• 专利附录
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    • 专利摘要:
    PURPOSE: Bond coatings which provide very good adhesion between the substrate and a subsequently-applied TBC, e.g., bond coatings with a relatively rough surface are provided, and new processes for applying and curing such coatings in regions of a substrate which are somewhat inaccessible are provided. CONSTITUTION: The method for applying a bond coat on a metal-based substrate, comprising the following steps of a) applying a slurry which comprises braze material to the substrate, wherein the slurry also contains a volatile component; b) applying bond coat material to the substrate; c) drying the slurry and bond coat material to remove at least a portion of the volatile component; and d) fusing the braze material and bond coat material to the substrate. The method for applying a metal aluminide- or MCrAlY-based bond coat on a superalloy substrate, where M is nickel, cobalt, or a mixture thereof, comprises the following steps of (I) applying a slurry which comprises a volatile component and a mixture of braze material and bond coat material to the substrate, wherein the braze material contains at least about 40% by weight nickel; (II) drying the slurry under conditions sufficient to remove at least a portion of the volatile component, forming a green coating; and (III) brazing the green coating to the substrate. The method for replacing a bond coat applied over a metal-based substrate comprises the following steps of (i) removing the existing bond coat from a selected area on the substrate; (ii) applying a slurry which comprises braze material to the selected area, wherein the slurry also contains a volatile component; (iii) applying additional bond coat material to the selected area; and (iv) fusing the braze material and bond coat material to the selected area. The slurry composition comprises a soldering material and a bond coating material. The article comprises (a) a metal-based substrate; and (b) a volatile-containing slurry on the substrate, comprising braze material and bond coat material. The article comprises (i) a metal-based substrate, and (ii) a brazed bond coat comprising bond coat particles, disposed over the substrate, wherein the braze material forms a continuous matrix phase in which the bond coat particles are embedded.
    公开号:KR20020006478A
    申请号:KR1020010041673
    申请日:2001-07-11
    公开日:2002-01-19
    发明作者:하즈웨인챨스；산기타디(엔엠엔)
    申请人:제이 엘. 차스킨, 버나드 스나이더, 아더엠. 킹；제너럴 일렉트릭 캄파니；
    IPC主号:
    专利说明:

    TECHNICAL FIELD [0001] A METHOD FOR APPLYING A HIGH TEMPERATURE BOND COAT ON A METAL SUBSTRATE, AND RELATED COMPOSITIONS AND ARTICLES}
    [3] The present invention relates generally to bond coatings and thermal barrier coatings applied to metals. The metal is often part of components used in turbine engines. The invention also relates to a method for depositing such a coating.
    [4] Parts manufactured by special materials such as superalloys are used in a variety of industrial applications under different working conditions. In many cases, the parts have a coating that imparts some properties such as corrosion resistance, heat resistance, acid resistance and abrasion resistance. For example, various parts of turbine engines that withstand operating temperatures of about 1100 to 1150 ° C. are often covered with a thermal barrier coating (TBC) to efficiently increase the temperature at which they operate.
    [5] Most TBCs are based on ceramics, typically chemically stabilized with other materials such as yttria, for example zirconia (zirconium oxide). For jet engines, the coating is applied to various superalloy surfaces, such as turbine vanes and vanes, combustor liners, and combustor nozzles. Typically, TBC ceramics are applied to an intervening bond coat (often referred to as a "bond layer" or "bond coat") and applied directly to the surface of the metal part. The bond coat is often important for improving the adhesion between the metal substrate and the TBC.
    [6] The efficiency of TBC is often measured by the number of thermal cycles that withstand before delaminating from the protecting substrate. In general, the coating efficiency decreases with increasing exposure temperature. The failure of TBC is due to weakness or defects associated with the bond coat in some way, for example the microstructure of the bond coat. TBC defects result from defects in the bond coat-substrate interface or bond coat-TBC interface.
    [7] The microstructure of the bond coat is often measured by the deposition method. The deposition technique is partly determined by what is required of the protective coating on the stomach. For example, many TBCs typically require very rough bond coat surfaces (e.g., root mean square roughness (Ra) greater than about 200 microinches) for effective adhesion to the substrate. . Air plasma spray (APS) technology is often used to provide this surface.
    [8] There is a continuing need in the art for a bond coat that provides very good adhesion between the substrate and the subsequently applied TBC, for example a bond coat having a relatively rough surface. In addition, new methods for applying and curing such coatings in areas of the substrate that are somewhat inaccessible are also important (sometimes conventional thermal spray devices are too large and cumbersome in these areas). In addition, the overall TBC system-the bond coat comprising the TBC itself-should exhibit good integrity during exposure to high temperatures and frequent thermal cycles. Such systems should be effective in protecting parts used in high performance applications such as superalloy parts exposed to high temperatures and frequent thermal cycles.
    [9] It is therefore an object of the present invention to provide a bond coat and a method of applying the same, a composition and a product comprising the bond coat, which can satisfy the above requirements.
    [1] 1 is a micrograph of a cross section of a comparative coating system comprising a bond coat and a thermal barrier coating (TBC) applied by a conventional method.
    [2] Figure 2 is a micrograph of a cross section of a bond coat / TBC coating system in which a bond coat was applied by slurry technology in accordance with the present invention.
    [10] One embodiment of the present invention
    [11] a) applying a slurry containing a braze material and a volatile component to a substrate,
    [12] b) applying the bond coating material to the substrate,
    [13] c) drying the slurry and bond coat material under conditions sufficient to remove at least a portion of the volatile components, and
    [14] d) fusing the braze material and bond coat material to the substrate;
    [15] A method of applying a bonding coating on a metal substrate.
    [16] The brazing material is typically nickel, cobalt or iron based. The bond coat material is often a "MCrAlX" material or metal carbide as described below.
