Powder for examining environmental barrier coating and preparation method thereof

Abstract

The invention provides powder for examining an environmental barrier coating and a preparation method of the powder, and relates to the field of materials. The method comprises the following steps: dissolving calcium oxide, magnesium oxide, aluminum oxide and silicon oxide by using an acid solution, and precipitating the obtained solute by using an alkali solution to obtain a suspension; performing spray gun spheroidization on the suspension to obtain amorphous powder for examining the environmental barrier coating; the power of the spray gun for spray gun spheroidizing is 50-60 Kw; the powder feeding speed is 60 g / min to 120 g / min; and the carrier gas flow is 3.5 L / min to 4.5 L / min. Amorphous powder can be rapidly prepared through a suspension spray gun spheroidizing method, and the method is suitable for being applied to assessment of environmental barrier coatings.

Description

Technical Field

[0001] The present application relates to the field of materials, and in particular to a powder for evaluating environmental barrier coatings and a preparation method thereof. Background Art

[0002] CMAS is a mixture of CaO-MgO-Al2O3-SiO2. CMAS corrosion simulates airborne particles such as sand, debris, and volcanic ash to study the effects of these particles' melt deposits on the failure mechanisms of engine hot-end components at high temperatures. Currently, the most common CMAS production technology is solid-phase synthesis, which involves mixing oxides, sintering them, and then crushing them into small particles. This produces CMAS powder with uneven composition and irregular shape, and low strength, failing to accurately simulate the melt deposits of particles. Furthermore, the solid-phase synthesis process is lengthy and complex, making it unsuitable for large-scale application in many operating conditions. Summary of the Invention

[0003] The purpose of this application is to provide a powder for evaluating environmental barrier coatings and a preparation method thereof to solve the above problems.

[0004] To achieve the above objectives, the first aspect of the present application provides a method for preparing a powder for evaluating an environmental barrier coating, comprising: Dissolving calcium oxide, magnesium oxide, aluminum oxide, and silicon oxide with an acid solution, and precipitating the resulting dissolved matter with an alkaline solution to obtain a suspension; Spheroidizing the suspension with a spray gun to obtain an amorphous powder for evaluating an environmental barrier coating; The spray gun power of the spray gun spheroidization is 50kW-60Kw; the powder feeding rate is 60g / min-120g / min; and the carrier gas flow rate is 3.5L / min-4.5L / min.

[0005] Optionally, the molar ratio of the calcium oxide, the magnesium oxide, the aluminum oxide and the silicon oxide is 30-35:8-15:6-9:30-50.

[0006] Optionally, the method for preparing powder for evaluating environmental barrier coatings satisfies at least one of the following conditions: A. The acid solution includes hydrochloric acid; B. The alkaline solution includes aqueous ammonia.

[0007] Optionally, the method for preparing powder for evaluating environmental barrier coatings satisfies at least one of the following conditions: A. The concentration of the hydrochloric acid is 36%-38%; B. The concentration of the ammonia water is 25%-28%.

[0008] Optionally, the method for preparing powder for evaluating environmental barrier coatings satisfies at least one of the following conditions: A. The pH value of the dissolved substance is 3-4; B. The pH value of the suspension is 8-10.

[0009] Optionally, the temperature of the spray gun spheroidization is 1400°C-1500°C.

[0010] A second aspect of the present application provides a powder for evaluating an environmental barrier coating, which is prepared by the method for preparing a powder for evaluating an environmental barrier coating.

[0011] Optionally, the powder used to evaluate the environmental barrier coating has a sphericity greater than 90%, a fluidity less than 30s / 50, and a particle strength greater than 150 MPa.

[0012] Optionally, the shape of the powder used to evaluate the environmental barrier coating includes spherical and / or quasi-spherical shapes.

[0013] Optionally, the diameter of the powder used to evaluate the environmental barrier coating is 15 μm-75 μm.

[0014] Compared with the prior art, the advantages of this application include: The method for preparing powder for evaluating environmental barrier coatings provided in this application can quickly prepare amorphous powder by using a suspension spray gun spheroidization method, which is suitable for evaluating environmental barrier coating applications.

[0015] The powder provided in this application for evaluating environmental barrier coatings has uniform composition, regular shape and high strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0017] Figure 1 This is the SEM image of the powder prepared in Example 1 for evaluating the environmental barrier coating. DETAILED DESCRIPTION

[0018] As used herein: "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0019] The conjunction "consisting of" excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim, rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0020] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed alone. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including the range "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0021] In these examples, parts and percentages are by mass unless otherwise indicated.

