Thermal Barrier Coating Compositions, Processes for Applying Same and Articles Coated with Same
A process of coating an article includes the steps of (1) applying a ceramic compound to at least one surface of an article to form a layer of ceramic compound; (2) applying at least one inert compound upon the ceramic compound layer to form a protective layer, wherein the at least one inert compound is composed of a first inert compound having a cubic crystalline structure of formula (I) A3B2X3O12, or a second inert compound comprising a hexagonal crystalline structure of formula (II) A4B6X6O26, or a mixture of the first inert compound and the second inert compound; (3) optionally drying the coated article; (4) optionally repeating steps (2) and (3); and (5) heat treating the coated article.
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This is a divisional application of Ser. No. 11/328,895, filed Jan. 10, 2006, and entitled THERMAL BARRIER COATING COMPOSITIONS, PROCESSES FOR APPLYING SAME AND ARTICLES COATED WITH SAME, the disclosure of which is incorporated by reference herein in its entirety as if set forth at length.
BACKGROUNDThe disclosure relates to thermal barrier coating compositions, processes for applying same and articles coated with same. More particularly, the disclosure relates to thermal barrier coating compositions designed to withstand sand infiltration, processes for applying same and articles coated with same.
The degradation of turbomachinery parts due to sand related distress of thermal barrier coatings (“TBCs”) is a concern with respect to all turbomachinery in use in the Middle East. Sand related distress is responsible for the premature spallation of TBCs and oxidation of turbomachinery and their parts. The mechanism of such sand related distress is the penetration of the TBCs by molten sand. During its useful life, sand may enter the turbomachinery, agglomerate and become molten upon the TBC surface. Typically the surface temperature of the turbomachinery is higher than the melting point temperature of the sand. As a result, the agglomerated sand particles become somewhat molten, penetrate the TBC and reach the ceramic/metallic interface. The failure of the TBC occurs by a combination of molten sand attacking the thermally grown oxide at the ceramic/metallic interface as well as the reduction in strain tolerance, of the fully infiltrated TBC, to thermal cycling. Failure of the TBC occurs by spallation which exposes the part's surface to the elements, thus causing the accelerated oxidation of the turbomachinery part in conjunction with molten sand attack.
Consequently, there exists a need for a thermal barrier coating designed to resist sand related distress.
SUMMARY OF THE DISCLOSUREIn accordance with the present disclosure, a process of coating an article broadly comprising (1) applying a ceramic compound to at least one surface of an article to form a layer of ceramic compound; (2) applying at least one inert compound upon the ceramic compound layer to form a protective layer, wherein the at least one inert compound comprises a first inert compound comprising a cubic crystalline structure of formula (I):
A3B2X3O12 (I)
where A comprises at least one of the metals selected from the group consisting of Ca+2, Gd+3, In+3, Mg+2, Na+, K+, Fe+2, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Zr+4, Hf+4, Gd+3, Al+3, Fe+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, In+3, Sc+2, Y+2, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Fe+3, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen, or a second inert compound comprising a hexagonal crystalline structure of formula (II):
A4B6X6O26 (II)
where A comprises at least one of the metals selected from the group consisting of is Ca+2, Mg+2, Fe+2, Na+, K+, Gd+3, Zr+4, Hf+4, Y+2, Sc+2, Sc+3, In+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Gd+3, Y+2, Sc+2, In+3, Zr+4, Hf+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen, or a mixture of the first inert compound and the second inert compound; and (3) heat treating the article.
In accordance with the present disclosure, a process for coating an article broadly comprising (1) grading a ceramic compound and at least one inert compound upon at least one surface of an article to form a graded thermal barrier coating, wherein the at least one inert compound comprises a first inert compound comprising a cubic crystalline structure of formula (I):
A3B2X3O12 (I)
where A comprises at least one of the metals selected from the group consisting of Ca+2, Gd+3, In+3, Mg+2, Na+, K+, Fe+2, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Zr+4, Hf+4, Gd+3, Al+3, Fe+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, In+3, Sc+2, Y+2, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Fe+3, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen, or a second inert compound comprising a hexagonal crystalline structure of formula (II):
A4B6X6O26 (II)
where A comprises at least one of the metals selected from the group consisting of is Ca+2, Mg+2, Fe+2, Na+, K+, Gd+3, Zr+4, Hf+4, Y+2, Sc+2, Sc+3, In+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Gd+3, Y+2, Sc+2, In+3, Zr+4, Hf+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen, or a mixture of the first inert compound and the second inert compound; and (2) heat treating the article.