    [17] There are various methods for applying the bond coat according to the invention. One method is to combine the bond coat material and the braze material with a solvent and one or more additives described below. The combined slurry mixture can then be deposited on the substrate by various techniques, such as flow-coating, brushing or spraying. Optionally, the slurry applied in step (a) comprises a braze material and no bond coat material, and is substantially dried to form a green layer. An adhesive may be applied to the green layer and the bond coat particles may be applied to the adhesive prior to the fusing step. As another alternative embodiment, two separate slurries can be used, one containing the braze material and the other containing the bond coat material. Each slurry may contain the additives described below. In this embodiment, the braze slurry is typically applied first and then the bond coat slurry is applied. The slurry can then be dried and fused to the substrate. Optionally, the overcoat can be applied onto the bond coat. The overcoat is typically of conventional thermal barrier coating, for example zirconium based. Optionally, the overcoat may be of another type, such as a metal carbide based wear coating.
    [18] Methods for replacing the bond coat applied on the metal-based substrate are also discussed later. The following steps are typically included in this method:
    [19] (i) removing the existing bond coat from the selected area on the substrate;
    [20] (ii) applying a slurry comprising a braze material and a volatile component to a selected area;
    [21] (iii) applying additional bond coat material to the selected area; And
    [22] (iv) fusing the braze material and bond coat material to the selected area.
    [23] Such techniques may be part of an overall method for repairing worn or damaged TBC systems.
    [24] Another embodiment of the present invention is directed to a unique slurry composition containing a braze material and a bond coat material along with other conventional slurry components such as solvents. As will be discussed later, the braze material is typically nickel, cobalt, iron, precious metals or mixtures containing one or more of these components. The bond coat material is typically an MCrAlX-type (discussed later), or may be a metal carbide or other type of material. Such slurry compositions are very useful in the formulation of TBC systems.
    [25] Products according to another embodiment of the present invention include:
    [26] (a) a metal-based substrate; And
    [27] (b) a volatile-containing slurry (eg, bond coat particles roughening the surface) on a substrate comprising a braze material and a bond coat material.
    [28] The substrate is often a superalloy and the braze material and bond coat material are as described below. When the volatile components are substantially removed in the slurry, a green film fused to the substrate, for example by soldering, remains. As fused, the braze material forms a continuous matrix phase in which the bond coat particles are embedded.
    [29] Other features and advantages of the invention are apparent from the following detailed description of the invention.
    [30] The braze material used in the present invention may be formed from alloy compositions known and commercially available in the art. Two classes of braze compositions are frequently used. Ie standard liquid soldering and activated diffusion soldering. Sometimes (but not always), the braze alloy has the same composition as the substrate. For example, if the substrate is a nickel-based superalloy, the braze alloy contains at least about 40% nickel by weight along with various other elements such as chromium, aluminum, and yttrium (nickel-containing or cobalt-containing braze alloys are typically Used with cobalt based superalloys). The braze alloy composition also generally contains one or more components to lower its melting point. Examples of melting point depressants for nickel and cobalt based braze alloy compositions are silicon, boron and phosphorus. Silicon or boron, or a combination thereof, is often preferred. The braze alloy composition may also contain other additives known in the art, such as flux formulations. The average particle diameter of the braze alloy is typically about 20 to about 150 μm, and more preferably about 40 to about 80 μm.
    [31] Exemplary nickel- and cobalt-based braze alloy compositions are disclosed in commonly assigned US patent application Ser. No. 09 / 444,737 (W.Hasz), filed November 23, 1999, which is incorporated herein by reference. Preferred nickel-based braze alloy compositions for the present invention comprise from about 5% to about 15% by weight of silicon or boron, and from about 15% to about 25% by weight chromium with the remaining nickel. Sometimes silicon is preferred to boron. Mixtures of silicon and boron are also possible.
    [32] Another type of braze alloy can be used with precious metal compositions containing silver, gold, platinum, and / or palladium, and with other metals such as, for example, copper, manganese, nickel, chromium, silicon and boron. Mixtures comprising at least one braze alloy element are also possible. Many metal braze compositions are commercially available from Praxair Surface Technologies, Inc.
    [33] As mentioned above, the braze material is used in slurry form. The slurry typically contains one or more binders and a solvent. The choice of solvent depends on various factors, such as the ability to dissolve the binder and disperse the braze powder, as well as the manner in which the slurry is applied to the substrate. The braze material is typically dispersed in an aqueous or organic solvent. For example, water, ethanol or other alcohols; Ketones, nitrile solvents such as acetonitrile; Ketone-type solvents such as acetone; Aromatic solvents such as toluene, xylene, or xyleneol; And compatible mixtures thereof. Often, a two-solvent system is preferred, one is solvent attribute-evaporator, the other evaporates more slowly and provides leveling properties (as used herein, the term “volatile component” is generally used in slurries). Solvent (compound solvent). The binder and other components in the slurry will also volatilize or decompose as the fusion temperature approaches as the temperature rises.
    [34] Various binder materials may be used in the slurry, for example in aqueous organic materials (eg polyethylene oxide and various acrylic, or solvent based binders). The slurry also contains various other additives such as dispersants, wetting agents, peptizing agents, stabilizers, precipitation inhibitors, thickeners, plasticizers, emollients, lubricants, surfactants, antifoaming agents and curing modifiers. Generally, the additive is used in an amount of about 0.01 to about 10% by weight, based on the weight of the total slurry composition. One skilled in the art can determine the most effective amount of any additive, without undue effort.
    [35] Conventional details relating to mixtures of such slurries are disclosed in US Pat. No. 4,325,754, which is incorporated herein by reference (slurry compositions are also commercially available). The slurry is applied to the substrate using the various techniques described above. Examples include slip casting, brushing, painting, immersion, flow-coating, roll-coating, spin coating and spraying. This is disclosed in various texts such as Kirk-Othmer, Encyclopedia of Chemical Technology , 4th Edition, Vol. 5, pp. 606-619; Technology of Paints, Varnishes and Lacquers , C. Martens, Reinhold Book Corporation, 1968. US patent application Ser. No. 09 / 378,956, filed August 23, 1999 (D.Sangeeta et al.) Describes some aspects of slurry technology.