[0022] "Parts by mass" refers to the basic unit of measurement used to express the mass ratio of multiple components. One part can represent any unit of mass, such as 1g or 2.689g. For example, if we say that the parts by mass of component A are a parts and the parts by mass of component B are b parts, this means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, we could say that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number representing a multiplication factor). It's important to note that, unlike parts by mass, the sum of the parts by mass of all components is not limited to 100 parts.

[0023] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0024] In a first aspect, the present application provides a method for preparing a powder for evaluating an environmental barrier coating, comprising: Dissolving calcium oxide, magnesium oxide, aluminum oxide, and silicon oxide with an acid solution, and precipitating the resulting dissolved matter with an alkaline solution to obtain a suspension; Spheroidizing the suspension with a spray gun to obtain an amorphous powder for evaluating an environmental barrier coating; The spray gun power of the spray gun spheroidization is 50kW-60kW; the powder feeding rate is 60g / min-120g / min; and the carrier gas flow rate is 3.5L / min-4.5L / min.

[0025] Optionally, the spray gun power of the spray gun spheroidization can be 50kW, 51kW, 52kW, 53kW, 54kW, 55kW, 56kW, 57kW, 58kW, 59kW, 60kW or any value between 50kW and 60kW, the powder feeding rate can be 60g / min, 70g / min, 80g / min, 90g / min, 100g / min, 110g / min, 120g / min or any value between 60g / min and 120g / min, and the carrier gas flow rate can be 3.5L / min, 3.6L / min, 3.7L / min, 3.8L / min, 3.9L / min, 4L / min, 4.1L / min, 4.2L / min, 4.3L / min, 4.4L / min, 4.5L / min or any value between 3.5L / min and 4.5L / min.

[0026] It should be noted that when the spray gun power is too high, the powder phase structure will change to a crystalline state. When the spray gun power is too low, the spheroidization effect will not be achieved, and the output powder will be irregular in shape. When the powder feeding rate is too slow, the powder phase structure will change to a crystalline state. When the powder feeding rate is too fast, the spheroidization effect will not be achieved, and the output powder will be irregular in shape. When the carrier gas flow rate is too fast, the spheroidization effect will not be achieved, and the output powder will be irregular in shape. When the carrier gas flow rate is too slow, the powder cannot be carried away, and the powder cannot reach the spheroidization cavity.

[0027] In some embodiments, the molar ratio of the calcium oxide, the magnesium oxide, the aluminum oxide, and the silicon oxide is 30-35:8-15:6-9:30-50.

[0028] Optionally, the molar ratio of calcium oxide, magnesium oxide, aluminum oxide and silicon oxide can be 30:8:6:30, 31:8:6:30, 32:8:6:30, 33:8:6:30, 34:8:6:30, 35:8:6:30, 30:9:6:30, 30:10:6:30, 30:11:6:30, 30:12:6:30, 3 0:13:6:30, 30:14:6:30, 30:15:6:30, 30:8:7:30, 30:8:8:30, 30:8:9:30, 30:8:6:35, 30:8:6:40, 30:8:6:45, 30:8:6:50 or any value between 30-35:8-15:6-9:30-50.

[0029] It should be noted that when the molar ratio of calcium oxide, magnesium oxide, aluminum oxide and silicon oxide meets 30-35:8-15:6-9:30-50, it can better simulate the environmental conditions in which aircraft engines may be corroded during service.

[0030] In some embodiments, the method for preparing a powder for evaluating an environmental barrier coating satisfies at least one of the following conditions: A. The acid solution includes hydrochloric acid; B. The alkaline solution includes aqueous ammonia.

[0031] In some embodiments, the method for preparing a powder for evaluating an environmental barrier coating satisfies at least one of the following conditions: A. The concentration of the hydrochloric acid is 36%-38%; Optionally, the concentration of hydrochloric acid may be 36%, 37%, 38%, or any value between 36% and 38%; B. The concentration of the ammonia water is 25%-28%.

[0032] Optionally, the concentration of the ammonia solution may be 25%, 26%, 27%, 28%, or any value between 25% and 28%.

[0033] In some embodiments, the method for preparing a powder for evaluating an environmental barrier coating satisfies at least one of the following conditions: A. The pH value of the dissolved substance is 3-4; Optionally, the pH value of the solute may be 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, or any value between 3 and 4; It should be noted that when the pH value of the solute is 3-4, the oxides will all be in a dissolved state, with no undissolved powder precipitating or suspended or floating in the container; B. The pH value of the suspension is 8-10.

