A thermally stable thermal barrier coating exhibiting improved thermal conductivity and corrosion resistance.

Abstract

A thermal spray material exhibiting improved thermal conductivity and solid particle erosion resistance is provided for a thermal barrier coating. The thermal spray material forms a thermally stable coating upon thermal spraying. The coating includes at least one phase exhibiting improved thermal conductivity and at least one phase exhibiting improved solid particle erosion resistance.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit and priority of U.S. Provisional Application No. 63 / 134,023, filed on January 5, 2021, the disclosure of which is hereby expressly incorporated herein by reference in its entirety.

[0002] Exemplary embodiments generally relate to thermal spray materials that form a thermally stable coating composition during thermal spraying. In an exemplary embodiment, the coating composition exhibits improved thermal conductivity and solid particle erosion resistance for thermal barrier coatings (TBCs). In particular, exemplary embodiments relate to a thermal spray material comprising at least one erosion - resistant component and at least one thermal - conductivity component, and methods of manufacturing and using the same.

Background Art

[0003] Thermal barrier coatings (TBCs) are used in a plurality of applications, including gas turbine engines, automotive industries, drilling applications in oil and gas industries, steel industries or agricultural applications. TBCs are applied to components such as combustors, high - pressure turbine blades, vanes, and shrouds. The application of TBCs can increase the operating temperature of high - temperature gas path components, resulting in higher energy output and improved engine efficiency. The insulation provided by TBCs allows the components coated by the TBCs to survive at higher operating temperatures, improving the durability of the components and the reliability of the engine. Significant advancements in high - temperature performance have been achieved, and typical yttria - stabilized zirconia (YSZ) can be used for insulation in TBC systems. Coatings with 7 - 8 wt% yttria added to zirconia provide thermal shock resistance due to their metastable transformation phase.

Summary of the Invention

Means for Solving the Problems

[0004] Exemplary embodiments of this disclosure relate to powders that form a thermal barrier coating during thermal spraying. In one embodiment, the powder is ceramic powder. Ceramic powder is advantageous due to its resistance to high temperatures exceeding 1000°C, but the generally higher hardness of this material can also lead to wear damage, for example, to nickel superalloy turbine blades (aerospace or gas turbine sections).

[0005] Severe wear damage can arise from inefficient cutting processes, leading to excessive frictional heating of the blade material under severe frictional contact conditions within the turbine and / or if the thermal-sprayed abrasive coating is too hard. Examples of damage mechanisms to the blade include bulk plastic deformation and fracture, oxidation of the material resulting from frictional heating, and cracking of the material due to extreme cutting forces.

[0006] Thermal barrier coatings (TBCs) can improve the thermal insulation and corrosion resistance properties of the coated components and maintain these properties over the service life of the components by reducing sintering caused by the use of ceramic powders. The thermal spray materials for TBCs of this disclosure differ from typical TBCs due to the multiphase nature of the coating.

[0007] In this disclosure, in the disclosed examples and claims, the term “phase” refers to the attributes of each component in the thermal spray material.

[0008] Exemplary embodiments of this disclosure relate to a thermal spray material comprising at least one erosion-resistant phase and at least one thermal conductivity phase. In embodiments, either the thermal conductivity phase or the erosion-resistant phase is a tetragonal phase. The erosion-resistant phase and the thermal conductivity phase have been found to be thermally stable, as demonstrated by being in substantially the same proportion after exposure to a high temperature of at least 1250°C for more than 300 hours. The erosion-resistant phase is in the range of 60–80% by weight and the thermal conductivity phase is in the range of 20–40% by weight after 300 hours of exposure to high temperature. Thus, the ratio of the erosion-resistant phase to the thermal conductivity phase is about 2:1. In preferred embodiments, after 300 hours of exposure to high temperature, the erosion-resistant phase is about 70% by weight and the thermal conductivity phase is about 30% by weight. Thus, the ratio of the erosion-resistant phase to the thermal conductivity phase is about 7:3. The multiphase structure of the components in the thermal barrier coating of this disclosure provides improved erosion and thermal conductivity properties compared to a typical TBC containing only one of these phases.