    [36] Various types of bond coat materials can be used in the present invention. Most are known in the art. Often, but not always, a "hot" bond coat is desired. The substrate is exposed to an operating temperature of about 500 ° C. or more and more often an operating temperature of about 900 ° C. or more. More frequently, the bond coat material is of type MCrAlX, where M is a variety of metals such as Fe, Ni or Co, or a combination thereof, and "X" is Y, Ta, Si, Hf, Ti, Zr, B, C and Selected from the group consisting of a combination thereof ("X" is typically yttrium). Some of the preferred alloys of this type have a broad composition (% by weight) (M constitutes the remainder) of about 17 to about 23% chromium, about 4 to about 13% aluminum, and about 0.1 to about 2% yttrium. In some embodiments, M is a mixture of nickel and cobalt and the ratio of nickel to cobalt is about 10:90 to about 90:10 weight percent.
    [37] As noted above, other types of bond coat materials may be used. Non-limiting examples include aluminides, platinum-aluminates; Nickel-aluminate; Platinum-nickel-aluminate and mixtures thereof. In addition, mixtures of MCrAlY-type materials and metals such as zirconium or hafnium may also be used. One skilled in the art can select the most appropriate bond coat material based on end use, cost, processing method and other considerations.
    [38] The size of the bond coat particles can vary and is in part related to the desired roughness of the bond coat. Typically, the bond coat particles have an average particle diameter of about 45 μm or more. When subsequent TBCs are to be applied by air plasma spray (often requiring a rough bottom surface), the bond coat particles typically have an average particle diameter of about 150 μm or more. In some preferred embodiments, the bond coat particles have a size of about 150 to about 300 μm. Large particle diameters may be used in some cases, for example, where larger roughness is desired. Occasionally, these particles are referred to herein as "primary bond coat particles" and provide a conventional type of roughness (R a ) discussed later.
    [39] In a preferred embodiment, the bond coat particles have a particular shape, especially in situations where air plasma-injected TBC is to be applied. The shape is sufficient to produce micro-roughness in the bond coat after the material is fused to the substrate with solder. Micro-roughness is divided come roughness (R a) provided by the primary bond coat particles (the conventional roughness is usually measured by a surface shape measurement). Micro-roughness is microscale roughness and folds back on the primary particles. All embodiments of the present invention provide very good adhesion to subsequently applied TBCs. However, the presence of micro-roughness significantly increases the adhesion in many cases during the operating life of the TBC.
    [40] Several methods for obtaining micro-roughness exist and typically involve the use of bond coat powders that are commercially available and known to provide this effect. The micro-roughness may be in the form of smaller spheres of bond coat material (eg, having a size of about 5 to about 50% of the primary particle diameter) connected to the larger primary particles.
    [41] Optionally, the micro-roughness may be in the form of irregular or rough surfaces on the primary particles. In this case, the surface of the primary particles is somewhat saw-blade with the bottom cut off, which is curled and folded back in a certain area. This particle surface has an appearance similar to that produced when a British muffin is torn in half. Particles having such properties (eg, MCrAlX-type compositions) are commercially available.
    [42] In one embodiment of the present invention, the slurry also contains a bond coat material such that the braze material and the bond coat material are applied simultaneously to the substrate. Any conventional technique, such as a mechanical mixer, can be used to join the solder and bond coat materials into one slurry. In addition to the following general safety procedures, care should be taken to maintain each of the metal components well dispersed in the slurry. One or more aqueous or organic solvents are used for the slurry. The choice for a particular solvent or solvent mixture for this embodiment depends in part on the compatibility of the solvent with the braze and bond coat material, as well as any melting point inhibitors that may be present. The solvent must also be able to maintain a substantially dispersed solid component. In addition, the additives (mentioned above) used in the slurry must be compatible with each other along with the other ingredients in the slurry.
    [43] The slurry is typically deposited on a substrate as a single layer. However, if desired, it is desirable to deposit the slurry in the form of two or more "sub-layers" for two or more uses. For example, each sub-layer includes the same composition, but the size of the bonding layer particles may vary. Smaller particles can be used, for example, in sub-layers closer to the substrate for increased film density. Larger particles are used in one or more upper sub-layers to provide the desired amount of roughness (a heat treatment may be applied after application of each sub-layer).
    [44] Optionally, the composition of the two or more sub-layers can be varied to provide different properties at different depths of the bond coat. For example, the braze alloy may contain a standard NiCrAlY-type bond membrane material. The second sub-layer applied on the first sub-layer may contain the braze alloy together with a different bond coat material, for example an MCrAlX-type bond coat material, where M is a mixture of nickel and cobalt. The second sub-layer, which is closer to the atmosphere during operation, should provide greater corrosion resistance than standard NiCrAlY under certain circumstances.
    [45] In a similar manner, two or more sub-layers can be varied to control the extent to which oxidation occurs, for example, oxidation at the bond coat-substrate interface discussed in the Examples. In addition, the composition of the bond coat is gradient or stratified, for example by a metering system, so that changes in a particular configuration are made gradient as the slurry component is applied onto the substrate.
    [46] After the slurry mixture is deposited, at least a portion of the volatile material contained herein is removed. This step is sometimes referred to as the “evaporation step” or “evaporation stage” and produces a substantially devolatile (solvent-free) film, ie a “green” film. Any conventional drying technique is used to remove the volatile components. Drying can include air-drying or vacuum-drying at room temperature. In some cases, it is desirable to heat the slurry mixture to accelerate drying.
