Environmental-resistant coating, turbine vane or blade, or turbine engine component, environmental-resistant coating system, and method for protecting ceramic matrix composite

Abstract

To provide an environmental-resistant coating or an environmental-resistant coating system.SOLUTION: A bond coat layer comprises an oxide matrix. Throughout the oxide matrix are dispersed: an oxide-gettering phase; a SiO2-based phase that may be amorphous or crystalline; a crystalline phase; and an amorphous oxide phase that serves as a self-healing phase capable of softening or melting at a predetermined temperature below the melting temperature of the oxide matrix and flowing into cracks formed in the oxide matrix. The amorphous oxide phase includes an alkaline earth aluminosilicate glass, and the crystalline phase includes Al6Si2O13, ZrSiO4, HfSiO4, Ca2ZrSi4O12, Ca2HfSi4O12, CaAl2Si2O8, CaSiO3, Al2TiO5, Mg2Al4Si5O18, BaAl2Si2O8, BaZrSi3O9, Y2Si2O7, Yb2Si2O7, and / or Al2O3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The subject matter of the invention disclosed herein relates to environmental barrier coatings (EBCs) that are resistant to high temperatures through multi-component bond coats. [Background technology]

[0002] Environmental barrier coatings improve the durability of high-temperature components in turbine and engine components, as well as exhaust systems in general, such as combustor liners, engine seals in particular, and blade coatings. These coating systems have a bond coat layer designed to restrict the ingress of oxidizers, such as oxygen and water vapor, from the combustion gases into the ceramic matrix composite (CMC). The durability and effectiveness of EBCs can be limited by the presence of microcracks in the bond coat, which can act as pathways for oxidizers and defects for delamination propagation.

[0003] For example, a coating disclosed in US Pat. No. 5,649,999 addresses some of the above-mentioned problems. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 11,505,506 Summary of the Invention [Problem to be solved by the invention]

[0005] One problem that the present invention seeks to solve is to realize, among the many advantages of the inventive subject matter disclosed herein, the combination of components in a coating system that self-heals when cracks form in the environmental barrier coating, thereby improving the durability of the EBC by using a bond coat to reduce oxidant ingress and slow the rate of degradation of the underlying silicon-containing substrate, e.g., CMC. [Means for solving the problem]

[0006] 1. An environmental barrier coating having a bond coat layer, the bond coat layer including an oxide matrix, the oxide matrix having therein: i) an oxide gettering phase that forms silicon oxide, i.e., forms SiO2 upon reaction with an oxidizing agent; ii) a SiO2-based phase, which may be amorphous or crystalline; iii) a crystalline phase; iv) an amorphous oxide phase, which is a self-repairing phase that softens or melts at a predetermined temperature that is lower than the melting temperature of the oxide matrix and has the ability to flow into cracks formed in the oxide matrix, is dispersed therein; the amorphous oxide phase comprises an alkaline earth aluminosilicate glass; The above crystalline phase is Al6Si2O 13 , ZrSiO4, HfSiO4, Ca2ZrSi4O 12 , Ca2HfSi4O 12 , CaAl2Si2O8, CaSiO3, Al2TiO5, Mg2Al4Si5O 18 , BaAl2Si2O8, BaZrSi3O9, Y2Si2O7, Yb2Si2O7, and / or Al2O3, and if the SiO2-based phase in ii) is amorphous, the crystalline phase may further include crystalline SiO2 in addition to the aforementioned candidates.

[0007] In any of the embodiments disclosed herein for environmental barrier coatings having a bond coat layer, the SiO may be present as a glass or as a crystalline phase in the cristobalite, tridymite, or quartz polymorphs.

[0008] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the alkaline earth aluminosilicate glass may be present as a magnesium aluminosilicate glass, a calcium aluminosilicate glass, a barium aluminosilicate glass, or a strontium aluminosilicate glass, or a mixture thereof. The mixture may include a barium magnesium aluminosilicate glass or a calcium magnesium aluminosilicate glass.

[0009] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the amorphous oxide phase comprises a calcium aluminosilicate glass having an incipient melting point between 1150°C and 1300°C, a viscosity at 1300°C between 200 and 20,000 Pa·s, and a viscosity at 1500°C between 1 and 500 Pa·s, the calcium aluminosilicate glass optionally doped with one or more rare earth or transition metal elements.

[0010] In any of the embodiments disclosed herein relating to an environmental barrier coating having a bond coat layer, the amorphous oxide phase can include a barium-magnesium aluminosilicate glass.