[0009] In exemplary embodiments, at least one erosion-resistant phase comprises partially stabilized zirconium oxide containing a primary stabilizer such as ytterbium oxide and / or dysprosium oxide. In embodiments, at least one erosion-resistant phase comprises ytterbium oxide-stabilized zirconium oxide containing 84-86% by weight of ZrO2 and 14-16% by weight of Yb2O3. In other embodiments, at least one erosion-resistant phase comprises ytterbium oxide-stabilized zirconium oxide containing 82-86% by weight of ZrO2 and 14-18% by weight of Yb2O3.

[0010] In one embodiment, the amount of primary stabilizer in the erosion-resistant phase is in the range of 0.1 to 6.0 mol%. In another embodiment, the amount of primary stabilizer in the erosion-resistant phase is in the range of 5.0 to 6.0 mol%.

[0011] In exemplary embodiments, at least one lower thermal conductivity phase comprises a portion containing a stabilizer oxide or fully stabilized zirconia (or zirconate). In embodiments, at least one lower thermal conductivity phase comprises cubic zirconium oxide containing 78-81 wt% ZrO2, 9-10 wt% Y2O3, 5-6 wt% Gd2O3, and 5-6 wt% Yb2O3. In other embodiments, at least one lower thermal conductivity phase comprises dysprosium oxide-stabilized zirconium oxide containing 88-92 wt% ZrO2 and 9-11 wt% Dy2O3.

[0012] In some embodiments, the stabilizer oxide may be one or more of the following oxides: yttrium, gadolinium, dysprosium, or ytterbium. In some embodiments, the total amount of stabilizer oxide in the thermal conductivity phase is in the range of 3 to 35 mol%. In other embodiments, the total amount of stabilizer oxide in the thermal conductivity phase is in the range of 3 to 10 mol%.

[0013] In non-limiting embodiments, the thermal spray material contains a highly erosion-resistant material at a concentration in the range of 50 to 90% by weight. In embodiments, the thermal spray material contains a highly erosion-resistant material at a concentration in the range of 60 to 80% by weight. In other embodiments, the thermal spray material contains a highly erosion-resistant material at a concentration in the range of 68 to 72% by weight. In preferred embodiments, the thermal spray material contains a highly erosion-resistant material at a concentration of about 70% by weight.

[0014] In non-limiting embodiments, at least one erosion-resistant phase and at least one low-thermal-conductivity phase are present in the thermally stable coating material as a composite, blend, or clad powder. In other embodiments, the blend or clad powder provides improved coating performance, particularly erosion resistance.

[0015] In non-limiting embodiments, a method for producing a thermally stable coating composition includes combining at least one erosion-resistant phase with at least one low thermal conductivity phase to obtain a thermal spray material as a composite, blend, or cladding. The thermal spray material is then plasma sprayed to obtain a thermally stable coating material.

[0016] In other embodiments, at least one corrosion-resistant phase and at least one low thermal conductivity phase are not alloyed together before plasma spraying. In embodiments, the method for producing the thermally stable coating composition offers the advantage of maintaining a coating with improved corrosion resistance.

[0017] The thermally stable coating material obtained in this disclosure provides lower thermal conductivity and equivalent or better solid particle erosion resistance compared to a typical yttria-stabilized zirconia (YSZ) coating having 7-8 wt% yttria added to zirconia having a similar coating microstructure. Furthermore, the thermally stable coating material obtained in this disclosure provides thermal stability such that the volume fraction of the phases present in the coating remains substantially the same after prolonged heat treatment / high-temperature exposure at least 1250°C.

[0018] This disclosure is further described below in detail with reference to the drawings shown, as non-limiting examples of preferred embodiments of this disclosure. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 shows multiphase coating layers applied to a substrate according to various embodiments. [Figure 2A] This is a scanning electron microscope (SEM) image showing a thermal spray material according to one embodiment of the present disclosure. [Figure 2B] This is a SEM image showing a sprayed coating applied by atmospheric pressure plasma spraying (APS) according to one embodiment of the present disclosure. [Figure 3A] This is an SEM image showing a thermal spray material according to one embodiment of the present disclosure. [Figure 3B] This is an SEM image showing the low-conductivity phase of a thermal spray coating applied by APS according to one embodiment of the present disclosure. [Figure 3C] This is an SEM image showing the corrosion-resistant phase of a thermal spray coating applied by APS according to one embodiment of the present disclosure.