    [47] The green film containing the braze material and the bond coat material is then fused to the substrate. The fusion step can be performed by various techniques. Most often, it is a soldering step and similar to any conventional brazing operation (as referred to herein, "soldering" includes any method of joining a metal that generally involves the use of a fill metal or alloy). ). One exemplary reference relating to soldering is as follows: Modern Metalworking, JRWalker, The Goodheart-Willcox Co., Inc., 1965, pp. 29-1 to 30-24. Those skilled in the art will be familiar with other details related to soldering. The brazing temperature depends in part on the braze alloy used and is generally about 525 to about 1650 ° C. In the case of nickel-based braze alloys, the brazing temperature is typically about 800 to about 1260 ° C. If possible, soldering is often performed in a vacuum furnace. The amount of vacuum depends in part on the braze alloy composition. Typically, the vacuum is about 10 −1 to about 10 −8 torr. Vacuum furnace soldering also removes any volatiles (eg, binders) that remain on the green coat. Volatile material content can be measured by various techniques, such as differential thermal analysis (DTA) and thermal gravimetric analysis (TGA).
    [48] In some cases, the slurry should be applied in areas not suitable for use in the furnace. For example, the component itself may be too large to insert into the furnace. In this case, there is an alternative. For example, a torch or other localized heating means can be used. These techniques are known in the art and are briefly disclosed in the commonly assigned patent application of W. Hasz, patent application 09 / 444,737, which was incorporated above and incorporated by reference herein.
    [49] In an optional aspect, the slurry contains an additive that does not contain the braze material and any necessary, but bond coat material. In this case, the slurry is applied to form a green layer and then substantially dried. As described above, any conventional drying technique, such as air drying, may be used before and after selective heat treatment to increase evaporation of volatile components.
    [50] This bond coat material, typically in the form of dry powder particles, is applied onto the green layer. Typically, an adhesive is applied to the surface of the green layer prior to the application of the bond coat powder. Various adhesives can be used as long as they can be fully volatilized during subsequent fusion steps. Some suitable adhesives are disclosed, for example, in the following references, the Condensed Chemical Dictionary, 10th Edition, B. Hawley, Van Nostrand Reinhold Company Inc., 1981, pp. 20-21. Illustrative examples of adhesives include polyethylene oxide and acrylic materials. Commercial examples of soldering adhesives include "4B Braze Binder®", available from Cotronics Corporation. The adhesive can be applied by various techniques. For example, a liquid-type adhesive can be sprayed or coated onto the surface. Thin films or films with double sided adhesives may optionally be used, for example 467 ™ adhesive tapes from 3M Company may be used.
    [51] The bond coat powder may then be applied onto the adhesive by various techniques, such as spraying, pouring, blowing, roll-deposition, and the like. After deposition, excess powder is removed from the substrate (eg, by agitation or by ejection) while substantially maintaining a monolayer of bond coat particles. As explained above, the size of the particles largely depends on the roughness required for the bond coat. The green film (with the solder material) is fused to the substrate as described above. The resulting coating system is substantially the same as that formed in the first embodiment.
    [52] In another alternative embodiment, the bond coat material may be used in the form of a second slurry, ie in a separate form from the slurry containing the braze material. The second slurry is formed of one or more solvents, ie, solvents that are compatible with the particular bond coat composition. The slurry also contains one or more of the other additives described above, such as binders, dispersants, and the like. In addition, the slurry can be applied onto the first slurry by any of the techniques described above, for example by spraying. In a preferred embodiment, some or all of the volatile components in the first slurry are removed prior to application of the second slurry to avoid bubble formation. Removal of volatiles is usually carried out by heating as described above. The volatiles are then removed from the second slurry in the same or similar manner before the fusing step. The resulting coating system is substantially the same as formed in other embodiments.
    [53] In another embodiment, the bond coat may be in the form of a second slurry, which second slurry is premixed with the first slurry. The resulting premix can be applied to the substrate before removal of the volatile components. Fusion is then performed in the manner described above.
    [54] In the same embodiment of the invention, the overcoat is applied onto the bond coat after the bond coat material is fused to the substrate with the braze material. The overcoat is typically a thermal barrier coating, provided it can be any type of coating for protecting the environment, ie protecting the substrate from the adverse effects of oxidation, corrosion or chemical attack. The overcoat may also be a wear resistant coating. In addition, the overcoat is typically ceramic, but optionally metallic.
    [55] Ceramic thermal barrier coatings are often (but not always) zirconia-based. As used herein, “zirconia-based” includes ceramic materials containing at least about 50% by weight of zirconia. Zirconia is a well known compound for barrier coatings. For example, its uses are disclosed in Kirk-Othmer, Encyclopedia of Chemical Technology , 3rd Edition, V.24, pp. 882-883 (1984). In a preferred embodiment, zirconia is chemically stabilized by mixing with yttrium oxide, calcium oxide, magnesium oxide, cerium oxide, scandium oxide or mixtures of these materials. As one specific example, zirconia is mixed with about 1-20 wt% yttrium oxide (based on the combined weight) and preferably with about 3-10 wt% yttrium oxide.
    [56] Various techniques can be used to apply ceramic coatings. Non-limiting examples include thermal spray techniques such as APS, physical vapor deposition (PVD), or electron beam physical vapor deposition (EB-PVD). Those skilled in the art will be familiar with the details of each of these deposition techniques. See Kirk-Othmer's Encyclopedia of Chemical Technology, 3rd Edition, Vol. 15, (1981) and Vol. 20 (1982); Ulmann, Encyclopedia of Industrial Cheminstry, Fifth Editio; Volume A6, VCH Publisher (1986); Scientific American, H. Herman, September 1988; And US Pat. No. 5,384,200. Ceramic slurry techniques or sol gel techniques can also be used to apply ceramic coatings.
