a slurry coating composition for production of an aluminide-silicide coating.
- the slurry comprises metallic powder in elemental form in a binder liquid.
- the metal powder component of the slurry composition in weight percentage terms comprises the following constituents in the stated ranges:
- Ti, Ta and B which when present in the composition, are preferably present in the following amounts Ti - 0 to 10%, preferably 2 to 5%; Ta - 0 to 10%, preferably 2 to 5%, and boron in an amount of 0 to 2.5, preferably about 0.5 to 2%, most preferably from about 0.5 to 1%.
- Ti and Ta are preferably present together.
- the maximum aluminum content of 92.5% is sufficiently high so that a coating may be made with the stated minimum amounts of the other metallic elements.
- the minimum aluminum content of 30% is sufficiently high so that a coating may be made with the stated maximum amounts of the other metallic elements.
- Compositions with amounts of metals with depart from the upper and lower maximum stated tend not to give compositions with the desired properties.
- the lower the aluminum content of the slurry the more difficult it is to have the aluminum in the coating melt and diffuse readily.
- the present invention includes ranges of silicon content in the metal powder component of the slurry which are considerably greater than the 15 wt.% content found in SermaLoy J. It is an important aspect of the invention that as a result of the diffusion heat treatment of coatings formed from such Si-enriched slurries, the coating microstructure becomes richer in silicon, thereby making the silicon more immediately available for combination with chromium and other silicide formers present in the substrate and the coating before the surrounding material becomes relatively depleted of aluminum due to its rapid diffusion through the coating. In accordance with the invention, extra silicon to the slurry formulation also promotes thicker silicide rich surface zones.
- coatings of the invention made from slurries which contain Al in the slurry of metal powders in elemental form below the 85 wt% of Al in SermaLoy J, i.e., from about 65 to below about 85 wt%, distinguish over SermaLoy J by this smaller amount of Al and by the presence of the other metallic elements identified herein.
- coatings of the invention made from slurries which contain Si in the slurry of metal powder in elemental form below the 15 wt% of Si in SermaLoy J, i.e, from about 5 to below about 15 wt%, distinguish over SermaLoy J by this smaller amount of Si and by the presence of the other metallic elements identified herein.
- the coatings of the invention made from slurries which contain Al and Si in the lower ranges specified above distinguish therefore by virtue of these two reduced amounts and the presence of the other metallic components.
- Coatings of the invention made from slurries which contain Al and/or Si in excess of 85 wt% for Al and/or Si in excess of 15 wt%, distinguish over SermaLoy J because of the higher amounts of Al and/or Si, respectively. Likewise, it was unexpected that the slurries give such improved coatings.
- the chromium metal in the slurry coating composition of the invention is a silicide former, and therefore during the diffusion heat treatment it is attracted to the silicon.- Since it is already present throughout the coating at the commencement of diffusion, it binds to the neighboring silicon quickly, producing a more even distribution of silicide phases in the bulk of the coating, than is achievable in the SermaLoy J coating. Since there is no metal in the slurry for which the coating SermaLoy J is made, the latter relies for the production of chromium silicide therein on alloying with chromium present in the metallic substrate. Thus, in the coating of the invention, the chromium silicide is formed principally from the chromium of the coating composition as opposed to that from the substrate.
- chromium beneficially modifies the alumina/silica surface oxide scale produced on the coating during service. Like the aluminum and silicon already incorporated in known silicon modified aluminide coatings, chromium when oxidized forms a thin but non-porous surface scale which forms a barrier to further oxidation.
- Chromium has a further valuable oxide scale modifying chemical property in common with silicon, in that it forms an acidic oxide which gives good protection against high temperature sulphidation.
- Titanium and/or tantalum which can optionally be included in the slurry coating composition of the invention at the expense of the aluminum content, are strong silicide formers and in this respect supplement the effect given by incorporation of chromium in the slurry.
- titanium and/or tantalum in the slurry in amounts of about 2 to 3 wt.% of total metallic pigment content do not have such a pronounced effect on the production of silicides in the layering and aluminide zones of the finished coating as the addition of chromium to the slurry. Instead, they tend to become concentrated into the silicide rich surface zone. That surface zone, it has been found is broader than that in the SermaLoy J coating, besides being chemically different.
- Ti and Ta tend to modify the composition of the chromium silicide because both go into solid solution with chromium silicide to produce more complex silicides. They also have an affinity for - and form intermetallic compounds with - nickel, which is present in superalloy and other high-duty metallic substrates. Titanium aids the formation of the protective alumina scale at the coating surface by helping to liberate aluminum from the aluminide subsurface. Titanium is not a very protective oxide scale in itself, but may aid coherence- of the alumina scale. On the other hand, tantalum forms a dense stable oxide which is protective.
- Titanium and tantalum may be replaced singly or in combination by other chemically equivalent transition elements of Group 4b and 5b of the Periodic Table including, rhenium, zirconium and hafnium and manganese of Group 2a as part of the total metallic powder content of the slurry.
- the optional small amounts of boron which may be included in the slurry can be included at the expense of the aluminum content, in amounts up to 2.5 wt.%, preferably in the range 0.5 to 2 wt.%, most preferably in the range 0.5 to about 1 wt. %, of the total metallic powder content. Boron in small amounts reduces brittleness in the gamma prime nickel intermetallic compound Ni 3 Al which is present in the finished coating.