In accordance with the present disclosure, a thermal barrier coating broadly comprises a ceramic compound; and at least one inert compound, wherein the at least one inert compound comprises a first inert compound comprising a cubic crystalline structure of formula (I):
A3B2X3O12 (I)
where A comprises at least one of the metals selected from the group consisting of Ca+2, Gd+3, In+3, Mg+2, Na+, K+, Fe+2, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Zr+4, Hf+4, Gd+3, Al+3, Fe+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, In+3, Sc+2, Y+2, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Fe+3, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen, or a second inert compound comprising a hexagonal crystalline structure of formula (II):
A4B6X6026 (II)
where A comprises at least one of the metals selected from the group consisting of is Ca+2, Mg+2, Fe+2, Na+, K+, Gd+3, Zr+4, Hf+4, Y+2, Sc+2, Sc+3, In+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Gd+3, Y+2, Sc+2, In+3, Zr+4, Hf+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen, or a mixture of the first inert compound and the second inert compound.
In accordance with the present disclosure, a coated article broadly comprises an article comprising at least one surface comprising a thermal barrier coating disposed thereupon, wherein the thermal barrier coating broadly comprises a ceramic compound; and at least one inert compound comprising a first inert compound comprising a cubic crystal structure of formula (I):
A3B2X3O12 (I)
where A comprises at least one of the metals selected from the group consisting of Ca+2, Gd+3, In+3, Mg+2, Na+, K+, Fe+2, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Zr+4, Hf+4, Gd+3, Al+3, Fe+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, In+3, Sc+2, Y+2, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Fe+3, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen, or a second inert compound comprising a hexagonal crystalline structure of formula (II):
A4B6X6O26 (II)
where A comprises at least one of the metals selected from the group consisting of is Ca+2, Mg+2, Fe+2, Na+, K+, Gd+3, Zr+4, Hf+4, Y+2, Sc+2, Sc+3, In+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Gd+3, Y+2, Sc+2, In+3, Zr+4, Hf+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen, or a mixture of the first inert compound and the second inert compound.
In accordance with the present disclosure, a coating broadly comprises a reaction product of at least one silicate based material and a thermal barrier coating composition broadly comprising a ceramic compound; and at least one inert compound, wherein said at least one inert compound broadly comprises a first inert compound broadly comprising a cubic crystalline structure of formula (I):
A3B2X3O12 (I)
where A comprises at least one of the metals selected from the group consisting of Ca+2, Gd+3, In+3, Mg+2, Na+, K+, Fe+2, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Zr+4, Hf+4, Gd+3, Al+3, Fe+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, In+3, Sc+2, Y+2, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Fe+3, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen, or a second inert compound comprising a hexagonal crystalline structure of formula (II):
A4B6X6O26 (II)
where A comprises at least one of the metals selected from the group consisting of is Ca+2, Mg+2, Fe+2, Na+, K+, Gd+3, Zr+4, Hf+4, Y+2, Sc+2, Sc+3, In+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Gd+3, Y+2, Sc+2, In+3, Zr+4, Hf+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen, or a mixture of said first inert compound and said second inert compound.
The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.
Like reference numbers and designations in the various drawings indicate like elements.
DETAILED DESCRIPTIONAs used herein, the term “inert compound” means a compound having either a cubic crystalline structure or a hexagonal crystalline structure that exhibits thermodynamic and chemical equilibrium when combined with or makes contact with a ceramic compound, any silicate based material such as, but not limited to, sand, calcia magnesia alumina silicate and the like.
The thermal barrier coating (hereinafter referred to as “TBC”) of the present disclosure is designed to prevent at least one component of sand such as, but not limited to, calcium magnesia alumina silicate (hereinafter referred to as “CMAS”), from penetrating the ceramic compound of the TBC. By preventing/resisting such penetration, premature oxidation of the article and spallation of the TBC are prevented/resisted. Sand generally comprises at least CMAS as well as other components such as, but not limited to, sodium, iron, potassium and the like, depending upon the geographical and geological conditions of the sand. Sands containing iron and CMAS also pose similar problems as described above due to iron-CMAS interaction and penetration to the metallic/ceramic interface of the coated article. The TBC comprises a ceramic compound graded with or mechanically and/or chemically bonded, adhered or affixed to at least one inert compound having either a cubic crystalline structure or a hexagonal crystalline structure.