    [57] Examples of other types of materials for overcoat include wear resistant coatings such as those formed from carbide coatings such as chromium carbide and tungsten carbide and cobalt-molybdenum-chromium-silicon. Other types of materials can also be used, such as alumina, mullite, zircon and glass type materials such as strontium-calcium-zirconate glass. Those skilled in the art will be able to select the most suitable material for a given end use. Methods for making and applying such materials are those described above for the zirconia TBC, or consist of other techniques well known in the art. In addition, some overcoats may be prepared and applied in slurry form on the bond coat as described above. Slurry-based overcoats are also disclosed in commonly assigned US patent application Ser. No. 09 / 557,393 (D.Sangeeta), filed April 24, 2000, which is incorporated herein by reference. For example, the summary and other sections of the invention of this application are teaching.
    [58] Another embodiment of the present invention is directed to a method of replacing a bond coating previously applied to a metal based substrate. Replacement of the bond coat is often part of the overall method of repairing worn or damaged TBCs. Careful repair of the TBC system (bonded coating and TBC) is important to prevent degradation of the substrate. In the case of turbine engine parts, it is necessary to repair the coating while the turbine is in operation, i.e. after moving from the manufacturing position, for example. The method disclosed herein provides a means for quickly repairing and replacing selected areas of an existing TBC system without having to completely remove the coating from the engine component.
    [59] The steps for replacing the bond coat are typically
    [60] (i) removing the existing bond coat (and worn or damaged overcoat, if present) from selected areas on the substrate;
    [61] (ii) applying a slurry to the selected area that also contains a braze material and volatile components;
    [62] (iii) applying additional bond coat material to the selected area; And
    [63] (iv) fusing the braze material and the bond coat material to the selected region.
    [64] It includes.
    [65] As described above, a single slurry containing a braze material and a bond coat material can be used. Optionally, two separate slurries can be used. Optionally, the braze slurry can be applied and then dried and an adhesive layer applied. The bond coat material may then be applied to the adhesive layer.
    [66] The slurry and bond coat material may be air-dried between steps (iii) and (iv). Heating means, for example IR lamps, can be used to accelerate the removal of volatile components. The fusing step is often performed using a torch or other portable heating device.
    [67] For turbine engine components that include a coating to be repaired, the heat developed during engine operation may be sufficient to remove volatile components and perform fusion step (iv). This means of heating and curing may in fact be delayed until the slurry-based overcut is applied as described below.
    [68] When the overcoat is replaced, the overcoat can then be applied onto the bond coat. Typically, the overcoat (e.g., TBC) will be applied by a thermal spray method in the maintenance setting. Plasma spraying is a common technique. However, the overcoat can optionally be applied on the bond coat in the form of a slurry, as discussed above (Sanjita Patent Application 09 / 557,393). As mentioned above, the turbine engine operating temperature removes all volatiles and fuses all of the braze material and bond coat to the substrate in a single step; The overcoat may be sufficient to cure.
    [69] Another embodiment of the present invention is a slurry composition comprising a braze material and a bond coat material. Such slurries are useful for applying the bond coat as described above. Standard liquid soldering or activated diffusion soldering may be used as the slurry. When the slurry is applied to a nickel-based alloy, the braze alloy typically contains at least about 40% by weight of nickel along with various other elements such as chromium, aluminum, and yttrium. The average particle diameter of the braze alloy is typically from about 20 to about 150 μm as mentioned above.
    [70] The bond coat material in the slurry is typically of the type MCrAlX, as mentioned above. The size of the bond coat material varies somewhat. Often it may have an average particle diameter of about 45 μm or more.
    [71] The solvent selection for the slurry will depend in part on the solid component contained therein and will be applied to the substrate in this manner. Exemplary solvents are mentioned above along with the binding materials and various other additives such as dispersants, wetting agents and stabilizers. The amount of braze material and bond coat in the slurry can be determined by a variety of factors such as the desired thickness of the bond coat, solubility and dispersibility of the bond coat and braze material in a solvent or solvent mixture; And the manner in which the slurry is applied. Typically, the slurry comprises about 20 to about 50 weight percent of the braze material, and about 50 to about 80 weight percent of the bond coat, based on the total slurry weight. The slurry generally contains up to about 10 weight percent solvent and up to about 10 weight percent binder.
    [72] Yet another embodiment of the present invention relates to an article comprising:
    [73] (a) a metal substrate, eg formed of superalloy; And
    [74] (b) A volatile-containing slurry on a substrate comprising a braze material and a bond coat material.
    [75] Certain components found in these slurries have already been described. If the volatile components in the slurry are substantially removed, the green layer remains. The green layer is then fused to the substrate, for example by soldering techniques. In a preferred embodiment, the braze material forms a continuous matrix phase in which the bond coat particles are embedded. The size of the bond coat particles may be selected to protrude out of the matrix. At this time, they are those having a relatively coarse surface, for example Ra of at least about 200 microinches, and preferably at least about 300 microinches of Ra. This surface provides good adhesion to subsequently applied ceramic layers. Products containing such layers, such as zirconia-based TBCs, are also within the scope of the present invention.
    [76] To those skilled in the art to better understand the invention, the following examples are provided for illustrative purposes, but are not intended to be limiting.
    [77] Example 1
    [78] Sample A is for comparison and represents a typical TBC system. The substrate was a coupon made from a nickel-based superalloy. The coupon was grit-blasted and ultrasonically cleaned. The NiCrAlY-type bond coat was then air plasma-sprayed (APS) onto the substrate surface. The nominal bond coat composition was as follows: 68 wt% Ni, 22 wt% Cr, 9 wt% Al, and 1 wt% Y. The thickness of the bond coat was about 5-8 mils (about 127-203 μm). It had an average roughness Ra of about 500 to about 900 microinches. Then TBC (heat barrier coating: yttria-stabilized zirconia, with yttria 8% by weight) was air plasma-sprayed onto the bond coat. TBC thickness was about 10-12 mils (about 254-305 μm).
    [79] Sample B represents an embodiment of the invention. The slurry was prepared by first adding the following components to acetone under stirring.