- the second important embodiment of the invention does not use aluminum and silicon in elemental form, but a eutectic aluminum-silicon alloy as further described hereinafter.
- This embodiment of the invention provides a slurry coating composition for production of an aluminide-silicide coating, the slurry comprising metallic powder in a binder liquid, the metallic powder component of the slurry comprising at least an aluminum-silicon alloy of eutectic composition.
- the eutectic composition of aluminum-silicon alloy in stoichiometric amount is 11.8 wt% Si, the balance 88.2 wt% being Al.
- the respective amounts of the two metals can depart from the specific values i.e., the stoichiometric amount, set forth above by about 7 to about 14 wt% without adversely affecting the metallic powder slurry. Indeed, the respective amounts of the two metals can even depart by a greater percentage. If carried to its logical and practical limits, it will be seen that the eutectic - or near eutectic alloy - will be replaced by substantially, essentially or completely, by Al and Si in elemental form.
- the eutectic Si- Al alloy powder can be used to partially or completely replace the elemental Si and Al powders normally used for SermaLoy J or in the composition of the invention described above which uses elemental Si and Al powders.
- the amount of Al-Si eutectic alloy in the slurry can vary from about 36 wt.% to 100 wt.% of the total metallic content, dependent upon the optional presence of additional metallic elemental powders. These may be present in the following weight percentage ranges:
- At least part of the Ta and/or the Ti constituents, if present, may be replaced by similar amounts of chemically similar transition elements, as described herein above.
- Chromium may be incorporated in this embodiment of the invention at the expense of the aluminum content for the same reasons as described above for coating compositions incorporating mixtures of elemental Al and Si powders.
- the resulting structure of the finished coating exhibits an advantageous combination of features, in particular, increased depth of the surface zone and/or increased depth of the layering zone, plus increased dispersion of the silicide phases, i.e., silicides through the aluminide zone.
- the optional metals used in conjunction with eutectic Al-Si alloy have additional advantages which they appear not to contribute so markedly to the slurry containing only elemental metal powders.
- the coating composition which comprises an eutectic Al-Si alloy will be described further herein below.
- a silicide-rich surface layer of at least 2 microns thick is of at least 2 microns thick.
- a layering layer which for optimum results is of a minimum thickness of 12 microns.
- a surface layer which has a maximum silicon content of less than about 25 wt%.
- a surface layer which includes at least one of Ta or Ti in amounts greater than the weight percentage content of the substrate material.
- a coating which also contains chromium and having a thicker surface layer and increased dispersion of silicide layers through the coatings.
- the binder used for the metallic components of the slurry in accordance with the invention is a liquid, preferably an aqueous liquid which is heat volatile, heat-curable and preferably leaves on the coating an inorganic residue that can be conveniently removed.
- binders are known. They can be an acidic neutral or basic liquid. They can be organic or inorganic, e.g., aqueous.
- the binder components of slurries including elemental and/or eutectic alloy powders of Si and Al may be an organic type (such as nitrocellulose or equivalent polymers) or one of the class of inorganic chromate, phosphate, molybdate or tungstate solutions described in U.S. Patents Nos. 4,537,632 (particularly columns 9 and 10), 4,606,967 and 4,863,516 (to Sermatech International, Inc.) which are incorporated herein by reference.
- the binder may also be one of the class of water-soluble basic silicates, which cure to tightly adherent glassy solids by loss of chemically bound water also disclosed therein.
- the coating goes through a curing phase.
- the metallic components of the binder are expelled from the coating. Any residue may be removed by brushing or similar suitable action.
- An aspect of the invention related closely to the compositional variations outlined above relates to the duration and temperature of the diffusion heat treatment to which a coated article is subjected.
- the diffusion heat treatment schedule for a SermaLoy J coated article is chosen to minimize both the effect of the diffusion heat treatment upon the mechanical properties of the substrate, and the effect that subsequent sustained high temperature operation, e.g., on the turbine blades in an engine, has on the microstructure of the coating.
- IN-738 nickel base superalloy material which has been coated with SermaLoy J slurry material and cured is normally diffusion heat treated at 870-885°C for about two hours.
- X-40 cobalt base superalloy coated in the same way is normally diffusion heat treated at about 870°C for about half an hour, before being heated to about 1000°C and held at the higher temperature for two hours.
- the following effects are noted for variations of temperature and time.
- the properties of the substrate material would be adversely affected by such high temperature diffusion, its use may be inadvisable unless it is feasible to restore the substrate material properties by a further heat treatment.
- a further heat treatment for instance by a precipitation heat treatment.
- IN-738 nickel based superalloy material coated with one of the above slurry mixtures and diffusion heat treated at 1200°C may have its properties restored by such treatment at 840°C for 24 hours.
- Example 1 The aluminum and silicon powders used in the slurries: in some slurries, instead of the Al and Si powders being in elemental form, as for normal SermaLoy J, Al/Si alloy powder of eutectic composition was used. This reduced the freedom of Al and Si to diffuse through the coating independently of each other, thereby reducing Si concentration in the surface zone.
- Example 2 Addition of certain metallic elements to the slurry which are strong silicide formers: these were (in weight percent relative to the total metallic pigment content of the coating), Cr 5% or 10%, Ti 2.5%, Ta 2.5%. This controlled the movement of silicon during diffusion heat treatment and resulted in good silicide formation throughout the coating.