[0011] In any of the embodiments disclosed herein relating to an environmental barrier coating having a bond coat layer, the environmental barrier coating may comprise, in the bond coat layer: The oxide matrix is ​​contained in an amount of 1 to 30% by volume, for example, 5 to 30% by volume, 5 to 25% by volume, 5 to 20% by volume, 10 to 30% by volume, 10 to 20% by volume, 20 to 25% by volume, and 25% by volume (including when any one of these values ​​is independently specified); i) the oxide gettering phase is 25 to 75 volume %, for example, 40 to 75 volume %, 40 to 70 volume %, 50 to 60 volume %, and 50 volume % (including when any one of these values ​​is independently specified); ii) the crystalline phase is 5 to 50% by volume, for example, 10 to 30% by volume, 20 to 25% by volume, and 25% by volume (including when any one of these values ​​is independently specified); iii) The amorphous oxide phase is 1 to 10% by volume, for example, 1 to 10% by volume, 3 to 5% by volume, and 5% by volume (including the case where any one of these values ​​is independently specified).

[0012] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the oxide matrix can be SiO2.

[0013] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the oxide gettering phase may be Si x O y C z where 0.5≦x<1, 0≦y<2, 0≦z<2), or may be Si3N4 or SiCN.

[0014] In a multi-phase equilibrium, one of the phases present is silicon oxide (SiO2). The composition of the gettering phase can also be selected to react with oxidizing species to form an SiO2 oxide scale that is in equilibrium with the mixture. Some or all of the listed gettering particles perform their gettering function by reacting with oxidizing species (e.g., O2 and HO) to form an SiO2 reaction product, which is an oxide scale that grows on the surface of the particle.

[0015] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the oxide gettering phase can be SiC.

[0016] Table 1 provides a list of embodiments in which the self-healing glass is calcium aluminosilicate based, with SiC as the gettering phase, and in certain embodiments, ZrSiO4 phase, mullite (Al6SiO2O 13 ) phase, Ca2ZrSi4O 12The phases include CaO, zirconia (ZrO2), and CaAl2Si2O4 (anorthite). Using the thermodynamic database FactSage, the volume fraction of the liquid (molten oxide) is calculated at 1300°C and 1500°C, and the corresponding viscosity is calculated at each temperature. Here, CAS-A is 26% CaO, 15% AlO 1.5 , and 59% SiO2, and CAS-B is 15% CaO, 30% AlO 1.5 , and 55% SiO2, and CAS-C is 20% CaO, 30% AlO 1.5 , and 50% SiO2.

[0017] [Table 1]

[0018] Table 2 provides a list of embodiments in which the self-healing glass is calcium aluminosilicate based, with SiC as the gettering phase, and in certain embodiments, the HfSiO4 phase, mullite (Al6SiO2O 13 ) phase, Ca2HfSi4O 12 phase, zirconia HfO2 phase, and / or anorthite (CaAl2Si2O4) phase.

[0019] [Table 2]

[0020] Table 3 provides a list of embodiments in which the self-healing glass is based on barium magnesium aluminosilicate with SiC as the gettering phase, and in certain embodiments, zircon (ZrSiO4), mullite (Al6SiO2) 13 ) phase, cordierite (Mg2Al4Si5O 18 ) phase, zirconia (ZrO2), and / or celsian (BaAl2Si2O4). Using the thermodynamic database FactSage, the liquid (molten oxide) volume fraction is calculated at 1300°C and 1500°C, and the corresponding viscosity is calculated at each temperature.

[0021] [Table 3]

[0022] In any of the embodiments disclosed herein relating to an environmental barrier coating having a bond coat layer, the bond coat layer may comprise: 50% by volume of a SiC gettering phase; 25% by volume of ZrSiO4, 20% by volume of SiO2 matrix phase; and 5 volume percent of a self-healing phase made of calcium aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0023] In any of the embodiments disclosed herein relating to an environmental barrier coating having a bond coat layer, the bond coat layer may comprise: 50% by volume of a SiC gettering phase; 25% by volume of Ca2HfSi4O 12 and, 20% by volume of SiO2 matrix phase; and 5 volume percent of a self-healing phase made of calcium aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0024] In any of the embodiments disclosed herein relating to an environmental barrier coating having a bond coat layer, the bond coat layer may comprise: 40 to 70 volume % of a SiC gettering phase; 10-30% by volume of ZrSiO4, 10 to 30 volume % of an SiO2 matrix phase; and 5 to 10 volume % of a self-repairing phase made of calcium aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0025] In any of the embodiments disclosed herein relating to an environmental barrier coating having a bond coat layer, the bond coat layer may comprise: 40 to 70 volume % of a SiC gettering phase; 5 to 50 volume percent ZrSiO4, 5 to 20 volume percent of an SiO2 matrix phase; and 1 to 10 volume % of a self-repairing phase made of calcium aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0026] In any of the embodiments disclosed herein relating to an environmental barrier coating having a bond coat layer, the bond coat layer may comprise: 50% by volume of a SiC gettering phase; 25% by volume of Al6Si2O 13 and, 20% by volume of SiO2 matrix phase; and 5 volume percent of a self-healing phase made of calcium aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0027] In any of the embodiments disclosed herein relating to an environmental barrier coating having a bond coat layer, the bond coat layer may comprise: 50% by volume of a SiC gettering phase; 20-25% by volume of Al6Si2O 13 and, 20-25% by volume of SiO2 matrix phase; and 3 to 5 volume percent of a self-repairing phase made of a rare earth aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0028] In any of the embodiments disclosed herein relating to an environmental barrier coating having a bond coat layer, the bond coat layer may comprise: 40 to 70 volume % of a SiC gettering phase; 5 to 50 volume percent ZrSiO4, 5 to 20 volume percent of an SiO2 matrix phase; and 1 to 10 volume % of a self-repairing phase made of ytterbium aluminosilicate glass having an initial melting point of 1350°C to 1500°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0029] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the oxide gettering phase, crystalline phase, and / or amorphous oxide phase may be dispersed in the oxide matrix in the form of discrete particles.