Best Mode for Carrying Out the Invention

[0020] In FIG. 1, the multiphase coating layer 15 includes at least one erosion-resistant phase 110 and at least one thermal conductivity phase 120. The term "phase" refers to the attribute of each component in the spraying material before plasma spraying to obtain the multiphase coating layer 15. The multiphase coating layer 15 is applied on a substrate layer 10 (for example, metal or ceramic).

[0021] In one embodiment, the erosion-resistant phase 110 includes partially stabilized zirconia containing a primary stabilizer, such as ytterbium oxide and / or dysprosium oxide, in an amount in the range of 0.1 to 6.0 mol%.

[0022] In one embodiment, the low thermal conductivity phase 120 includes partially or fully stabilized zirconia (or zirconate) containing a stabilizer oxide including yttrium, gadolinium, dysprosium, and / or ytterbium. In an embodiment, the total amount of the stabilizer oxide in the thermal conductivity phase is in the range of 3 to 35 mol%.

[0023] The spraying material can be manufactured by blending or cladding at least one erosion-resistant phase 110 and at least one thermal conductivity phase 120. The multiphase coating layer 15 is formed by plasma spraying the spraying material on the substrate 10.

Examples

[0024] Example 1 A thermal spray material according to a preferred embodiment of the present disclosure was produced by blending a corrosion-resistant component (A) 210 with a thermally conductive component (B) 200. The microstructure of the resulting thermal spray material is shown in Figure 2A. The chemical composition of component (A) 210 was as follows: 93-96 mol% ZrO2 and 4-7 mol% Yb2O3 (or 82-86 wt% ZrO2 and 14-18 wt% Yb2O3). The chemical composition of component (B) 200 was as follows: 88-93 mol% ZrO2, 1-3 mol% Yb2O3, 5-6 mol% Y2O3, 1-3 mol% Gd2O3 (or 78-81 wt% ZrO2, 5-6 wt% Yb2O3, 9-10 wt% Y2O3, and 5-6 wt% Gd2O3).

[0025] Next, the spray material was sprayed using atmospheric pressure plasma spraying (APS) to obtain a thermally stable multiphase coating material. The microstructure of the resulting thermally stable multiphase coating material is shown in Figure 2B.

[0026] Figure 2B shows a SEM image of a thermally stable multiphase coating material containing at least two phases: (1) a thermal conductivity phase 230 and (2) an erosion-resistant phase 220. The thermal conductivity phase 230 constituted 30 wt% of the total thermally stable multiphase coating material. The chemical composition of the thermal conductivity phase 230 was cubic zirconium oxide containing 78–81 wt% ZrO2, 9–10 wt% Y2O3, 5–6 wt% Gd2O3, and 5–6 wt% Yb2O3.

[0027] The corrosion-resistant phase 220 constituted 70% by weight of the total thermally stable multiphase coating material. The chemical composition of the corrosion-resistant phase 220 consisted of ytterbium oxide-stabilized zirconium oxide containing 84–86% by weight of ZrO2 and 14–16% by weight of Yb2O3.

[0028] The chemical composition of the combination of both the thermally conductive phase 230 and the corrosion-resistant phase 220 was as follows: 91-94.5 mol% ZrO2, 4-5 mol% Yb2O3, 1-3 mol% Y2O3, and 0.5-1.0 mol% Gd2O3 (or 81-83 wt% ZrO2, 12-14 wt% Yb2O3, 2-4 wt% Y2O3, and 2-4 wt% Gd2O3).

[0029] The thermal conductivity of individual phases and combined phases was determined by comparing coatings with equivalent porosity. The results are shown in Table 1.

[0030] [Table 1]

[0031] The corrosion resistance of individual phases and combined phases was determined by comparing them with coatings having equivalent porosity. The results are shown in Table 2.