- Example 3 Alteration of amount of Al in the slurry: Al content relative to the total metallic pigment content of the coating was varied in the range 65 to 95 wt.%.
- Example 5 Addition of 1 wt.% boron to the slurry. This rendered the aluminide phases more ductile.
- Example 6 Changes to diffusion heat treatment temperatures. Different temperatures tried: 760°C, 870°C, 885°C and 1120°C. Reduction of temperature below the normal SermaLoy J diffusion temperatures of 870°C to 885°C reduced the rate of diffusion of Al, thereby increasing Al concentration in the surface zone of the coating. Increasing diffusion temperature above the normal for SermaLoy J increased the diffusion rate of the heavier substrate material elements without greatly increasing the Al diffusion rate, thereby lowering both Al and Si concentration in the surface zone.
- Example 7 Changes to diffusion heat treatment times. Different times were tried: 2, 3.5, 4, 5, 6.5, and 8 hours. The increase of diffusion time above the diffusion time of 2 hours customarily applied to SermaLoy J caused the diffusion of the coating to be complete.
- Slurry A corresponds to Slurry Sample Number 1A1 in Table 1 and is a normal slurry composition for SermaLoy J, having a solids content of approximately 60 wt.%. It gives a coating in which aluminum provides 85 wt.% of the total metal powder content and silicon provides 15 wt.%.
- the second, third and fourth ingredients combine to form a magnesium salt of chromic and phosphoric acid, this being the binder for the metallic constituents to enable curing of the coating, but which is later expelled from the coating upon diffusion heat treatment.
- Slurry B has sufficient chromium powder added to make a coating in which 10 wt.% of the total metal powder content is chromium. It corresponds to Slurry Sample Number 1B3 in Table 1.
- the samples Prior to application of the slurry, the samples were degreased in hot vapor of 1,1,1-trichloroethane, then blasted with 90/120 mesh alumina grit to prepare the surfaces for coating. Grit blasting was done in a pressure cabinet at a pressure of 20 psi or 138kPa.
- a thin wet coat of each slurry was applied to the blasted samples using a conventional air atomizing spray gun. After allowing the water to evaporate, the sprayed slurry coat was dried at 80°C (175°F) for at least 15 minutes, then cured for 30 minutes at 350°C (660°F).
- Curing temperatures for conventional coatings are suitable. It is possible to cure at higher temperatures, for instance to about 600°C, to accelerate the curing process, provided the temperature chosen is adequately below the melting point of aluminum. It would also be possible to cure at lower temperatures, consistent with achieving curing within a reasonable time.
- the coating thickness was built up by applying and curing further slurry coats following the procedure outlined above.
- the weight (thickness) of coating applied in this way to the samples was standardized at a total of about 18-27 mg/cm 2 of cured slurry.
- the lower end of the range is more suited to conventional SermaLoy J coatings, while the upper end of the range is more suited to the heavier weight coatings of the invention which incorporate the heavy metal chromium as a significant constituent.
- Each one of the coated samples was then subjected to one of the specified diffusion heat treatment schedules.
- this involved the normal SermaLoy J heat treatment comprising heating to 870°C (1600°F) or 885°C (1625°F) and holding at that temperature for two hours to inter-diffuse the coating constituents and the base material.
- SermaLoy J heat treatment comprising heating to 870°C (1600°F) or 885°C (1625°F) and holding at that temperature for two hours to inter-diffuse the coating constituents and the base material.
- Table 1 above shows various samples, their constitution and heat treatment thereof.
- Typical photomicrographs of the coating sections seen in these samples are shown in Figures 4 to 13, 26 to 30 and 32 and examples of EPMA are shown in Figures 14 to 22 and 31, corresponding to the microstructure Figures 14 to 22.
- the origins of the EPMA graphs i.e. the baselines for the beginning of each scan by the electron probe) were just beyond the outer surface of the coating.
- Sample mounting compound e.g., "Bakelite” - trade mark
- Silicon-rich surface zone where chromium silicide and other silicides are particularly concentrated. This zone is patchy or absent in some samples.
- Layering zone comprising alternate interleaved layers of silicide and aluminide phases - this zone is not always distinguished clearly from other zones.
- Aluminide zone predominantly comprising aluminide phases, but with greater or lesser amounts of silicide precipitates.
- X. Precipitate zone In samples diffused at high temperatures, an aluminide zone with pronounced silicide precipitates of refractory metals, but with lower aluminum concentration than in samples diffused at normal diffusion temperatures.
- Y. Nickel-rich zone In samples diffused at high temperatures, an aluminide zone with high nickel content.
- F. Interface diffusion zone At the interface between the coating and the substrate material, where the grain structure has been visibly altered by the diffusion process.
- Figure 4 shows a conventional SermaLoy J coating microstructure as produced on an IN-738 substrate and subjected to the normal diffusion heat treatment process as specified above.
- the coating is about 50 ⁇ m thick in total and exhibits the above zones C, D, E, and F.
- the silicon-rich surface zone C is only about 5 ⁇ m thick.
- Layering zone D where aluminide phases and silicide phases are interleaved with each other, is about 15 ⁇ m thick, but the layers are somewhat discontinuous.
- Aluminide zone E exhibits silicide precipitates.