Referring now to
The bond coat material may also comprise Al, PtAl and the like, that are often known in the art as diffusion coatings. In addition, the bond coat material may also comprise Al, PtAl, MCrAlY as described above, and the like, that are often known in the art as cathodic arc coatings.
The MCrAlY bond coat may be applied by any method capable of producing a dense, uniform, adherent coating of the desired composition, such as, but not limited to, an overlay bond coat, diffusion bond coat, cathodic arc bond coat, etc. Such techniques may include, but are not limited to, diffusion processes (e.g., inward, outward, etc.), low pressure plasma-spray, air plasma-spray, sputtering, cathodic arc, electron beam physical vapor deposition, high velocity plasma spray techniques (e.g., HVOF, HVAF), combustion processes, wire spray techniques, laser beam cladding, electron beam cladding, etc.
The particle size for the bond coat may be of any suitable size, and in embodiments may be between about 15 microns (0.015 mm) and about 60 microns (0.060 mm) with a mean particle size of about 25 microns (0.025 mm). The bond coat 30 may be applied to any suitable thickness, and in embodiments may be about 5 mils (0.127 mm) to about 10 mils (0.254 mm) thick. In some embodiments, the thickness may be about 6 mils (0.152 mm) to about 7 mils (0.178 mm) thick.
After applying the optional bond coat layer to the article, a ceramic compound may be applied upon the optional bond coat layer or at least one surface of the coated article at a box 12 of
Once the TBC is applied, at least one inert compound may be applied upon the TBC at a box 14 of
The TBC and the at least one inert compound may be applied using the same processes, for example, applying both the TBC and the at least one inert compound using a physical vapor deposition process. The TBC and the at least one inert compound may be applied separately such that a TBC may be formed and then a layer of at least one inert compound may be formed upon the TBC. The layers of TBC and at least one inert compound may be mechanically and/or chemically bonded, adhered and/or affixed to as a result of such application processes. Or, the TBC and the at least one inert compound may be applied in combination at a box 32 of
In another embodiment of this process of the present disclosure, the TBC and the at least one inert compound may be applied using different processes at boxes 12 and 14 of
In an alternative embodiment, when applying the at least one inert compound using a solution based process such as sol gel and slurry (e.g., dipping, brushing, painting, etc.), the TBC coated article may be contacted with a solution comprising a suspension at box 14 of
The coated article may then be treated with ultra-violet light energy or heat to cure the resin at a box 16 of
After curing the TBC coated article, the article may be dried to remove, that is, evaporate or burn off, the excess solvent, dispersant and/or resin materials. The article may be dried using any processes known to one of ordinary skill in the art suitable for use herein. Suitable drying processes include, but are not limited to, air drying, drying under pressure, drying under a heating element, combinations comprising at least one of the foregoing processes, and the like. The amount of time necessary to dry the article depends upon several factors and, in particular, the solvent of the suspension. For example, the TBC coated article may be dried at a temperature of about 750° F. to about 1600° F. for about 10 minutes to about 90 minutes in order to burn off the resin materials.
Suitable solvents for use in the suspension include, but are not limited to, water, alcohols, combinations comprising at least one of the foregoing solvents, and the like. Suitable dispersants may comprise organic dispersants which may evaporate and/or burn off easily during the drying step. Representative organic dispersants include, but are not limited to, polymethylmethacrylate (also known as “pmma”), polyvinyl alcohol, and the like. The aforementioned ‘at least one dispersant’ may be present in an amount of about 0.25% to about 3% by volume of the suspension.