    [80] (a) The coarse NiCrAlY-type bond coat powder has the optimal composition as follows: 68 wt% Ni, 22 wt% Cr, 9 wt% Al, and 1 wt% Y. The powder is -30 + 100 mesh, i.e. 150 It had an average particle diameter of from 600 μm.
    [81] (b) a high temperature braze powder commercially available as Amdry® 100 having the following suitable composition: 10 wt.% silicone; 19% by weight chromium, basic nickel. The powder had an average particle diameter of about 100 mesh, less than about 150 μm.
    [82] (c) Nicrobraz® 300 binder (Ethyl methacrylate in trichloroethane, Wall Colmonoy, Inc., Madison Heights, Mich., USA).
    [83] The metal powder was dry-mixed (50% by weight of component (a) and 50% by weight of component (b)). Components (c) and (d) were added and mixed (10% by weight of the total slurry weight, respectively).
    [84] The slurry was applied (by brushing) to the same type of superalloy coupon used for Sample A. The wet thickness of the slurry was about 5 mils (127 μm). The slurry was then air-dried for about 12 hours during which at least about 15% by weight of volatiles were removed. The resulting green film was then heated in a vacuum furnace at a soldering temperature of about 1093-1204 ° C. (2000-2200 ° F.) for about 1 hour. A dense, coarse bond coat having a Ra of about 25 μm (about 984 microinches) was produced. The same type of thermal barrier film (zirconia-based) used for Sample A was then air plasma-sprayed onto the bond coat.
    [85] 1 is a cross-sectional micrograph of the coating system for Sample A. FIG. Region II is an oxide region that begins to form between the substrate and the bond coat as a result of the thermal test. Region III represents the general overlap of the bond coat material “splot” resulting from the bond coat itself and resulting from APS deposition. Region IV is TBC.
    [86] The overall coating system of Sample A shows good integrity for the same end use and projected run life. However, region II results from accelerated oxidation at the bond coat-substrate interface towards the end of the simulated operating life. The oxidation ultimately results in film failure since most or all of the TBC and bond coat are desorbed from the substrate.
    [87] 2 is a cross-sectional micrograph of the coating system for Sample B, prepared according to an embodiment of the present invention. The coating system was introduced as sample A in the same amount of thermal test. Region V is a substrate. Region VI is a slurry layer applied and soldered onto the substrate. Region VII is TBC. The absence of the oxidation region shown in FIG. 1 indicates that accelerated oxidation does not occur in the bond coat-substrate.
    [88] The type of thermal test performed for each sample was Furnace Cycle Testing. One cycle was 45 minutes at 2000 ° F. (1093 ° C.). The process continued 300 times for each sample. The results demonstrated that the present invention (Sample B) had a furnace cycle life about three times greater than the comparative baseline sample (Sample A).
    [89] Example 2
    [90] In this example, to prepare Sample C, the same type of substrate was used. A slurry was prepared containing 80% by weight of Amdry® 100 high temperature braze powder with 10% by weight of water and 10% by weight of polyethylene oxide binder. The slurry was applied to the substrate until it had a wet thickness of about 5 mils (127 μm). The slurry was then allowed to dry for about 14-16 hours. About 15% by weight of volatiles were removed in this drying step leaving a green layer. A solder contact adhesive layer (Nicrobraz ™ 300) was then applied onto the green layer.
    [91] The crude NiCrAlY-type bond coat powder (Sample B) used in Example 1 was sprinkled onto the contact adhesive to create a monolayer of the crude powder. Excess bond coat powder was blown off. The coupon was then heated in a vacuum furnace at a soldering temperature of about 1093-1204 ° C. (2000-2200 ° F.) for about 0.25-2 hours to produce a dense, coarse bond coat (Ra of about 25 μm / 984 microinches). The same type of thermal barrier coating (zirconia-based) used in Sample A was then air sprayed onto the bond coating.
    [92] As in Example 1, an FCT test was performed. Sample C exhibited approximately the same properties as Sample B (crack resistance and delamination). In addition, Sample C exhibited no accelerated oxidation at the bond coat-substrate interface as demonstrated for Sample A.
    [93] So far, preferred embodiments have been described as examples. However, the above contents are not intended to limit the present invention. Accordingly, various modifications, adaptations, and alternative embodiments will occur to those skilled in the art without departing from the scope and spirit of the invention.
    [94] All of these patents, articles and documents are incorporated herein by reference.
    [95] According to the present invention, a method and a related product are obtained in which a bonding film is applied onto a substrate, which has good adhesion to the substrate and can maintain good integrity even when exposed to high temperatures and frequent thermal cycles. In addition, it is possible to quickly repair and replace only the selected area without having to completely remove the existing film during the film repair in engine parts and the like.
    权利要求:
    Claims (66)
    [1" claim-type="Currently amended] a) applying a slurry containing a braze material and a volatile component to a substrate,
    b) applying the bond coating material to the substrate,
    c) drying the slurry and bond coat material to remove at least a portion of the volatile components, and
    d) fusing the braze material and bond coat material to the substrate;
    A method of applying a bond coat on a metal substrate.
    [2" claim-type="Currently amended] The method of claim 1,
    And the braze material comprises at least one metal selected from the group consisting of nickel, cobalt, iron, precious metals or mixtures comprising at least one of these components.
    [3" claim-type="Currently amended] The method of claim 2,
    And the braze material comprises at least about 40% nickel by weight.
    [4" claim-type="Currently amended] The method of claim 2,
    And the braze material further comprises a component that lowers the melting point of the braze alloy.
    [5" claim-type="Currently amended] The method of claim 4, wherein
    Wherein said component is silicon, boron or mixtures thereof.
    [6" claim-type="Currently amended] The method of claim 1,
    Wherein the braze material has an average particle diameter of about 20 to about 150 μm.
    [7" claim-type="Currently amended] The method of claim 1,
    Wherein said slurry further comprises one or more additives selected from the group consisting of binders, stabilizers, thickeners, dispersants, peptizers, precipitation inhibitors, plasticizers, emollients, lubricants, surfactants, antifoams, and cure modifiers.