- Interface diffusion zone F is about 5 ⁇ m thick. The latter zone is not counted as part of the thickness of the coating for present purposes, since it partakes of the character of both the coating and the substrate material G. Zones X and Y are not present, since this sample was diffused at only 870°C.
- the sample was subjected to EPMA with the result shown in Figures 14A and 14B, confirming that the coating is a composite of nickel aluminide and silicides, primarily chromium silicides.
- the affinities of Al for Ni and Si for Cr are the dominant features.
- the measured concentration of silicon in the surface zone is as high as 38 atomic % (34 wt.%) silicon at locations within the first 10 microns of the coating surface. Cracks were found in the sample of Figure 4 when it was subject to visual and X-ray mapping inspection.
- Nickel aluminides with higher aluminum concentration tend to produce multi-phase structures which adversely affect the mechanical properties of the coating. It is recognized that a target aluminum level within the coating should be between 25- 30 wt.%, whereas Figure 14 shows Al levels consistently well above 40 atomic %, 28.6 wt.%, peaking to over 50 atomic %, 35.7 wt.%.
- Figures 10 to 13 show samples in which metallic content of the coating as applied and cured comprised elemental powders modified by the addition of various amounts of chromium from about 3 to 13 wt.%. Diffusion heat treatment was at 885°C for two hours.
- zone C in the samples tends to be reduced in thickness, while zone D tends to increase in thickness.
- Sample 9E, Figure 13 has only 3.3 wt.% Cr and an increased silicon content compared to sample J, resulting in a more pronounced silicon-rich surface zone C, but a thinner layering zone E.
- Figure 5 shows coating sample 1A6, in which metallic content of the coating as applied and cured comprised elemental powders modified by the addition of 10 wt,% silicon and 5 wt.% chromium at the expense of the aluminum content. Diffusion heat treatment was the same as normally used for SermaLoy J. The surface layer zone C is now appreciably thicker than in sample J, with zone D quite thin and not very pronounced. However, the coating is 40% thicker than sample J, and referring to the EPMA result in Figure 18, it should be noted that the wt.% levels of Si, Al, Cr and Ni throughout the coating depth are much more constant than for sample J.
- Al content is about 20 to 24 wt.% throughout and the maximum measured silicon concentration in the top zone of the coating is 10 wt.%.
- the conclusion to be drawn is that addition of Cr has helped to disperse Si through the coating, but the additional Si has also helped to form the thicker zone C.
- SermaLoy J coating concentrations of Ta and Ti in the silicon-rich surface zone C are about 1 wt.% and 4 wt.% respectively, see Figure 14A.
- sample 1A2, Figure 15B, and sample 1A5, Figure 17B show Ta concentrations up to about 3%
- samples 1A4 and 1A7 show Ti concentrations up to about 5% and 10% respectively.
- the EPMA's plotted here show that the added amounts of Ta and Ti were incorporated in the finished coating, but instead of forming silicides within the body of the coating, Ta and Ti became concentrated in zone C, at least when used in conjunction with elemental Al and Si powders.
- tantalum without titanium increased the propensity of the coatings to crack, probably due to the mis ⁇ match in atomic size between Ta and Si causing strain in the microstructure of the surface zone where Ta had concentrated.
- the silicide rich zones became wider than those of normal SermaLoy J, tending to be less prone to crack initiation.
- zone C by Ta and Ti relate to their ability to form silicides, to go into solid solution with chromium silicide to produce complex silicides, and their affinity for nickel from the substrate to form intermetallic compounds such as Ni 3 Ti.
- both aid formation of protective alumina scale at the surface of the coating during service, since they help to liberate Al from the aluminide phase.
- Ti0 2 is not very protective by itself, it may aid coherence of the alumina scale. Tantalum also forms a dense stable oxide in use which is protective.
- Figure 6 is a scanning electron micrograph of coating sample 1A9, in which metallic content of the coating as applied and cured consisted entirely of powdered aluminum- silicon alloy of eutectic composition. Diffusion heat treatment was the same as normally used for SermaLoy J. Figure 6 should be viewed in conjunction with Figure 20, which shows the result of the corresponding EPMA.
- Zone F is flat and fine grained, as in Figure 4, leading to good mechanical properties at the interface.
- zone C in Figure 6 is very thin and patchy, and has not been counted as part of the total thickness of the coating, but zone D comprises approximately the outer 40% of the coating thickness, about 35 ⁇ m. Furthermore, the layering in zone D is not so discontinuous as for the same zone in Figure 4.
- Zone E in Figure 6 is about 20 ⁇ m thicker than the same zone in Figure 4, but takes up about the same proportion of the total coating thickness.
- Sample 9U (see Figure 7A) was diffused at a slightly higher temperature than samples J and 1A9, though still normal for SermaLoy J coating production. It incorporated about 69 wt.% of eutectic Al-Si powder, with elemental additions of aluminum and silicon and about 3 wt.% chromium.
- Total coating thickness is only 20% greater than in Figure 4, with zone C being somewhat more pronounced than in Figure 6, but patchier than Figure 4. Though zone D for sample 9U is still thicker than for sample J, the difference is not pronounced. It is evident that some of the silicide content which had been spread as layers through zone D in Figure 6 [coating 1A9] has segregated to the surface zone C in Figures 7A [coating 9U, eutectic + Cr powder].