An ultra-violet curable resin for use herein may comprise a resin, at least one of each of the following: initiator, additive, modifier, monomer, and oligomer. The resin may comprise a urethane based resin that may require one or more curing steps, for example, a dual curing resin. The at least one initiator may comprise a substance that initiates polymerization of the resin when exposed to ultra-violet light energy of a compatible wavelength. For a dual curing resin, two initiators may be required such that the second initiator may require heat in order to facilitate polymerization of the resin. Dual cure resins are effective when curing coatings where the ultra-violet light energy may not reach the resin material, such as in between the columnar or microcolumnar structures of the coating or at a certain depth in the coating as known to one of ordinary skill in the art. The at least one additive may comprise a filler chemical capable of enhancing one or more resin properties such as, but not limited to, flow rate, wetting, color, fluorescence and achieving tack-free surfaces. The at least one modifier may comprise a substance capable of increasing the durability, for example, impact resistance, crack resistance and the like, of the resin. The at least one monomer may comprise at least one single unit of a polymer capable of providing and/or enhancing adhesion to surface materials, for example, the adhesion of the resin to the surface of the article being coated. The at least one oligomer is recognized as the backbone of the resin and may comprise a polymer unit comprising about 6 to about 40 monomer units that imparts the basic properties of the ultra-violet curable resin such as, but not limited to, hardness, elongation, chemical resistance, and the like. In the alternative, the ultra-violet curable resin may be substituted with at least one heat curable resin as known to one of ordinary skill in the art.
After the TBC and at least one inert compound have been applied to the article, the coated article may be dried at a temperature of about 300° F. to about 750° F. for an amount of time necessary to dry the coating(s) and, if necessary, remove, that is, evaporate and/or burn off, the solvent of the application process at a box 18 of
To facilitate the formation of the respective crystalline structures of the at least one inert compound, the coated article may be heat treated at a temperature of about 1200° F. (649° C.) to about 2000° F. (1093° C.) for about 30 minutes to about 360 minutes at a box 22 of
The thermal barrier composition of the present disclosure formed from the aforementioned processes may comprise the aforementioned ceramic compound and at least one inert compound, including at least one metal oxide formed during the ceramic barrier composition application process. The at least one inert compound may comprise a first inert compound, a second inert compound or a mixture of both the first inert compound and the second inert compound. More than two inert compounds may also be utilized.
The at least one inert compound may comprise an inert compound having a cubic crystalline structure comprising a formula (I):
A3B2X3O12 (I)
where A comprises at least one of the metals selected from the group consisting of Ca+2, Gd+3, In+3, Mg+2, Na+, K+, Fe+2, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Zr+4, Hf+4, Gd+3, Al+3, Fe+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Ac+2, Th+2, Pa+2, U+2, Np+2, Pu+2, Am+2, Cm+2, Bk+2, Cf+2, Es+2, Fm+2, Md+2, No+2, Lr+2, In+3, Sc+2, Y+2, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Fe+3, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen.
The at least one inert compound may also comprise an inert compound having a hexagonal crystalline structure comprising a formula (II):
A4B6X6O26 (II)
where A comprises at least one of the metals selected from the group consisting of is Ca+2, Mg+2, Fe+2, Na+, K+, Gd+3, Zr+4, Hf+4, Y+2, Sc+2, Sc+3, In+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2; where B comprises at least one of the metals selected from the group consisting of Gd+3, Y30 2, Sc+2, In+3, Zr+4, Hf+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen.
The at least one inert compound may also comprise a mixture of the inert compound of formula (I) and the inert compound of formula (II). In at least one embodiment, the inert compound of formula (I) may comprise garnet. In at least one other embodiment, the inert compound of formula (II) may comprise oxyapatite. In yet at least one other embodiment, the aforementioned mixture may comprise both garnet and oxyapatite. Depending upon the application process, the at least one inert compound may be in a form suitable for use in the intended application process. For example, the at least one inert compound may be a fine particulate for use in sol gel, slurry or dipping processes, or may be a coarse particulate for use in a thermal spraying or physical vapor deposition processes, or may comprise a solid target for use in a sputtering process.
The resultant layer of the at least one inert compound, or the resultant graded layer of the ceramic compound and the at least one inert compound, may have a porosity of no more than about 30% by volume of the at least one inert compound or the graded layer, and preferably no more than about 20% by volume of the at least one inert compound or the graded layer. The inert compounds of the present disclosure are inert or non-reactive to all of the ceramic compounds currently used as thermal barrier compositions. In addition, the inert compounds are also inert or non-reactive to at least one component of the molten sand as described above. The inert properties, hardness of garnet and oxyapatite (alone or in combination), and resultant porosity values are enough to prevent the sand and CMAS from penetrating the TBC of the present disclosure and reaching the surface of the coated article.