    [8" claim-type="Currently amended] The method of claim 1,
    And said slurry is applied to the substrate by a technique selected from the group consisting of slip casting, brushing, painting, immersion, flow-coating, roll-coating, spin coating and spraying.
    [9" claim-type="Currently amended] The method of claim 1,
    The bond coat material is selected from the group consisting of general formula MCrAlX, wherein M is Fe, Ni, Co and mixtures thereof; X is Y, Ta, Si, Hf, Ti, Zr, B, C and combinations thereof It is selected from the group consisting of.
    [10" claim-type="Currently amended] The method of claim 1,
    And wherein said bond coat comprises a material selected from the group consisting of aluminide, platinum-aluminate, nickel-aluminate, platinum-nickel-aluminate and mixtures thereof.
    [11" claim-type="Currently amended] The method of claim 1,
    Wherein said bond coat material has an average particle diameter of at least about 45 μm.
    [12" claim-type="Currently amended] The method of claim 11,
    Wherein said bond coat material has an average particle diameter of about 150 to about 300 μm.
    [13" claim-type="Currently amended] The method of claim 1,
    Wherein said volatile component comprises at least one aqueous solvent or at least one organic solvent, or mixtures thereof.
    [14" claim-type="Currently amended] The method of claim 1,
    The step (c) is carried out by air-drying.
    [15" claim-type="Currently amended] The method of claim 1,
    Step (d) is carried out at a temperature of about 525 to about 1650 ° C.
    [16" claim-type="Currently amended] The method of claim 1,
    The metal-based substrate is a superalloy.
    [17" claim-type="Currently amended] The method of claim 16,
    The superalloy is a nickel-based or cobalt-based material.
    [18" claim-type="Currently amended] The method of claim 1,
    And wherein said bond coat has a root mean square roughness (Ra) of about 200 microinches or more after step (d).
    [19" claim-type="Currently amended] The method of claim 1,
    Wherein the slurry also includes a bond coat material, such that the braze material and bond coat material are applied simultaneously to the substrate.
    [20" claim-type="Currently amended] The method of claim 19,
    The slurry is selected from the group consisting of a solvent, a binder, a stabilizer, a thickener, a dispersant, a peptizing agent, a precipitation inhibitor, a plasticizer, an emollient agent, a lubricant, a surfactant, an antifoaming agent, and a curing modifier. A method made by combining with one or more additives.
    [21" claim-type="Currently amended] The method of claim 19,
    Wherein the braze material has an average particle diameter of about 20 to about 150 μm and the bond coat material has an average particle diameter of about 45 μm or more.
    [22" claim-type="Currently amended] The method of claim 1,
    A method of forming a green layer prior to application of the bond coat material by substantially drying after the slurry of step (a) has been applied.
    [23" claim-type="Currently amended] The method of claim 22,
    Wherein the adhesive material is applied to the green layer prior to the application of the bond coat material.
    [24" claim-type="Currently amended] The method of claim 23,
    Wherein said bond coat material is in the form of dry particles and is applied to an adhesive material.
    [25" claim-type="Currently amended] The method of claim 24,
    Pour or sprinkle the bond coat material onto the adhesive.
    [26" claim-type="Currently amended] The method of claim 1,
    Wherein said bond coat material is in the form of a second slurry applied in step (b) on top of the slurry applied in step (a).
    [27" claim-type="Currently amended] The method of claim 26,
    Wherein each slurry further comprises one or more additives selected from the group consisting of binders, stabilizers, thickeners, dispersants, peptizers, precipitation inhibitors, plasticizers, emollients, lubricants, surfactants, antifoams, and cure modifiers.
    [28" claim-type="Currently amended] The method of claim 26,
    Wherein each slurry is applied to the substrate by a technique selected from the group consisting of slip casting, brushing, painting, immersion, flow-coating, roll-coating, spin coating and spraying.
    [29" claim-type="Currently amended] The method of claim 1,
    Wherein the bond coat is in the form of a second slurry and the second slurry is premixed with the first slurry to form a premix, wherein the premix is applied to the substrate before step (c).
    [30" claim-type="Currently amended] The method of claim 29,
    Wherein the preliminary mixture is applied to the substrate by a technique selected from the group consisting of slip casting, brushing, painting, immersion, flow-coating, roll-coating, spin coating and spraying.
    [31" claim-type="Currently amended] The method of claim 1,
    The overcoat is applied on the bond coat after step (d).
    [32" claim-type="Currently amended] The method of claim 31, wherein
    The overcoat is a thermal barrier coating.
    [33" claim-type="Currently amended] The method of claim 32,
    The heat shield coating is a zirconia-based method.
    [34" claim-type="Currently amended] The method of claim 32,
    The thermal barrier coating is applied by a thermal spray technique.
    [35" claim-type="Currently amended] The method of claim 34, wherein
    The thermal spraying technique is a plasma spraying method.
    [36" claim-type="Currently amended] The method of claim 31, wherein
    The overcoat is a wear resistant coating.
    [37" claim-type="Currently amended] The method of claim 31, wherein
    The overcoat is a metal carbide; Alumina, mullite, zircon, cobalt-molybdenum-chromium-silicon; Strontium-calcium-zirconate glass; And mixtures thereof.
    [38" claim-type="Currently amended] (I) a slurry comprising a mixture of a volatile component and a braze material containing at least about 40% nickel by weight and a metal aluminide- or MCrAlY- where M is nickel, cobalt or a mixture thereof. Applying to the substrate;
    (II) drying the slurry under conditions sufficient to remove at least some of the volatile components to form a green coating; And
    (III) soldering the green film to a substrate
    A method for applying the bonding coating on a superalloy substrate comprising a.
    [39" claim-type="Currently amended] The method of claim 38,
    Wherein the braze material has an average particle diameter of about 40 to about 80 μm and the bond coat material has an average particle diameter of about 150 to about 300 μm.