- Adding Ti and Ta powder to the eutectic Al/Si alloy powder and chromium powder in slurry 1A15 produced an aluminide with a more homogeneous microstructure than either of the eutectic alloy, slurries that did not contain those constituents. None of the layering of silicon-rich phases seen in coating 1A9 (zone D in Figure 6) is visible in the outer zone of the 1A15 aluminide ( Figure 7B). These silicides instead are uniformly distributed within the nickel aluminide in that zone. Though microprobe analysis in Figures 21A and B showed there was a similar amount of silicon in 1A15 (up to about 6%) as in the other coatings.
- Figure 21A shows that this silicon was quite evenly spread through the outer zone. This is unlike the structure of coating 1A9, Figure 20. In that coating, formed by diffusion of eutectic Al/Si alloy without additions of Cr, Ti or Ta, silicon concentrations in the outer layers were more variable.
- the silicon-aluminum slurries must be diffused above about 854°C, preferably at 870°-885°C, to form an aluminum-rich NiAl phase without formation of the brittle stoichiometric NiAl 3 phase.
- This critical temperature was confirmed in this study when the diffusion temperature was lowered to 760°C in an effort to reduce the rate of diffusion of Al and consequently increase Al concentration (i.e., reduce Si concentration) in the outer zone of these coatings. In that case, thinner coatings were produced and their Al levels were too high.
- Diffusing at 870°C to 885°C enables what can be termed a high activity aluminizing process, in which aluminum inward diffusion is the main reaction.
- Sample 1B9 in Figure 8 shows the result of high temperature diffusion of a slurry whose metallic powder content is 100 wt.% eutectic Al-Si alloy. Most notable is the greatly increased total thickness of the coating, 130% greater than sample J, resulting from the previously noted thickening effect of the eutectic alloy added to the increased diffusion temperature. Unlike sample 1A9 comprising eutectic alloy powder, but diffused at lower temperature, a pronounced 5 ⁇ m- thick Si-rich surface zone C is apparent, probably due to greater inward diffusion of aluminum. However, a thick layering zone has been formed, as in 1A9, and good precipitate formation throughout the underlying zones is likewise evident.
- Figures 9 and 22 also show features resulting from the combination of two different coating modifying changes, namely, use of an amount of additional strong silicide former in the slurry mix (+10 wt.% Cr) and increased diffusion temperature, i.e. 1120°C.
- the microstructure shows a patchy zone C and a thicker layering zone D, despite the fact that the overall thickness of the coating is somewhat less than for sample 1B9 in Figure 8.
- Cr appears to have been effective at encouraging silicide formation within zones D,X, and Y at the expense of zone C.
- the high diffusion temperature has modified zone F relative to sample J.
- These refractory elements are strong carbide formers, and consequently their movement through the coating is arrested by the carbide formation at the interface. This is advantageous because their oxides tend to be deleterious to the protective properties of the coating's surface scale which is formed in service, so they should be kept away from the surface if possible.
- Increased diffusion heat treatment time also produced somewhat thicker coatings, but the effect was not so pronounced as it was for increased temperature.
- the samples Prior to application of coating slurry, the samples were degreased in hot vapor of 1,1,1 trichloroethane, then blasted with 90/120 mesh alumina grit at 20 psi or 138kPa.
- a thin wet coat of each slurry was applied to the blasted samples using a conventional air atomizing spray gun. After allowing the water to evaporate, the sprayed slurry coat was dried at 80°C (175°F) for at least 15 minutes, then cured for 30 minutes at 350°C (660°F).
- the coating thickness was built up by applying and curing further slurry coats following the procedure previously outlined in respect of the disc samples.
- each of the coated samples was then subjected to a diffusion heat treatment schedule involving diffusion at 885°C for 2 hours.
- a diffusion heat treatment schedule involving diffusion at 885°C for 2 hours.
- undiffused residues were removed by lightly blasting with -140 +220 glass beads at 20 psi (138kPa) in a suction blaster.
- pins were heated for three minutes in an open flame fuelled by propane, achieving a steady state temperature of 950°C(1740°F) within about 60 seconds. Then the hot pins were quenched to room temperature within 60 seconds in a fine atomized spray of an aqueous solution containing 1 wt.% Na 2 S0 4 and 10 wt.% NaCl. After three minutes in the spray, the complete heating and quenching cycle was repeated and this was continued for a total of about 140 hours. About every seven or eight hours the test was interrupted and the pins were removed, ultrasonically cleaned in de-ionized water, weighed and examined by eye. Any pins exhibiting distress were removed and substituted with bare pins to keep the mass identical at all times.
- Figures 23 (15 pins), 24 (12 pins) and 25(15 pins), which are graphs showing weight loss in milligrams, plotted against time of test in hours.
- the solid lines labelled as relating to the different types of coating sample are only an indication of the average loss of weight for each pin and therefore disguise individual pin results, which will be discussed below.
- Graph lines for pins coated in normal SermaLoy J are labelled "J".
- the other notable coating sample in Figure 23 is number 1A6, again comprising three pins, which outlasted the SermaLoy J coated pins.
- this coating sample described above in relation to Figures 5 and 18, comprised elemental Si and Al powders, with 5 wt.% Cr and 10 wt.% Si added at the expense of the usual Al content for normal SermaLoy J.