Referring now to
For example, the article may include, but is not limited to blades, vanes, stators, mid-turbine frames, and the like. And, in yet another example, the article may include, but is not limited to, seals, combustor panels, combustor chambers, combustor bulkhead shields, disk side plates, fuel nozzle guides, and the like.
Generally, coated articles having an airfoil, or a coated airfoil in general, of the present disclosure generally comprise a coating of the present disclosure of about 0.25 mils to about 15 mils in thickness. The coating layer of such thickness may comprise a graded layer or may comprise a layer of the at least one inert compound alone. And, generally, coated articles having a seal, or a coated seal in general, of the present disclosure comprise a coating of the present disclosure of about 0.25 mils to about 50 mils in thickness. The coating layer of such thickness may comprise a graded layer or may comprise a layer of the at least one inert compound alone. These ranges of coating thicknesses for such coated articles of the present disclosure may be broadened or narrowed depending upon the particular application of the article as will be recognized and understood by one of ordinary skill in the art.
The garnet and/or oxyapatite materials alone or in combination with the TBC coatings described herein may react may react with the CMAS, and/or other components, of the molten sand. The reaction product of the CMAS and garnet and/or oxyapatite may comprise further at least one reaction product as more than one reaction product may form during the useful life of the coated article of the present disclosure. For example, a garnet and/or oxyapatite layered or combined with a TBC such as 7YSZ may react with CMAS to form a reaction product comprising at least a complex oxide compound with the garnet crystalline structure and coexist with silicate oxyapatites, including at least simple oxides, less complex oxides and glass.
The reaction product or products form throughout the entirety of the garnet and/or oxyapatite, alone or in combination with the TBC, as the garnet and/or oxyapatite may be dispersed throughout the TBC and the molten sand penetrates through to the coated article's metal/ceramic interface.
The at least one reaction product forms a reaction barrier or sealant composition as a layer upon the TBC or throughout the TBC. The resultant sealant composition remains present as the TBC experiences typical wear and tear, for example, abrasion, erosion, spallation, etc., consistent with general use. Thus, as the TBC wears during its useful life, the sealant composition reforms, remains intact and effectively takes the place of and/or becomes the TBC. The resultant sealant layer may also exhibit the desired porosity of no more than about 30% by volume of the TBC, and preferably no more than about 20% by volume of the TBC.
One or more embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other embodiments are within the scope of the following claims.
Claims
1. A process of coating an article, comprising:
- (1) applying a ceramic compound;
- (2) applying at least one inert compound, wherein said at least one inert compound comprises an inert compound comprising a hexagonal crystalline structure of formula (II): A4B6X6O26 (II) where A comprises at least one of the metals selected from the group consisting of is Ca+2, Mg+2, Fe+2, Na+, K+, Gd+3, Zr+4, Hf+4, Y+2, Sc+2, Sc+3, In+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, Cd+2, and; where B comprises at least one of the metals selected from the group consisting of Gd+3, Y+2, Sc+2, In+3, Zr+4, Hf+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and where O is oxygen; and
- (3) heat treating said article.
2. The process of claim 1, wherein the at least one inert compound further comprises an inert compound comprising a cubic crystalline structure of formula (I):
- A3B2X3O12 (I)
- where A comprises at least one of the metals selected from the group consisting of Ca+2, Gd+3, In+3, Mg+2, Na+, K+, Fe+2, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2;
- where B comprises at least one of the metals selected from the group consisting of Zr+4, Hf+4, Gd+3, Al+3, Fe+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, In+3, Sc+2, Y+2, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3;
- where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Fe+3, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and
- where O is oxygen.
3. The process of claim 1, wherein:
- the applying said ceramic compound comprises applying to at least one surface of an article to form a layer of ceramic compound; and
- the applying said at least one inert compound comprises applying upon said ceramic compound layer to form a protective layer.
4. The process of claim 1, wherein:
- the applying said ceramic and the applying said at least one inert compound comprises grading the ceramic compound and at least one inert compound upon at least one surface of an article to form a graded thermal barrier coating.
5. The process of claim 4, wherein grading comprises forming said graded thermal barrier coating having at least a surface where said at least one inert compound is present in an amount of about 100 percent by weight of said graded thermal barrier coating.
6. The process of claim 1, further comprising (4) drying said article prior to said heat treating (3).
7. The process of claim 6, further comprising (5) repeating steps (2) and (4) prior to said heat treating (3).
8. The process of claim 1, wherein applying said ceramic compound comprises applying said ceramic compound using a process selected from the group consisting of physical vapor deposition, thermal spraying, sputtering, sol gel and slurry.