[0034] Optionally, the pH value of the suspension can be 8, 8.5, 9, 9.5, 10 or any value between 8 and 10.

[0035] It should be noted that when the pH value of the suspension is 8-10, the precipitation is complete and no more excess precipitate will be produced if ammonia water is added further.

[0036] In some embodiments, the temperature of the spray gun spheroidization is 1400°C-1500°C.

[0037] Optionally, the temperature of the spray gun spheroidization can be 1400°C, 1410°C, 1420°C, 1430°C, 1440°C, 1450°C, 1460°C, 1470°C, 1480°C, 1490°C, 1500°C or any value between 1400°C and 1500°C.

[0038] It should be noted that the temperature of the spray gun spheroidization is controlled by the spray gun power. When the temperature of the spray gun spheroidization is 1400° C.-1500° C., the powder is in an amorphous spherical and / or quasi-spherical shape.

[0039] A second aspect of the present application provides a powder for evaluating an environmental barrier coating, which is prepared by the method for preparing a powder for evaluating an environmental barrier coating.

[0040] In some embodiments, the powder used to evaluate the environmental barrier coating has a sphericity greater than 90%, a fluidity less than 30s / 50, and a particle strength greater than 150 MPa.

[0041] Optionally, the sphericity of the powder used to evaluate the environmental barrier coating can be 90.1%, 90.5%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or any value greater than 90%, the fluidity can be 29s / 50, 25s / 50, 20s / 50, 15s / 50, 10s / 50, 5s / 50 or any value less than 30s / 50, and the particle strength can be 155MPa, 160MPa, 170MPa, 180MPa, 190MPa, 200MPa or any value greater than 150MPa.

[0042] In some embodiments, the powder used to evaluate the environmental barrier coating has a spherical and / or spherical-like shape.

[0043] In some embodiments, the diameter of the powder used to evaluate the environmental barrier coating is 15 μm-75 μm.

[0044] Optionally, the diameter of the powder used to evaluate the environmental barrier coating can be 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm or any value between 15μm and 75μm.

[0045] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.

[0046] It should be noted that since the influence of multiple process parameters such as spray gun power, powder feeding rate, carrier gas flow rate, etc. on the powder used to evaluate the environmental barrier coating is complex, it is necessary to first determine the appropriate process parameters. The specific experiment is as follows.

[0047] Analysis of spray gun power experiment: Calcium oxide, magnesium oxide, aluminum oxide, and silicon oxide are dissolved in 37% hydrochloric acid to obtain a dissolve having a pH of 3, wherein the molar ratio of calcium oxide, magnesium oxide, aluminum oxide, and silicon oxide is 32:10:8:50; The dissolved matter was then precipitated with aqueous ammonia to obtain a suspension with a pH of 9; The suspension was spheroidized by spray gun, and the spray gun power for spray gun spheroidization was set to 10kW, 20kW, 30kW, 40kW, 45kW, 50kW, 55kW, 50kW, 60kW, 65kW, 70kW, 80kW, and 90kW for multiple groups of experiments, and corresponding powder materials for evaluating environmental barrier coatings were obtained, among which the powder feeding rate was 80g / min; the carrier gas was hydrogen and argon in a mass ratio of 1:4, and the carrier gas flow rate was 4L / min.

[0048] Among them, the spray gun power controls the temperature of the spray gun spheroidization. The product performances of the above-mentioned powder materials used to evaluate the environmental barrier coating are shown in Table 1.

[0049] Among them, the atomic arrangement state is crystalline or amorphous and is tested using field scanning electron microscopy; The sphericity of powder is tested according to standard JY / T010; The fluidity test is carried out according to the standard GB / T1482; Particle strength is tested according to GB / T 43091.

[0050] Table 1 Spray gun power experimental data

[0051] Analysis: The spray gun power directly affects the temperature of the spray gun. As the power increases, the sphericity of the powder gradually increases and the fluidity becomes better and better. When the power is greater than 50kW, the sphericity, fluidity, particle strength and particle size meet the index requirements. When the power is greater than 60kW, the powder changes from amorphous to crystalline, and the powder properties change, which does not meet the requirements.

[0052] As shown in Table 1, the powders prepared in the 50kW-60kW range for evaluating environmental barrier coatings have better performance. This is because within this power range, the spray gun temperature is 1400-1500°C, at which time the powders are still amorphous, and the sphericity, fluidity, and particle size meet the index requirements.