- the better performance is probably due to the presence of a thick silicide-rich surface layer C resulting from the extra silicon and the addition of chromium as a strong silicide former.
- Samples 1B3 and 1B9 which had been subjected to the high temperature diffusion heat treatment (see Table 1), did not give optimum performance.
- the decrease in hot corrosion resistance is believed to be due to depletion of the coatings' aluminum content by its migration into the substrate material during the high temperature treatment.
- the thicker, more ductile coating and the better dispersion of the silicides therein typified by these samples may be attractive enough advantages of the high temperature treatment, especially when combined with addition of silicide formers to the slurry.
- coating sample 9E it is important to notice that though in the earlier stages of the test the pins seemed to perform less well than the others, their performance was more consistent and at the end of the test they had not suffered the rapid loss of remaining coating characterizing the SermaLoy J coating samples. There was still some coating thickness available in all the 9E pins at the end of the test.
- Coating 1U served as a kind of negative standard to test the presuppositions of the test strategy.
- the slurry contained, as a proportion of metal pigment content, 20 wt.% chromium, with Si and Al contents of only 5 wt.% and 75 wt.% respectively, part of the aluminum and silicon content being elemental powders, and part being eutectic alloy powder.
- the aluminide produced by this slurry seemed to be quite ductile but lacked any of the microstructural features thought necessary for good resistance to hot corrosion. Pins coated with this composition failed quickly. See Figure 25.
- Coating 2U contained no chromium, with Si and Al contents of 25 wt.% and 75 wt.% respectively. As before, part of the aluminum and silicon content was in the form of elemental powders, and part was eutectic alloy powder.
- Coating 6U also contained no chromium, but Si and Al contents were 15 wt.% and 85 wt.% respectively. Therefore, with respect to total Al and Si content, it was like a standard SermaLoy J slurry, but again, part of the aluminum and silicon content was in the form of elemental powders, and part was eutectic alloy powder.
- the final overall ranking of the best coating samples for weight loss during the hot corrosion tests was as follows, starting with least weight loss: 9E, J, 9U, 4E and 7E.
- a pin coated with coating sample 9E gives coating of improved performance.
- a coating of sample 9U is applied to a rotor blade of a gas turbine engine, a comparable improved coating resulted.
- a coating on an airfoil with sample 1A6 gives a coating with a thick surface layer of reduced silicon content and improved performance.
- a fastener coated with coating sample 9U gives a coating of improved performance.
- the coatings of the invention are not limited to gas turbines but include coating any superalloy coated part exposed to the operating conditions to which it is normally exposed in use like reciprocating engines, space vehicles (aerodynamically, like heated skins), steam power engines and the like.
- Hot corrosion resistance with resistance to the inception of crack formation in the coating on superalloys is a serious problem facing the industry.
- the problem becomes increasing serious as conditions of use become more demanding.
- the present invention makes a contribution to solving this problem in this field.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Composite Materials (AREA)
- Inorganic Chemistry (AREA)
- General Engineering & Computer Science (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
- Powder Metallurgy (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP93923717A EP0619856B1 (en) | 1992-09-05 | 1993-09-07 | Aluminide-silicide coatings, coating compositions, process for coating and improved coated products |
US08/240,691 US5795659A (en) | 1992-09-05 | 1993-09-07 | Aluminide-silicide coatings coated products |
JP50758994A JP3614430B2 (en) | 1992-09-05 | 1993-09-07 | Aluminide / silicide coatings, coating compositions, coating methods and improved coating products |
CA002123135A CA2123135C (en) | 1992-09-05 | 1993-09-07 | Aluminide - silicide coatings, coating compositions, process for coating and improved coated products |
DE69326938T DE69326938T2 (en) | 1992-09-05 | 1993-09-07 | ALUMINUM SILICIDE COATINGS, SURFACE COATING COMPOSITIONS, COATING METHODS AND IMPROVED COATED PRODUCTS |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB929218859A GB9218859D0 (en) | 1992-09-05 | 1992-09-05 | Aluminide-silicide coatings |
GB9218859.8 | 1992-09-05 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO1994007004A1 true WO1994007004A1 (en) | 1994-03-31 |
WO1994007004B1 WO1994007004B1 (en) | 1994-04-14 |
Family
ID=10721489
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1993/008413 WO1994007004A1 (en) | 1992-09-05 | 1993-09-07 | Aluminide-silicide coatings, coating compositions, process for coating and improved coated products |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0619856B1 (en) |
JP (1) | JP3614430B2 (en) |
CA (1) | CA2123135C (en) |
DE (1) | DE69326938T2 (en) |
GB (1) | GB9218859D0 (en) |