9. The process of claim 8, wherein said physical vapor deposition process is an electron beam physical vapor deposition process.
10. The process of claim 8, wherein said thermal spraying process is a high velocity oxygen fuel thermal spraying process or an air plasma thermal spraying process.
11. The process of claim 1, wherein heat treating comprises heating said coated article at about 1200° F. to about 2000° F. for about 30 minutes to about 360 minutes.
12. The process of claim 1, wherein said applying said at least one inert compound comprises using a process selected from the group consisting of physical vapor deposition, thermal spraying, sputtering, sol gel, slurry, dipping, brushing, and painting.
13. The process of claim 12, wherein said physical vapor deposition process is an electron beam physical vapor deposition process.
14. The process of claim 12, wherein said thermal spraying process is an air plasma spraying process.
15. The process of claim 12, wherein said thermal spraying process is a high velocity oxygen fuel thermal spraying process.
16. The process of claim 1, wherein the process for applying said ceramic compound to said article is different than the process for applying said inert compound to said ceramic compound layer.
17. The process of claim 1, wherein the process for applying said ceramic compound to said article is the same as the process for applying said inert compound to said ceramic compound layer.
18. The process of claim 1, further comprising the step of applying a layer of bond coat material on at least one surface of said article prior to applying said layer of ceramic compound.
19. The process of claim 18, wherein applying said bond coat layer comprises a process selected from the group consisting of diffusion processes, low pressure plasma-spray, air plasma-spray, sputtering, cathodic arc, electron beam physical vapor deposition, high velocity plasma spray processes, combustion processes, wire spray processes, laser beam cladding, and electron beam cladding.
20. The process of claim 1, wherein applying said at least one inert compound comprises the steps of:
- contacting said article with a suspension of said inert compound, and at least one of each of a dispersant, an ultra-violet curable resin and optionally a surfactant at a temperature of about 68° F. to about 150° F. at a pressure of about 10 torr to about 100 torr for about 2 minutes to about 5 minutes;
- curing said article using ultra-violet light energy for about 10 seconds to about 60 seconds; and
- heat treating said article at a temperature of about 750° F. to about 1600° F. for about 10 minutes to about 90 minutes.
21. The process of claim 1, wherein applying said at least one inert compound comprises the steps of:
- contacting said article with a suspension of said inert compound, and at least one of each of a dispersant, a heat curable resin and optionally a surfactant at a temperature of about 68° F. to about 150° F. at a pressure of about 10 torr to about 100 torr for about 2 minutes to about 10 minutes;
- curing said article at a temperature of about 300° F. for about 20 minutes to about 60 minutes; and
- heat treating said article at a temperature of about 750° F. to about 1600° F. for about 10 to about 90 minutes.
22. A thermal barrier coating comprising:
- a ceramic compound and at least one inert compound, wherein said at least one inert compound comprises a first inert compound comprising a hexagonal crystalline structure of formula (II): A4B6X6O26 (II)
- where A comprises at least one of the metals selected from the group consisting of Ca+2, Mg+2, Na+, K+, Fe+2, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2;
- where B comprises at least one of the metals selected from the group consisting of Gd+3, Y+2, Sc+2, In+3, Sc+2, Y+2, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3;
- where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and
- where O is oxygen.
23. The thermal barrier coating of claim 22, wherein said at least one inert compound comprises a second inert compound comprising a cubic crystalline structure of formula (I):
- A3B2X3O12 (I)
- where A comprises at least one of the metals selected from the group consisting of Ca+2, Gd+3, In+3, Mg+2, Na+, K+, Fe+2, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2;
- where B comprises at least one of the metals selected from the group consisting of Zr+4, Hf+4, Gd+3, Al+3, Fe+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, In+3, Sc+2, Y+2, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3;
- where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Fe+3, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and
- where O is oxygen,
24. The thermal barrier coating of claim 23, wherein said ceramic compound comprises a stabilized zirconate or a stabilized hafnate.
25. The thermal barrier coating of claim 23, wherein said ceramic compound is selected from the group consisting of yttria stabilized zirconia, calcia stabilized zirconia, magnesia stabilized zirconia, yttria stabilized hafnia, calcia stabilized hafnia and magnesia stabilized hafnia.