[0030] In any of the embodiments disclosed herein relating to an environmental barrier coating having a bond coat layer, the crystalline phase is CaHfSiO 12 may include:

[0031] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the crystalline phase is MgAlSiO 18 may include:

[0032] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the crystalline phase may include BaAl2Si2O8.

[0033] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the crystalline phase can include BaZrSi3O9.

[0034] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the crystalline phase is MgAlSiO 18 and the crystalline phase may coexist in equilibrium with a MAS glass containing higher concentrations of MgO and Al2O3.

[0035] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the crystalline phase may include BaAlSiO, which may coexist in equilibrium with a BAS glass having higher concentrations of BaO and AlO.

[0036] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the crystalline phase may include BaZrSiO, and the crystalline phase may coexist in equilibrium with a BAS glass having a higher concentration of BaO and a lower concentration of AlO.

[0037] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, Y2Si2O7 can be an additive in the Y2O3-Al2O3-SiO2 glass.

[0038] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, Yb2Si2O7 can be an additive in the Yb2O3-Al2O3-SiO2 glass.

[0039] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, a mixture of Y2Si2O7 and Yb2Si2O7 can be the additive(s) for the Y2O3-Yb2O3-Al2O3-SiO2 glass.

[0040] In any of the embodiments disclosed herein for an environmental barrier coating having a bond coat layer, the rare earth silicate can be an additive in a rare earth-Al2O3-SiO2 glass.

[0041] An engine component having any of the coatings described herein, including but not limited to, a turbine vane or blade, or a turbine engine component, having any of the coatings described herein on its surface.

[0042] 1. An environmental barrier coating system on a silicon-containing material, comprising a bond coat layer and a protective top coat thereon, the bond coat layer comprising: comprising an oxide matrix, The entire oxide matrix is i) an oxide gettering phase that forms silicon oxide, i.e., forms SiO2 upon reaction with an oxidizing agent; ii) a SiO2-based phase, which may be amorphous or crystalline; iii) a crystalline phase; iv) an amorphous oxide phase, which is a self-repairing phase that softens or melts at a predetermined temperature that is lower than the melting temperature of the oxide matrix and has the ability to flow into cracks formed in the oxide matrix, is dispersed therein; the amorphous oxide phase comprises a calcium aluminosilicate glass or a barium-magnesium aluminosilicate glass; The above crystalline phase is Al6Si2O 13 , ZrSiO4, HfSiO4, Ca2ZrSi4O 12 , Ca2HfSi4O 12 , CaAl2Si2O8, CaSiO3, Al2TiO5, Mg2Al4Si5O 18 , BaAl2Si2O8, BaZrSi3O9, Y2Si2O7, Yb2Si2O7, and / or Al2O3, and when the SiO2-based phase in ii) is amorphous, the crystalline phase may further include crystalline SiO2 in addition to the aforementioned candidates.

[0043] In any of the embodiments disclosed herein relating to environmental barrier coating systems on silicon-containing materials, the alkaline earth aluminosilicate glass may be present as a magnesium aluminosilicate glass, a calcium aluminosilicate glass, a barium aluminosilicate glass, or a strontium aluminosilicate glass, or a mixture thereof. The mixture may include a barium magnesium aluminosilicate glass or a calcium magnesium aluminosilicate glass.

[0044] In any of the embodiments disclosed herein relating to environmental barrier coating systems on silicon-containing materials, the silicon-containing material can be a ceramic matrix composite.

[0045] In any of the embodiments disclosed herein for environmental barrier coating systems on silicon-containing materials, the topcoat may comprise a binary or multi-component oxide, HfO2, ZrO2, Gd2Hf2O7, Gd2Zr2O7, a refractory metal oxide, a silicate, a rare earth mono- or disilicate, an alkaline earth aluminosilicate, or a hafnium or zirconium silicate.