WO (1) | WO1994007004A1 (en) |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999042633A1 (en) * | 1998-02-23 | 1999-08-26 | MTU MOTOREN- UND TURBINEN-UNION MüNCHEN GMBH | Method for producing a slip layer which is resistant to corrosion and oxidation |
WO2000070190A1 (en) * | 1999-05-14 | 2000-11-23 | Siemens Aktiengesellschaft | Component and method for producing a protective coating on a component |
EP1681374A1 (en) * | 2005-01-14 | 2006-07-19 | Siemens Aktiengesellschaft | Coating system with barrier layer and process of manufacture |
EP1820875A2 (en) * | 2006-02-21 | 2007-08-22 | General Electric Company | Corrosion coating for turbine blade environmental protection |
EP2270313A3 (en) * | 2009-06-30 | 2015-07-22 | Mitsubishi Hitachi Power Systems, Ltd. | High-temperature resistant gas turbine component |
RU2564646C1 (en) * | 2014-04-04 | 2015-10-10 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Дальневосточный государственный университет путей сообщения" (ДВГУПС) | Diffusion spraying of protective coating from alloy of zirconium and silicon on surface of steel parts |
EP3015568A1 (en) * | 2014-10-29 | 2016-05-04 | MTU Aero Engines GmbH | Dross and method for producing an oxidation and corrosion resistant diffusion layer |
RU2685905C1 (en) * | 2017-12-05 | 2019-04-23 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Московский авиационный институт (национальный исследовательский университет)" | Material for heat-resistant protective coating |
CN113774319A (en) * | 2021-08-11 | 2021-12-10 | 湖南兴弘新材料科技有限公司 | Chromium-free aluminized silicon composition, slurry, preparation method and application thereof |
CN114790537A (en) * | 2022-04-27 | 2022-07-26 | 宁波金鼎紧固件有限公司 | High-performance engineering fastener material and production method thereof |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6089825A (en) * | 1998-12-18 | 2000-07-18 | United Technologies Corporation | Abradable seal having improved properties and method of producing seal |
US6511630B1 (en) * | 1999-10-04 | 2003-01-28 | General Electric Company | Method for forming a coating by use of foam technique |
EP3141631B1 (en) | 2015-09-10 | 2018-03-14 | Rolls-Royce High Temperature Composites Inc | Applying silicon metal-containing bond layer to ceramic or ceramic matrix composite substrates |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
USRE26001E (en) * | 1966-04-26 | Diffusion coating of metals | ||
US3325279A (en) * | 1965-12-03 | 1967-06-13 | Dow Chemical Co | Aluminum-high silicon alloys |
US3544348A (en) * | 1968-10-25 | 1970-12-01 | United Aircraft Corp | Overhaul process for aluminide coated gas turbine engine components |
US4374183A (en) * | 1980-06-20 | 1983-02-15 | The United States Of America As Represented By The Administrator, National Aeronautics And Space Administration | Silicon-slurry/aluminide coating |
US4500364A (en) * | 1982-04-23 | 1985-02-19 | Exxon Research & Engineering Co. | Method of forming a protective aluminum-silicon coating composition for metal substrates |
US4902475A (en) * | 1987-09-30 | 1990-02-20 | Metallurgical Products & Technologies, Inc. | Aluminum alloy and master aluminum alloy for forming said improved alloy |
US5120613A (en) * | 1989-01-26 | 1992-06-09 | Asea Brown Boveri Ltd. | Pocess for increasing the resistance to corrosion and erosion of a vane of a rotating heat engine |
-
1992
- 1992-09-05 GB GB929218859A patent/GB9218859D0/en active Pending
-
1993
- 1993-09-07 WO PCT/US1993/008413 patent/WO1994007004A1/en active IP Right Grant
- 1993-09-07 JP JP50758994A patent/JP3614430B2/en not_active Expired - Lifetime
- 1993-09-07 DE DE69326938T patent/DE69326938T2/en not_active Expired - Lifetime
- 1993-09-07 CA CA002123135A patent/CA2123135C/en not_active Expired - Lifetime
- 1993-09-07 EP EP93923717A patent/EP0619856B1/en not_active Expired - Lifetime
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
USRE26001E (en) * | 1966-04-26 | Diffusion coating of metals | ||
US3325279A (en) * | 1965-12-03 | 1967-06-13 | Dow Chemical Co | Aluminum-high silicon alloys |
US3544348A (en) * | 1968-10-25 | 1970-12-01 | United Aircraft Corp | Overhaul process for aluminide coated gas turbine engine components |
US4374183A (en) * | 1980-06-20 | 1983-02-15 | The United States Of America As Represented By The Administrator, National Aeronautics And Space Administration | Silicon-slurry/aluminide coating |
US4500364A (en) * | 1982-04-23 | 1985-02-19 | Exxon Research & Engineering Co. | Method of forming a protective aluminum-silicon coating composition for metal substrates |
US4902475A (en) * | 1987-09-30 | 1990-02-20 | Metallurgical Products & Technologies, Inc. | Aluminum alloy and master aluminum alloy for forming said improved alloy |
US5120613A (en) * | 1989-01-26 | 1992-06-09 | Asea Brown Boveri Ltd. | Pocess for increasing the resistance to corrosion and erosion of a vane of a rotating heat engine |
Non-Patent Citations (1)
Title |
---|
METALS HANDBOOK, "Aluminum Coating of Steel", AMERICAN SOCIETY FOR METALS, METALS PARK, OHIO, 1964, pp. 489-497. * |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999042633A1 (en) * | 1998-02-23 | 1999-08-26 | MTU MOTOREN- UND TURBINEN-UNION MüNCHEN GMBH | Method for producing a slip layer which is resistant to corrosion and oxidation |