    [40" claim-type="Currently amended] The method of claim 38,
    A zirconia-based thermal barrier coating is applied on the bonding coating.
    [41" claim-type="Currently amended] (i) removing the existing bond coat from the selected area on the substrate;
    (ii) applying a slurry comprising a braze material and a volatile component to the selected area;
    (iii) applying additional bond coat material to the selected area; And
    (iv) fusing the braze material and bond coat material to the selected region;
    A method of replacing a bond coating applied on a metal-based substrate, comprising.
    [42" claim-type="Currently amended] 42. The method of claim 41 wherein
    And the slurry further contains a bond coat material such that the braze material and the bond coat material are applied simultaneously to the substrate.
    [43" claim-type="Currently amended] 42. The method of claim 41 wherein
    The bond coat material is selected from the group consisting of general formula MCrAlX, wherein M is Fe, Ni, Co and mixtures thereof; X is Y, Ta, Si, Hf, Ti, Zr, B, C and combinations thereof It is selected from the group consisting of.
    [44" claim-type="Currently amended] 42. The method of claim 41 wherein
    Wherein said metal-based substrate is part of a turbine engine.
    [45" claim-type="Currently amended] A slurry composition comprising a braze material and a bond coat material.
    [46" claim-type="Currently amended] The method of claim 45,
    Wherein said braze material comprises at least one metal selected from the group consisting of nickel, cobalt, iron, precious metals and mixtures containing at least one of these components.
    [47" claim-type="Currently amended] The method of claim 46,
    And wherein the braze material comprises at least about 40 weight percent nickel.
    [48" claim-type="Currently amended] The method of claim 46,
    The bond coat material is selected from the group consisting of general formula MCrAlX, wherein M is Fe, Ni, Co and mixtures thereof; X is Y, Ta, Si, Hf, Ti, Zr, B, C and combinations thereof Selected from the group consisting of;
    [49" claim-type="Currently amended] The method of claim 46,
    The bonding coating is aluminide, platinum-aluminate, nickel-aluminate; Platinum-nickel-aluminate; And a material selected from the group consisting of a mixture thereof.
    [50" claim-type="Currently amended] The method of claim 46,
    Wherein said bond coat material is in the form of particles having an average particle diameter of at least about 45 μm.
    [51" claim-type="Currently amended] (a) a metal-based substrate; And
    (b) a volatile-containing slurry comprising a braze material and a bond coat material on the substrate.
    [52" claim-type="Currently amended] The method of claim 51, wherein
    The substrate is a superalloy.
    [53" claim-type="Currently amended] The method of claim 51, wherein
    Wherein said substrate is part of a turbine engine.
    [54" claim-type="Currently amended] The method of claim 51, wherein
    The braze material comprises at least about 40 weight percent nickel, and the bond coat material is selected from the group consisting of general formula MCrAlX, wherein M is Fe, Ni, Co, and mixtures thereof; X is Y, Ta, Si , Hf, Ti, Zr, B, C, and combinations thereof).
    [55" claim-type="Currently amended] The method of claim 51, wherein
    Wherein said volatile components in the slurry are substantially removed to form a green coating.
    [56" claim-type="Currently amended] The method of claim 55,
    Wherein said green coating is fused to a substrate to form a bond coating.
    [57" claim-type="Currently amended] The method of claim 56, wherein
    And the braze material forms a continuous matrix phase in which the bond coat particles are embedded.
    [58" claim-type="Currently amended] The method of claim 57,
    An overcoat disposed on said bond coat.
    [59" claim-type="Currently amended] The method of claim 58,
    The overcoat is a zirconia-based TBC.
    [60" claim-type="Currently amended] The method of claim 58,
    The overcoat is a wear resistant coating.
    [61" claim-type="Currently amended] (i) a metallic substrate, and
    (ii) a brazed bond coat disposed on the substrate and comprising bond coat particles, wherein the braze material forms a continuous matrix phase and the bond coat particles are embedded on the matrix.
    [62" claim-type="Currently amended] 62. The method of claim 61,
    Wherein said soldered bond coat has a root mean square roughness value Ra of at least about 200 microinches.
    [63" claim-type="Currently amended] 62. The method of claim 61,
    Wherein said soldered bond coat is characterized by micro-roughness.
    [64" claim-type="Currently amended] 62. The method of claim 61,
    The soldered material is nickel-based or cobalt-based.
    [65" claim-type="Currently amended] 62. The method of claim 61,
    Wherein said bonding coating is a hot material.
    [66" claim-type="Currently amended] 62. The method of claim 61,
    A product in which said bond coat particles roughen the surface.
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    同族专利:
    公开号 | 公开日
    JP5345267B2|2013-11-20|
    EP1172460A2|2002-01-16|
    US6497758B1|2002-12-24|
    US20040142112A1|2004-07-22|
    KR20090007258A|2009-01-16|
    EP1172460A3|2004-10-13|
    KR100889126B1|2009-03-16|
    EP1172460B1|2017-03-15|
    JP2002173783A|2002-06-21|
    CZ302983B6|2012-02-01|
    CZ20012549A3|2002-05-15|
    US20030024430A1|2003-02-06|
    US7029721B2|2006-04-18|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2000-07-12|Priority to US09/614,248
    2000-07-12|Priority to US09/614,248
    2001-07-11|Application filed by 제이 엘. 차스킨, 버나드 스나이더, 아더엠. 킹, 제너럴 일렉트릭 캄파니
    2002-01-19|Publication of KR20020006478A
    2009-03-16|Application granted
    2009-03-16|Publication of KR100889126B1
    优先权:
    申请号 | 申请日 | 专利标题
    US09/614,248|2000-07-12|
    US09/614,248|US6497758B1|2000-07-12|2000-07-12|Method for applying a high-temperature bond coat on a metal substrate, and related compositions and articles|
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