[0032] [Table 2]

[0033] Example 2 A thermal spray material according to another preferred embodiment of the present disclosure was produced by blending a corrosion-resistant component (A) 300 with a thermally conductive component (B) 310. The microstructure of the resulting thermal spray material is shown in Figure 3A. The chemical composition of component (A) 300 was as follows: 93-96 mol% ZrO2 and 4-7 mol% Yb2O3 (or 82-86 wt% ZrO2 and 14-18 wt% Yb2O3). The chemical composition of component (B) 310 was as follows: 95-98 mol% ZrO2 and 2-5 mol% Dy2O3 (or 88-92 wt% ZrO2 and 8-12 wt% Dy2O3).

[0034] Next, the thermal spray material was sprayed using APS to obtain a thermally stable multiphase coating material. The microstructure of the thermally conductive phase in the thermally stable multiphase coating material is shown in Figure 3B. Corrosion resistance in the thermally stable multiphase coating material phase The resulting microstructure is shown in Figure 3C.

[0035] Figure 3B shows an SEM image of the thermal conductivity phase in a thermally stable multiphase coating material containing 88–92 wt% ZrO2 and 9–11 wt% Dy2O3. The thermal conductivity phase accounted for 30 wt% of the total thermally stable multiphase coating material. The chemical composition of the thermal conductivity phase in the thermally stable multiphase coating material was dysprosium oxide-stabilized zirconium oxide containing 88–92 wt% ZrO2 and 9–11 wt% Dy2O3.

[0036] Figure 3C shows an SEM image of the corrosion-resistant phase in the thermally stable multiphase coating material. The corrosion-resistant phase accounted for 70% by weight of the total thermally stable multiphase coating material. The chemical composition of the corrosion-resistant phase in the thermally stable multiphase coating material was ytterbium oxide-stabilized zirconium oxide containing 82–86% by weight of ZrO2 and 14–18% by weight of Yb2O3.

[0037] The chemical composition of the combination of both the thermally conductive phase and the corrosion-resistant phase was as follows: 91-98 mol% ZrO2, 2-6 mol% Yb2O3 and 0.3-3 mol% Dy 2 O 3 (or 80-92% by weight of ZrO2, 7-14% by weight of Yb2O3, and 1-6% by weight of Dy2O3).

[0038] The thermal conductivity of individual phases and combined phases was determined by comparing coatings with equivalent porosity. The results are shown in Table 3.

[0039] [Table 3]

[0040] The corrosion resistance of individual phases and combined phases was determined by comparing them with coatings having equivalent porosity. The results are shown in Table 4.

[0041] [Table 4]

[0042] Furthermore, since the present invention is disclosed herein in a manner that enables the invention to be manufactured and used, for example for simplification or efficiency, by disclosing certain exemplary embodiments, the present invention can be carried out without the presence of any additional elements or structures not specifically disclosed herein.

[0043] It should be noted that the examples described herein are provided for illustrative purposes only and should not be construed as limiting the invention. While the invention has been described with reference to exemplary embodiments, it should be understood that the words used herein are descriptive and illustrative, not limiting. Modifications may be made within the scope of the appended claims, without departing from the scope and spirit of the invention in that aspect, as described and modified. While the invention has been described herein with reference to specific means, materials, and embodiments, the invention is not intended to be limited to the details disclosed herein. Rather, the invention extends to all functionally equivalent structures, methods, and uses, such as those within the scope of the appended claims.

Claims

1. A thermal spray powder material for heat-shielding coatings, Component (A) consisting of at least one erosion-resistant phase, A component (B) consisting of at least one thermally conductive phase, Includes, The chemical composition of the component (A) is 93 to 96 mol% of ZrO ２ and 4 to 7 mol% of Yb ２ O ３ and the chemical composition of the component (B) is 88 to 93 mol% of ZrO ２ , 1 to 3 mol% of Yb ２ O ３ , 5 to 6 mol% of Y ２ O ３ , and 1 to 3 mol% of Gd ２ O ３ and The thermal spray powder material contains component (A) in a concentration in the range of 50 to 90% by weight, and component (B) in a concentration in the range of 10 to 50% by weight. The aforementioned components (A) and (B) are both non-alloyed thermal spray powder materials.