US6440499B1 (en) * | 1998-02-23 | 2002-08-27 | Mtu Aero Engines Gmbh | Method for producing a slip layer which is resistant to corrosion and oxidation |
WO2000070190A1 (en) * | 1999-05-14 | 2000-11-23 | Siemens Aktiengesellschaft | Component and method for producing a protective coating on a component |
US6755613B1 (en) | 1999-05-14 | 2004-06-29 | Siemens Aktiengesellschaft | Component and method for producing a protective coating on a component |
EP1681374A1 (en) * | 2005-01-14 | 2006-07-19 | Siemens Aktiengesellschaft | Coating system with barrier layer and process of manufacture |
EP1820875A2 (en) * | 2006-02-21 | 2007-08-22 | General Electric Company | Corrosion coating for turbine blade environmental protection |
EP1820875A3 (en) * | 2006-02-21 | 2008-04-23 | General Electric Company | Corrosion coating for turbine blade environmental protection |
EP2270313A3 (en) * | 2009-06-30 | 2015-07-22 | Mitsubishi Hitachi Power Systems, Ltd. | High-temperature resistant gas turbine component |
RU2564646C1 (en) * | 2014-04-04 | 2015-10-10 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Дальневосточный государственный университет путей сообщения" (ДВГУПС) | Diffusion spraying of protective coating from alloy of zirconium and silicon on surface of steel parts |
EP3015568A1 (en) * | 2014-10-29 | 2016-05-04 | MTU Aero Engines GmbH | Dross and method for producing an oxidation and corrosion resistant diffusion layer |
EP3483303A1 (en) | 2014-10-29 | 2019-05-15 | MTU Aero Engines GmbH | Dip coat and method for producing an oxidation and corrosion resistant diffusion layer |
US10316198B2 (en) | 2014-10-29 | 2019-06-11 | MTU Aero Engines AG | Slip and process for producing an oxidation- and corrosion-resistant diffusion layer |
RU2685905C1 (en) * | 2017-12-05 | 2019-04-23 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Московский авиационный институт (национальный исследовательский университет)" | Material for heat-resistant protective coating |
CN113774319A (en) * | 2021-08-11 | 2021-12-10 | 湖南兴弘新材料科技有限公司 | Chromium-free aluminized silicon composition, slurry, preparation method and application thereof |
CN114790537A (en) * | 2022-04-27 | 2022-07-26 | 宁波金鼎紧固件有限公司 | High-performance engineering fastener material and production method thereof |
CN114790537B (en) * | 2022-04-27 | 2023-09-15 | 宁波金鼎紧固件有限公司 | Engineering fastener material and production method thereof |
Also Published As
Publication number | Publication date |
---|---|
EP0619856B1 (en) | 1999-11-03 |
JP3614430B2 (en) | 2005-01-26 |
DE69326938D1 (en) | 1999-12-09 |
JPH08501351A (en) | 1996-02-13 |
EP0619856A4 (en) | 1995-01-18 |
EP0619856A1 (en) | 1994-10-19 |
CA2123135C (en) | 2005-11-29 |
CA2123135A1 (en) | 1994-03-31 |
GB9218859D0 (en) | 1992-10-21 |
DE69326938T2 (en) | 2000-02-17 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5795659A (en) | Aluminide-silicide coatings coated products | |
US5650235A (en) | Platinum enriched, silicon-modified corrosion resistant aluminide coating | |
EP0596099B1 (en) | Multiplex aluminide-silicide coating | |
CA1069779A (en) | Coated superalloy article | |
US4933239A (en) | Aluminide coating for superalloys | |
CA1055326A (en) | Platinum-rhodium-containing high temperature alloy coating | |
US4339509A (en) | Superalloy coating composition with oxidation and/or sulfidation resistance | |
US4326011A (en) | Hot corrosion resistant coatings | |
EP0587341B1 (en) | High temperature corrosion resistant composite coatings | |
JP4383499B2 (en) | Oxidation-resistant alloy film, method for producing oxidation-resistant alloy film, and heat-resistant metal member | |
US6921586B2 (en) | Ni-Base superalloy having a coating system containing a diffusion barrier layer | |
EP0619856B1 (en) | Aluminide-silicide coatings, coating compositions, process for coating and improved coated products | |
US4371570A (en) | Hot corrosion resistant coatings | |
EP2432912B1 (en) | Forming reactive element modified aluminide coatings with low reactive element content using vapor phase diffusion techniques | |
EP0131536B1 (en) | Chromium boron surfaced nickel-iron base alloys | |
JPH0266181A (en) | Corrosion-resistant coating for oxide dispersed reinforced alloy | |
GB2056487A (en) | Superalloy coating composition | |
Mutasim et al. | Effects of alloy composition on the performance of diffusion aluminide coatings | |
JP2930497B2 (en) | Method of forming high temperature corrosion resistant alloy spray coating | |
Dust et al. | Hot corrosion resistance of chromium modified platinum-aluminide coating | |
El-Zomor et al. | Effect Of Zirconia Addition On Microstructure And Surface Properties Of Chromoaluminized Steel |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): CA DE GB JP US |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1993923717 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2123135 Country of ref document: CA |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) |
Free format text: CA,DE,GB,US, EUROPEAN PATENT(AT,BE,DE,DK,FR,GB,IE,IT,LU,MC,NL,PT,SE) |
|
WWP | Wipo information: published in national office |
Ref document number: 1993923717 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 08240691 Country of ref document: US |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
WWG | Wipo information: grant in national office |
Ref document number: 1993923717 Country of ref document: EP |