[0053] Powder feeding rate experimental analysis: Calcium oxide, magnesium oxide, aluminum oxide, and silicon oxide are dissolved in 37% hydrochloric acid to obtain a dissolve having a pH of 4, wherein the molar ratio of calcium oxide, magnesium oxide, aluminum oxide, and silicon oxide is 35:15:9:41; The dissolved matter was then precipitated with aqueous ammonia to obtain a suspension with a pH of 10; The suspension was spheroidized by a spray gun, and the powder feeding rates of the spray gun spheroidization were set to 10g / min, 20g / min, 30g / min, 40g / min, 50g / min, 60g / min, 70g / min, 80g / min, 90g / min, 100g / min, 110g / min, 120g / min, 130g / min, 140g / min, and 150g / min respectively. Multiple groups of experiments were carried out, and corresponding powder materials for evaluating environmental barrier coatings were obtained. Among them, the spray gun power was 55kW, the carrier gas was hydrogen and argon in a mass ratio of 1:4, and the carrier gas flow rate was 4.5L / min.

[0054] The product properties of the above-mentioned powder materials used to evaluate environmental barrier coatings are shown in Table 2.

[0055] Table 2 Powder feeding rate experimental data

[0056] Analysis: The powder feeding rate affects the sphericity and particle size of the particles. If the powder feeding rate is too low, the sphericity of the particles decreases, the particles stick together, and the particle size increases. If the particle size is too large, the particle strength cannot be detected. As the powder feeding rate increases, the particle sphericity increases, the fluidity decreases, and the particle size decreases. When the powder feeding rate is greater than 120, the powder disperses, the sphericity decreases, the particle strength decreases, and the particle size decreases.

[0057] As shown in Table 1, the powder prepared in the range of 60 g / min-120 g / min for evaluating the environmental barrier coating has better performance. This is because the powder is still amorphous within this range, and the sphericity, fluidity and particle size meet the index requirements.

[0058] Carrier gas flow rate experimental analysis: Calcium oxide, magnesium oxide, aluminum oxide, and silicon oxide are dissolved in 37% hydrochloric acid to obtain a dissolve having a pH of 3, wherein the molar ratio of calcium oxide, magnesium oxide, aluminum oxide, and silicon oxide is 30:12:8:50; The dissolved matter was then precipitated with aqueous ammonia to obtain a suspension with a pH of 8; The suspension was spheroidized by a spray gun. The carrier gas for spray gun spheroidization was hydrogen and argon in a mass ratio of 1:4. The carrier gas flow rates were set to 1L / min, 1.5L / min, 2L / min, 2.5L / min, 3L / min, 3.5L / min, 4L / min, 4.5L / min, and 5L / min, respectively. Multiple groups of experiments were carried out, and corresponding powder materials for evaluating environmental barrier coatings were obtained. Among them, the spray gun power was 50Kw and the powder feeding rate was 60g / min.

[0059] The product properties of the above-mentioned powder materials used to evaluate environmental barrier coatings are shown in Table 3.

[0060] Table 3 Carrier gas flow experimental data

[0061] Analysis: When the carrier gas flow rate is too small, the powder particles agglomerate and stick together and cannot be separated. At this time, the particles have no fluidity. As the carrier gas increases, the agglomerated particles gradually disperse, the powder diameter decreases, the sphericity increases, and the fluidity increases. When the carrier gas flow rate is greater than 4.5L / min, the carrier gas flow rate is too large, the powder does not have time to spheroidize and directly rushes out of the cavity, the sphericity decreases, and the particle strength and fluidity decrease.

[0062] As shown in Table 1, the powder prepared in the range of 3.5L / min-4.5L / min for evaluating the environmental barrier coating has better performance. This is because the powder is spheroidized under the drive of the carrier gas, and the powder is evenly dispersed into spherical particles with good sphericity and fluidity. At this time, the powder particle strength meets the index requirements.

[0063] It can be seen from the above experiments that the influence of spray gun power, powder feeding rate and carrier gas flow rate on the performance of the environmental barrier coating finally used for evaluation is complex. After the above experimental tests, it was finally determined that when the spray gun power is 50kW-60kW; the powder feeding rate is 60g / min-120g / min; and the carrier gas flow rate is 3.5L / min-4.5L / min, the prepared amorphous powder of the environmental barrier coating for evaluation has uniform composition, regular shape and high strength.