26. The thermal barrier coating of claim 23, wherein said second inert compound is garnet.
27. The thermal barrier coating of claim 23, wherein said first inert compound is oxyapatite.
28. The thermal barrier coating of claim 23, wherein said at least one inert compound comprises a porosity of no more than about 30% by volume of said at least one inert compound.
29. The thermal barrier coating of claim 23, wherein said at least one inert compound comprises a porosity of no more than about 20% by volume of said at least one inert compound.
30. A coated article comprising:
- an article comprising at least one surface; and
- a thermal barrier coating according to claim 22 disposed thereupon.
31. The coated article of claim 30, wherein said first inert compound comprises a first layer disposed upon a second layer comprising said ceramic compound.
32. The coated article of claim 30, wherein said first inert compound and said ceramic compound comprise a graded layer.
33. The coated article of claim 32, wherein at least at a surface said at least one inert compound is present in an amount of about 100 percent by weight.
34. The coated article of claim 30, wherein said article is selected from the group consisting of blades, vanes, stators, and mid-turbine frames, seals, combustor panels, combustor chambers, combustor bulkhead shields, disk side plates and fuel nozzle guides.
35. The coated article of claim 34, wherein said at least one inert compound comprises a layer having a thickness of about 5 mils to about 15 mils.
36. The coated article of claim 30, further comprising a bond coat material on at least one surface of said article prior to applying said layer of ceramic based compound.
37. A coating, comprising:
- a reaction product of at least one silica based material and a thermal barrier coating composition comprising:
- a ceramic compound; and
- at least one inert compound,
- wherein said at least one inert compound comprises a first inert compound comprising hexagonal crystalline structure of formula (II): A4B6X6O26 (II)
- where A comprises at least one of the metals selected from the group consisting of is Ca+2, Mg+2, Fe+2, Na+, K+, Gd+3, Zr+4, Hf+4, Y+2, Sc+2, Sc+3, In+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2;
- where B comprises at least one of the metals selected from the group consisting of Gd+3, Y+2, Sc+2, In+3, Zr+4, Hf+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3;
- where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and
- where O is oxygen.
38. The coating of claim 37 wherein said at least one inert compound further comprises a second inert compound comprising a cubic crystalline structure of formula (I):
- A3B2X3O12 (I)
- where A comprises at least one of the metals selected from the group consisting of Ca+2, Gd+3, In+3, Mg+2, Na+, K+, Fe+2, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, Sc+2, Y+2, Ti+2, Zr+2, Hf+2, V+2, Ta+2, Cr+2, W+2, Mn+2, Tc+2, Re+2, Fe+2, Os+2, Co+2, Ir+2, Ni+2, Zn+2, and Cd+2;
- where B comprises at least one of the metals selected from the group consisting of Zr+4, Hf+4, Gd+3, Al+3, Fe+3, La+2, Ce+2, Pr+2, Nd+2, Pm+2, Sm+2, Eu+2, Gd+2, Tb+2, Dy+2, Ho+2, Er+2, Tm+2, Yb+2, Lu+2, In+3, Sc+2, Y+2, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3;
- where X comprises at least one of the metals selected from the group consisting of Si+4, Ti+4, Al+4, Fe+3, Cr+3, Sc+3, Y+3, V+3, Nb+3, Cr+3, Mo+3, W+3, Mn+3, Fe+3, Ru+3, Co+3, Rh+3, Ir+3, Ni+3, and Au+3; and
- where O is oxygen.
Type: Application
Filed: Nov 2, 2009
Publication Date: Feb 25, 2010
Applicant: UNITED TECHNOLOGIES CORPORATION (Hartford, CT)
Inventors: Kevin W. Schlichting (South Glastonbury, CT), David A. Litton (West Hartford, CT), Michael J. Maloney (Marlborough, CT), Melvin Freling (West Hartford, CT), John G. Smeggil (Simsbury, CT), David B. Snow (Glastonbury, CT)
Application Number: 12/610,393
International Classification: F01D 5/28 (20060101); C23C 14/34 (20060101); C23C 4/10 (20060101); B05D 3/02 (20060101); B32B 9/00 (20060101); B05D 7/00 (20060101); E04B 1/80 (20060101); F01D 9/02 (20060101); F23R 3/00 (20060101); F02C 7/22 (20060101);