[0046] A method of protecting a ceramic matrix composite material, comprising applying a bond coat layer and a top coat thereover, the bond coat layer comprising: comprising an oxide matrix, The entire oxide matrix is i) an oxide gettering phase that forms silicon oxide, i.e., forms SiO2 upon reaction with an oxidizing agent; ii) a SiO2-based phase, which may be amorphous or crystalline; iii) a crystalline phase; iv) an amorphous oxide phase, which is a self-repairing phase that softens or melts at a predetermined temperature that is lower than the melting temperature of the oxide matrix and has the ability to flow into cracks formed in the oxide matrix, is dispersed therein; the amorphous oxide phase comprises a calcium aluminosilicate glass or a barium-magnesium aluminosilicate glass; The above crystalline phase is Al6Si2O 13 , ZrSiO4, HfSiO4, Ca2ZrSi4O 12 , Ca2HfSi4O 12 , CaAl2Si2O8, CaSiO3, Al2TiO5, Mg2Al4Si5O 18 , BaAl2Si2O8, BaZrSi3O9, Y2Si2O7, Yb2Si2O7, and / or Al2O3, and when the SiO2-based phase in ii) is amorphous, the crystalline phase may further include crystalline SiO2 in addition to the aforementioned candidates.

[0047] In any of the embodiments disclosed herein relating to methods of protecting ceramic matrix composites, the alkaline earth aluminosilicate glass may be present as a magnesium aluminosilicate glass, a calcium aluminosilicate glass, a barium aluminosilicate glass, or a strontium aluminosilicate glass, or a mixture thereof. The mixture may include a barium magnesium aluminosilicate glass or a calcium magnesium aluminosilicate glass. [Brief explanation of the drawings]

[0048] [Figure 1] FIG. 1 illustrates a coating system. [Figure 2] FIG. 1 shows the phase makeup of Particular Embodiment 2 of Table 1 as a function of temperature. [Figure 3] FIG. 1 shows viscosity as a function of temperature for slag (molten oxide) present in Example 2 of Table 1. [Figure 4] FIG. 1 shows the phase makeup of Particular Embodiment 2 of Table 2 as a function of temperature. [Figure 5] FIG. 1 shows viscosity as a function of temperature for slag (molten oxide) present in Example 2 of Table 1. DETAILED DESCRIPTION OF THE INVENTION

[0049] Disclosed herein are environmental barrier coatings that include bond coat system(s) that contain a gettering phase, a crystalline phase or phases, and a self-healing amorphous oxide phase that inhibits the influx of oxidants into the CMC by flowing into microcracks in the coating at the operating temperatures of the component.

[0050] The bond coat contains a gettering phase, a crystalline phase or phases, and a self-healing amorphous oxide phase in a matrix, such as a SiO2 matrix.

[0051] The matrix of the bond coat, ie, the bond coat matrix, may have a porosity of 1-30% or 5-20%.

[0052] In one embodiment, the gettering phase, the crystalline phase or phases, and the self-repairing amorphous oxide phase each exist as particles that are independent and separate from one another; in other words, the gettering phase exists as discrete particles that are not bonded to or melted by either the crystalline phase or the self-repairing amorphous oxide phase.

[0053] In alternative embodiments, the self-repairing phase and the matrix phase may be bonded or chemically attached to the gettering phase.

[0054] Furthermore, when exposed to high temperatures, the matrix phase is likely to be diluted into the self-repairing phase over time.

[0055] It should be noted that when the self-healing phase is incorporated into the coating, it is provided as crushed oxide particles, but the self-healing phase migrates during processing and use of the coating and does not remain in its original location. By reducing the original size of the particles, more uniform distribution and improved performance of the coating may be achieved.

[0056] The gettering phase has a relatively large particle size, adjusted to correspond to the life of the coating.

[0057] In one embodiment, the oxide gettering phase is Si x O y C z (where 0.5≦x<1, 0≦y<2, 0≦z<2), for example SiC. Alternative candidates include Si3N4 or SiCN.

[0058] The self-healing behavior is controlled by the initial melting temperature of the self-healing amorphous oxide phase, which can be glass, and the temperature-dependent viscosity of the glass. The initial melting temperature is lower than the operating temperature of the coating at critical locations on the component, so that a remelting condition occurs periodically. Furthermore, the composition of the glass is such that the viscosity is low enough to flow into cracks during operation, but not so low that the glass flows into adjacent materials, such as a topcoat or CMC.

[0059] The crystalline phase(s) minimize the volume of the SiO2 matrix where microcracks can occur, i.e., the addition of particulate crystalline material makes the matrix even more durable than expected. The interaction between the crystalline phase and the self-healing glass tends to shift the composition of the glass, a shift governed by chemical thermodynamics. Thus, the composition of the coating is controlled not just by the initial configuration, but also by the reaction and intermixing of phases. The criteria for achieving the desired self-healing glass properties are achieved through the compositional range of the system.