[0064] Example 1 This embodiment provides a method for preparing powder for evaluating an environmental barrier coating, the specific steps comprising: S1: dissolving calcium oxide, magnesium oxide, aluminum oxide, and silicon oxide using 37% hydrochloric acid to obtain a dissolve having a pH of 3, wherein the molar ratio of calcium oxide, magnesium oxide, aluminum oxide, and silicon oxide is 30:8:6:30; S2: The dissolved matter is precipitated with aqueous ammonia to obtain a suspension with a pH of 8; S3: The suspension is sprayed with a spheroidizing gun at a power of 55 kW, a temperature of 1450°C, and a powder feeding rate of 80 g / min. The carrier gas is hydrogen and argon in a mass ratio of 1:4, and the carrier gas flow rate is 4.0 L / min. An amorphous powder for evaluating the environmental barrier coating is obtained. Among them, the SEM of powder used to evaluate environmental barrier coating is as follows: Figure 1 shown.

[0065] Example 2 The difference from Example 1 is that a dissolved substance with a pH value of 4 is obtained.

[0066] Example 3 The difference from Example 1 is that a suspension with a pH value of 10 is obtained.

[0067] Example 4 The difference from Example 1 is that the molar ratio of calcium oxide, magnesium oxide, aluminum oxide and silicon oxide in this example is 35:15:9:50.

[0068] The powder prepared in the above example was subjected to product testing, and the specific data are shown in Table 4.

[0069] Table 4 Product Test

[0070] analyze: The method for preparing powders for environmental barrier coating evaluation, provided herein, allows for rapid production of amorphous powders through suspension spray gun spheroidization, suitable for environmental barrier coating applications. When the spray gun is operated at 50kW-60kW and a temperature of 1400°C-1500°C, the crystal structure is amorphous, and indicators such as sphericity, flowability, particle strength, and powder diameter meet the requirements.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

[0072] Furthermore, those skilled in the art will appreciate that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and to form distinct embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is intended solely to enhance understanding of the overall background of this application and should not be construed as an admission or any implication that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for preparing powder for evaluating environmental barrier coatings, characterized in that: include: Dissolving calcium oxide, magnesium oxide, aluminum oxide, and silicon oxide with an acid solution, and precipitating the resulting dissolved matter with an alkaline solution to obtain a suspension; Spheroidizing the suspension with a spray gun to obtain an amorphous powder for evaluating an environmental barrier coating; The spray gun power of the spray gun spheroidization is 50kW-60Kw; the powder feeding rate is 60g / min-120g / min; and the carrier gas flow rate is 3.5L / min-4.5L / min.

2. The method for preparing powder for evaluating environmental barrier coating according to claim 1, characterized in that: The molar ratio of the calcium oxide, the magnesium oxide, the aluminum oxide and the silicon oxide is 30-35:8-15:6-9:30-50.

3. The method for preparing powder for evaluating environmental barrier coating according to claim 1, characterized in that: At least one of the following conditions is met: A. The acid solution includes hydrochloric acid; B. The alkaline solution includes aqueous ammonia.

4. The method for preparing powder for evaluating environmental barrier coating according to claim 3, characterized in that: At least one of the following conditions is met: A. The concentration of the hydrochloric acid is 36%-38%; B. The concentration of the ammonia water is 25%-28%.

5. The method for preparing powder for evaluating environmental barrier coating according to claim 1, characterized in that: At least one of the following conditions is met: A. The pH value of the dissolved substance is 3-4; B. The pH value of the suspension is 8-10.

6. The method for preparing a powder for evaluating an environmental barrier coating according to any one of claims 1 to 5, characterized in that: The temperature of the spray gun spheroidization is 1400°C-1500°C.

7. A powder for evaluating environmental barrier coatings, characterized in that: The powder is prepared by the method for preparing a powder for evaluating an environmental barrier coating according to any one of claims 1 to 6.

8. The powder for evaluating environmental barrier coating according to claim 7, characterized in that: The powder used for evaluating the environmental barrier coating has a sphericity greater than 90%, a fluidity less than 30s / 50, and a particle strength greater than 150MPa.

9. The method for preparing powder for evaluating environmental barrier coating according to claim 8, characterized in that: The shape of the powder used to evaluate the environmental barrier coating includes spherical and / or quasi-spherical shapes.

10. The method for preparing a powder for evaluating an environmental barrier coating according to any one of claims 7 to 9, characterized in that: The diameter of the powder used to evaluate the environmental barrier coating is 15 μm-75 μm.

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