2. A thermal spray powder material for heat-shielding coatings, Component (A) consisting of at least one erosion-resistant phase, A component (B) consisting of at least one thermally conductive phase, Includes, The chemical composition of component (A) is 93-96 mol% ZrO ２ and 4-7 mol% Yb ２ O ３ The chemical composition of component (B) is 95-98 mol% ZrO ２ and 2-5 mol% Dy ２ O ３ And, The thermal spray powder material contains component (A) in a concentration in the range of 50 to 90% by weight, and component (B) in a concentration in the range of 10 to 50% by weight. The aforementioned components (A) and (B) are both non-alloyed thermal spray powder materials.

3. A method for manufacturing a thermally stable multiphase coating material for heat-shielding coatings, A step of obtaining a thermal spray powder material by blending a component (A) consisting of at least one erosion-resistant phase and a component (B) consisting of at least one thermal conductivity phase, The step of plasma spraying the thermal spray powder material to obtain the thermally stable multiphase coating material comprising at least one corrosion-resistant phase and at least one thermally conductive phase. Includes, The chemical composition of component (A) is 93-96 mol% ZrO ２ and 4-7 mol% Yb ２ O ３ The chemical composition of component (B) is 88-93 mol% ZrO ２ , 1-3 mol% Yb ２ O ３ , 5-6 mol% Y ２ O ３ , and 1-3 mol% Gd ２ O ３ And, The thermal spray powder material contains component (A) in a concentration in the range of 50 to 90% by weight, and component (B) in a concentration in the range of 10 to 50% by weight. A method wherein component (A) and component (B) are not alloyed before plasma spraying.

4. A method for manufacturing a thermally stable multiphase coating material for heat-shielding coatings, A step of obtaining a thermal spray powder material by blending a component (A) consisting of at least one erosion-resistant phase and a component (B) consisting of at least one thermal conductivity phase, The step of plasma spraying the thermal spray powder material to obtain the thermally stable multiphase coating material comprising at least one corrosion-resistant phase and at least one thermally conductive phase. Includes, The chemical composition of component (A) is 93-96 mol% ZrO ２ and 4-7 mol% Yb ２ O ３ The chemical composition of component (B) is 95-98 mol% ZrO ２ and 2-5 mol% Dy ２ O ３ And, The thermal spray powder material contains component (A) in a concentration in the range of 50 to 90% by weight, and component (B) in a concentration in the range of 10 to 50% by weight. A method wherein component (A) and component (B) are not alloyed before plasma spraying.

5. At least one erosion-resistant phase, At least one thermally conductive phase, A thermally stable multiphase coating material obtained from the thermal spray powder material according to claim 1 or 2, comprising:

6. The thermally stable multiphase coating material according to claim 5, wherein the at least one corrosion-resistant phase is in the range of 50 to 90% by weight of the thermally stable multiphase coating material, and the at least one thermally conductive phase is in the range of 10 to 50% by weight of the thermally stable multiphase coating material.

7. The thermally stable multiphase coating material according to claim 6, wherein the at least one corrosion-resistant phase is in the range of 60 to 80% by weight of the thermally stable multiphase coating material, and the at least one thermally conductive phase is in the range of 20 to 40% by weight of the thermally stable multiphase coating material.

8. The thermally stable multiphase coating material according to claim 6, wherein the at least one corrosion-resistant phase is in the range of 65 to 75% by weight of the thermally stable multiphase coating material, and the at least one thermally conductive phase is in the range of 25 to 35% by weight of the thermally stable multiphase coating material.

9. The at least one corrosion-resistant phase is 84-86% by weight of ZrO ２ and 14-16% by weight of Yb ２ O ３ The ytterbium oxide-stabilized zirconium oxide contains the following, and the at least one thermally conductive phase is 78-81% by weight of ZrO ２ , 9-10% by weight of Y ２ O ３ , 5-6% by weight of Gd ２ O ３ and 5-6% by weight of Yb ２ O ３ A thermally stable multiphase coating material according to claim 5, comprising cubic zirconium oxide.

10. The at least one corrosion-resistant phase is 82-86% by weight of ZrO ２ and 14-18% by weight of Yb ２ O ３ The ytterbium oxide-stabilized zirconium oxide contains the following, wherein the at least one thermally conductive phase is 88-92% by weight of ZrO ２ and 9-11% by weight of Dy ２ O ３ The thermally stable multiphase coating material according to claim 5, comprising dysprosium oxide-stabilized zirconium oxide.

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