[0060] Suitable candidates for the crystalline phase are Al6Si2O 13 , ZrSiO4, HfSiO4, Ca2ZrSi4O 12 , Ca2HfSi4O 12 , CaAl2Si2O8, CaSiO3, Al2TiO5, Mg2Al4Si5O 18 , BaAl2Si2O8, BaZrSi3O9, Y2Si2O7, Yb2Si2O7, and / or Al2O3.

[0061] It should be noted that environmental protection layers applied to the surface of components exposed to high temperature conditions, such as those in turbines, will change slightly over time as a result of the melting and remelting of amorphous oxide phases that migrate / flow into microcracks that develop during use of the component. In this regard, the initial particulate glass, e.g., amorphous oxide phase, in the EBC coating may take on various forms as cracks develop and may fuse with various other particulate components in the SiO2 matrix.

[0062] The self-healing phase can include alkali and alkaline earth aluminosilicates, rare earth aluminosilicate glasses, SiO2 itself, and representative glasses / glass-ceramics such as barium aluminosilicate (BAS), barium-magnesium aluminosilicate (BMAS), lithium aluminosilicate (LAS), strontium aluminosilicate (SAS), ytterbium aluminosilicate, etc. Note that SiO2 itself has a very high melting temperature and is crystalline after processing, but can be incorporated and diluted into the self-healing phase at lower temperatures.

[0063] The component protected by the coating may be composed of a silicon-containing material, such as a ceramic matrix composite, a monolithic ceramic, a silicon-based or silicon-containing ceramic substrate, or a silicon-containing metal alloy. In exemplary embodiments, the protected component may be a silicon-containing ceramic material, such as silicon carbide, silicon nitride, silicon oxynitride, silicon aluminum oxynitride, or combinations thereof. According to certain embodiments, the silicon-containing ceramic substrate comprises a silicon-containing matrix containing a reinforcing material, such as fibers or particles, and more specifically, a fiber-reinforced silicon-based matrix. Particularly suitable ceramic substrates include silicon carbide fiber-reinforced silicon carbide matrix, carbon fiber-reinforced silicon carbide matrix, and silicon carbide fiber-reinforced silicon nitride matrix. Particularly useful silicon-metal alloys include molybdenum-silicon alloys, niobium-silicon alloys, iron-silicon alloys, and alloys of zirconium, hafnium, titanium, chromium, tungsten, boron, platinum, and tantalum.

[0064] The topcoat is resistant to metal loss from Si-containing volatile species when exposed to water vapor or steam, for example, in a steam turbine. The topcoat may include a binary or multi-component oxide, a refractory metal oxide, such as HfO2, ZrO2, or Gd2Hf2O7, Gd2Zr2O7, etc. In other exemplary embodiments, the topcoat may include a silicate with low (lower) SiO2 activity. In another exemplary embodiment, the topcoat may include a rare earth (RE) monosilicate, a rare earth (RE) disilicate, and an alkaline earth (AE) aluminosilicate, hafnium, and zirconium silicate. Furthermore, the topcoat may also have multiple phases and may contain mixtures of any of the above, including mixtures of two, three, four, or more of any of the above.

[0065] Additionally, the topcoat may have porosity, although in some cases the porosity (if any) may be very low.

[0066] The thickness of the topcoat can be at least 0.5 mils (0.0005 inches), for example, 3 to 30 mils or 3 to 5 mils, for example, 2 mils to 3 mils, 3 mils to 4, 5, or 6 mils, 4 mils to 5 or 6 mils, including various combinations of upper and lower limits between 3 and 30 mils.

[0067] The thickness of the environmental barrier coating may be in the range of 3 to 30 mils.

[0068] The topcoat can be applied by thermal spraying techniques, including air plasma spraying, suspension plasma spraying, low pressure or vacuum plasma spraying, high velocity oxygen or air fuel spraying, flame spraying, vapor deposition techniques, including atomic layer deposition, chemical vapor deposition, electron beam physical vapor deposition, and the like.

[0069] In an alternative embodiment, the topcoat and environmental barrier coating may each be applied by a slurry-based method, including dip coating, spray coating, painting, electrophoretic deposition, and the like.

[0070] Specific embodiments: Embodiment 1 1. A multi-layer EBC having a bond coat layer, the bond coat layer comprising: 75% by volume of a SiC gettering phase; 20% by volume of SiO2 matrix phase; and 5% by volume of a self-healing phase made of calcium aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C. (Note that the silica becomes crystalline after treatment and no other additional crystalline phases are present in this embodiment).

[0071] Embodiment 2 1. A multi-layer EBC having a bond coat layer, the bond coat layer comprising: 50% by volume of a SiC gettering phase; 25% by volume of ZrSiO4, 20% by volume of SiO2 matrix phase; and 5% by volume of a self-healing phase made of calcium aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C. In one embodiment, this embodiment is part of a broader range of embodiments, 40 to 70 volume % of a SiC gettering phase; 10-30% by volume of ZrSiO4, 10 to 30 volume % of an SiO2 matrix phase; and 5 to 10 volume percent of a self-healing phase made of calcium aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0072] Embodiment 2b 1. A multi-layer EBC having a bond coat layer, the bond coat layer comprising: 40 to 70 volume % of a SiC gettering phase; 5 to 50 volume percent ZrSiO4, 5 to 20 volume percent of an SiO2 matrix phase; and 1 to 10 volume % of a self-repairing phase made of calcium aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0073] Embodiment 3 1. A multi-layer EBC having a bond coat layer, the bond coat layer comprising: 50% by volume of a SiC gettering phase; 25% by volume of Al6Si2O 13 and, 20% by volume of SiO2 matrix phase; and 5 volume percent of a self-healing phase made of calcium aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0074] Embodiment 4. 1. A multi-layer EBC having a bond coat layer, the bond coat layer comprising: 50% by volume of a SiC gettering phase; 20-25% by volume of Al6Si2O 13 and, 20-25% by volume of SiO2 matrix phase; and 3 to 5 volume percent of a self-repairing phase made of a rare earth aluminosilicate glass having an initial melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0075] Embodiment 5. 1. A multi-layer EBC having a bond coat layer, the bond coat layer comprising: 40 to 70 volume % of a SiC gettering phase; 5 to 50 volume percent ZrSiO4, 5 to 20 volume percent of an SiO2 matrix phase; and 1 to 10 volume % of a self-repairing phase made of ytterbium aluminosilicate glass having an initial melting point of 1350°C to 1500°C, a viscosity of 1,000 to 50,000 Pa·s at 1260°C, and a viscosity of 10 to 500 Pa·s at 1482°C.

[0076] Implementations of the inventive concepts disclosed herein may be better understood by consideration of the following detailed description. Such description refers to the accompanying drawings, which are not necessarily to scale and in which some features may be exaggerated, some features omitted, or represented diagrammatically for clarity. Like reference numerals in the drawings may represent and refer to the same or similar elements, features, or functions.

[0077] More specifically, Figure 1 shows a coating system (100) on a CMC component / substrate (130) that includes a bond coat (120) containing particles of a crystalline phase (124), a self-healing glass (126), and gettering particles (122) in a matrix (128). Over the bond coat is a top coat (110), which may have porosity (112).

[0078] Figure 2 shows the mole fractions of the phases present in Example 2 of Table 1 above, illustrating the phase changes of the various components as the temperature increases. The slag contains primarily SiC, SiO2, ZrSiO4, and molten oxides.

[0079] FIG. 3 shows a viscosity graph of Example 2 of Table 1.

[0080] Figure 4 shows the mole fractions of the phases present in Example 2 from Table 2 above, illustrating the phase changes of the various components as the temperature increases. The slag contains primarily SiC, SiO2, ZrSiO4, mullite, and molten oxides.

[0081] FIG. 5 shows the viscosity graph of Example 2 of Table 2.

[0082] Drawing Description: Figure 1: 100-Coating System 110-Top Coat 112-porous 120-Bond Coat 122-gettering particles 124-crystalline phase 126-Self-healing glass 128-Bond Coat Matrix 130-CMC Figure 2: 200—Graph showing the phase diagram of particular embodiment 2 of Table 1 as a function of temperature 202-Ca2ZrSi4O 12 204-CaAl2Si2O8 206-Slug 208-SiO2 210-ZrSiO4 212-SiC Figure 3: 300—Graph showing viscosity as a function of temperature for slag (molten oxide) present in embodiment 2 of Table 1 302-Slug Figure 4: 400—Graph showing the phase makeup of Particular Embodiment 2 of Table 2 as a function of temperature.

[0083] 402-Al6Si2O 13 403-Mg2Al4Si5O 18 404-BaAl2Si2O8 406-Slug 408-SiO2 410-ZrSiO4 412-SiC Figure 5: 500—Graph showing viscosity as a function of temperature for slag (molten oxide) present in embodiment 2 of Table 1 502-Slug Example of preparation method: Bond coats can be produced using a slurry coating method. A suitable slurry can be prepared by mixing ingredients such as silicon carbide, hafnium silicate, barium-magnesium aluminosilicate, and silicon oxide powders in a carrier fluid such as water. The slurry can be mixed using a ball mill, and the resulting slurry can be sprayed onto the underlying substrate. The slurry can be dried at room temperature and cured at 200°C for 1 hour. The coating can then be sintered in air at 1500°C for 1 hour.

[0084] As will be appreciated by one skilled in the art, the embodiments described herein may be embodied as methods of use or preparation, articles of manufacture including components for use in various assemblies, or uses per se.

[0085] The descriptions of the embodiments set forth herein have been presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. The embodiments have been chosen and described to best explain the principles and practical applications of the invention and to enable others skilled in the art to understand the embodiments of the invention, together with various modifications suitable for the particular use intended.

[0086] Modifications and equivalents may be made to the disclosed features without departing from the spirit or scope of the invention. Accordingly, the embodiments described herein are intended to cover the modifications and variations disclosed above, including changes that lead to equivalents; i.e., modifications and equivalents may be made to the features within the scope of the claims without departing from the scope of the invention.

Claims

1. 1. An environmental barrier coating having a bond coat layer, the bond coat layer comprising: comprising an oxide matrix, The entire oxide matrix is i) an oxide gettering phase forming silicon oxide; ii) Amorphous or crystalline SiO ２ System phase and iii) a crystalline phase; and iv) an amorphous oxide phase, which is a self-repairing phase that softens or melts at a predetermined temperature that is lower than the melting temperature of the oxide matrix and has the ability to flow into cracks formed in the oxide matrix, is dispersed therein; the amorphous oxide phase comprises an alkaline earth aluminosilicate glass; The crystalline phase is Al ６ Si ２ O １３ , ZrSiO ４ , HfSiO ４ , Ca ２ ZrSi ４ O １２ , Ca ２ HfSi ４ O １２ , CaAl ２ Si ２ O ８ , CaSiO ３ , Al ２ TiO ５ , Mg ２ Al ４ Si ５ O １８ , BaAl ２ Si ２ O ８ , BaZrSi ３ O ９ , Y ２ Si ２ O ７ , Yb ２ Si ２ O ７ , and / or Al ２ O ３ and SiO in ii) ２ When the system phase is amorphous, the crystalline phase may be crystalline SiO in addition to the candidates mentioned above. ２ The environmental barrier coating further comprises:

2. 10. The environmental barrier coating of claim 1, wherein the amorphous oxide phase comprises a calcium aluminosilicate glass having an incipient melting point of 1150°C to 1300°C, a viscosity at 1300°C of 200 to 20,000 Pa s, and a viscosity at 1500°C of 1 to 500 Pa s, the calcium aluminosilicate glass optionally doped with one or more rare earth or transition metal elements.

3. The environmental barrier coating of claim 1 , wherein the amorphous oxide phase comprises a barium-magnesium aluminosilicate glass.

4. The environmental barrier coating comprises in the bond coat layer: The oxide matrix contains 1 to 25% by volume, i) the oxide gettering phase is 25 to 75% by volume; ii) the crystalline phase is 5 to 50 volumes; iii) The environmental barrier coating of claim 1, wherein the amorphous oxide phase is 1 to 10 volume percent.

5. The oxide matrix is ​​SiO ２ 2. The environmental barrier coating of claim 1, wherein:

6. The oxide gettering phase is Si ｘ O ｙ C ｚ (wherein 0.5≦x<1, 0≦y<2, 0≦z<2), or Si ３ N ４ or SiCN.

7. The environmental barrier coating of claim 1 , wherein the oxide gettering phase is SiC.

8. The bond coat layer comprises: 50% by volume of a SiC gettering phase; 25% by volume of ZrSiO ４ and, 20% by volume of SiO ２ a matrix phase; 5% by volume of a self-healing phase consisting of a calcium aluminosilicate glass having an incipient melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa s at 1260°C, and a viscosity of 10 to 500 Pa s at 1482°C.

9. The bond coat layer comprises: 50% by volume of a SiC gettering phase; 25% by volume of Ca ２ HfSi ４ O １２ and, 20% by volume of SiO ２ a matrix phase; 5% by volume of a self-healing phase consisting of a calcium aluminosilicate glass having an incipient melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa s at 1260°C, and a viscosity of 10 to 500 Pa s at 1482°C.

10. The bond coat layer comprises: 40 to 70 volume % of a SiC gettering phase; 10 to 30 volume % ZrSiO ４ and, 10 to 30% by volume of SiO ２ a matrix phase; 5-10 volume % of a self-healing phase consisting of a calcium aluminosilicate glass having an incipient melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa s at 1260°C, and a viscosity of 10 to 500 Pa s at 1482°C.

11. The bond coat layer comprises: 40 to 70 volume % of a SiC gettering phase; 5 to 50% by volume of ZrSiO ４ and, 5 to 20% by volume of SiO ２ a matrix phase; 1 to 10 volume percent of a self-healing phase consisting of a calcium aluminosilicate glass having an incipient melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa s at 1260°C, and a viscosity of 10 to 500 Pa s at 1482°C.

12. The bond coat layer comprises: 50% by volume of a SiC gettering phase; 25% by volume of Al ６ Si ２ O １３ and, 20% by volume of SiO ２ a matrix phase; 5% by volume of a self-healing phase consisting of a calcium aluminosilicate glass having an incipient melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa s at 1260°C, and a viscosity of 10 to 500 Pa s at 1482°C.

13. The bond coat layer comprises: 50% by volume of a SiC gettering phase; 20 to 25% by volume of Al ６ Si ２ O １３ and, 20 to 25% by volume of SiO ２ a matrix phase; 3-5 vol % of a self-healing phase consisting of a rare earth aluminosilicate glass having an incipient melting point of 1150°C to 1200°C, a viscosity of 1,000 to 50,000 Pa s at 1260°C, and a viscosity of 10 to 500 Pa s at 1482°C.

14. The bond coat layer comprises: 40 to 70 volume % of a SiC gettering phase; 5 to 50% by volume of ZrSiO ４ and, 5 to 20% by volume of SiO ２ a matrix phase; 1 to 10 volume percent of a self-healing phase consisting of an ytterbium aluminosilicate glass having an incipient melting point of 1350°C to 1500°C, a viscosity of 1,000 to 50,000 Pa s at 1260°C, and a viscosity of 10 to 500 Pa s at 1482°C.

15. The environmental barrier coating of claim 1 , wherein the oxide gettering phase, the crystalline phase, and / or the amorphous oxide phase are dispersed in the oxide matrix in the form of discrete particles.

16. A turbine vane or blade, or turbine engine component, comprising the environmental barrier coating of claim 1 on a surface thereof.

17. 1. An environmental barrier coating system on a silicon-containing material, the coating system including a bond coat layer and a protective top coat thereon, the bond coat layer comprising: comprising an oxide matrix, The entire oxide matrix is i) an oxide gettering phase forming silicon oxide; ii) Amorphous or crystalline SiO ２ System phase and iii) a crystalline phase; and iv) an amorphous oxide phase, which is a self-repairing phase that softens or melts at a predetermined temperature that is lower than the melting temperature of the oxide matrix and has the ability to flow into cracks formed in the oxide matrix, is dispersed therein; the amorphous oxide phase comprises an alkaline earth aluminosilicate glass; The crystalline phase is Al ６ Si ２ O １３ , ZrSiO ４ , HfSiO ４ , Ca ２ ZrSi ４ O １２ , Ca ２ HfSi ４ O １２ , CaAl ２ Si ２ O ８ , CaSiO ３ , Al ２ TiO ５ , Mg ２ Al ４ Si ５ O １８ , BaAl ２ Si ２ O ８ , BaZrSi ３ O ９ , Y ２ Si ２ O ７ , Yb ２ Si ２ O ７ , and / or Al ２ O ３ and SiO in ii) ２ When the system phase is amorphous, the crystalline phase may be crystalline SiO in addition to the candidates mentioned above. ２ The environmental barrier coating system further comprises:

18. 20. The environmental barrier coating system of claim 17, wherein the silicon-containing material is a ceramic matrix composite.

19. The top coat may be a binary or multi-component oxide, such as HfO ２ , ZrO ２ , Gd ２ Hf ２ O ７ , Gd ２ Zr ２ O ７ 20. The environmental barrier coating system of claim 17, comprising a refractory metal oxide, a silicate, a rare earth monosilicate or disilicate, an alkaline earth aluminosilicate, or a hafnium or zirconium silicate.

20. 1. A method of protecting a ceramic matrix composite material, comprising applying a bond coat layer and a top coat thereover, the bond coat layer comprising: comprising an oxide matrix, The entire oxide matrix is i) an oxide gettering phase forming silicon oxide; ii) Amorphous or crystalline SiO ２ System phase and iii) a crystalline phase; and iv) an amorphous oxide phase, which is a self-repairing phase that softens or melts at a predetermined temperature that is lower than the melting temperature of the oxide matrix and has the ability to flow into cracks formed in the oxide matrix, is dispersed therein; the amorphous oxide phase comprises an alkaline earth aluminosilicate glass; The crystalline phase is Al ６ Si ２ O １３ , ZrSiO ４ , HfSiO ４ , Ca ２ ZrSi ４ O １２ , Ca ２ HfSi ４ O １２ , CaAl ２ Si ２ O ８ , CaSiO ３ , Al ２ TiO ５ , Mg ２ Al ４ Si ５ O １８ , BaAl ２ Si ２ O ８ , BaZrSi ３ O ９ , Y ２ Si ２ O ７ , Yb ２ Si ２ O ７ , and / or Al ２ O ３ and SiO in ii) ２ When the system phase is amorphous, the crystalline phase may be crystalline SiO in addition to the candidates mentioned above. ２ The method further comprises:

Images