CN111996484B

CN111996484B - A kind of nickel-based superalloy surface AlCrSi slurry infiltration agent and preparation method thereof

Info

Publication number: CN111996484B
Application number: CN202010856849.4A
Authority: CN
Inventors: 李瑞迪; 王悦婷; 袁铁锤; 邹亮
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2020-08-24
Filing date: 2020-08-24
Publication date: 2021-10-08
Anticipated expiration: 2040-08-24
Also published as: CN111996484A

Abstract

The invention discloses an AlCrSi slurry infiltration agent on the surface of nickel-based superalloy and a preparation method thereof. The raw materials include three components according to mass percentage, 18-30% of liquid component A and 35-60% of liquid component Part B, the balance is solid component C. The aluminizing slurry of the invention has reasonable compatibility, moderate aluminum content and various addition forms, which not only improves the infiltration speed of aluminum and the thickness of the infiltrated layer, but also ensures the toughness of the infiltrated layer and improves the mechanical properties. The activators and adhesives used all participate in or promote the reaction during the high-temperature aluminizing process, without harmful residues, ensuring the purity of the infiltrating layer and improving the service life of the aluminized coating. The aluminum-chromium-silicon slurry prepared by the invention greatly improves the sulfur corrosion resistance, oxygen corrosion resistance, thermal stability and coating life of the aluminum-chromium-silicon coating; meanwhile, the thickness of the coating prepared by the traditional aluminizing agent is improved. Defects such as unevenness, surface nodules, and local aluminum richness.

Description

AlCrSi slurry permeating agent on surface of nickel-based superalloy and preparation method thereof

Technical Field

The invention belongs to the technical field of metal material surface treatment, and particularly relates to an AlCrSi slurry permeating agent for a nickel-based superalloy surface and a preparation method thereof.

Background

The updating of the aerospace field requires more advanced and high thrust-weight turbine engines, and therefore also increasingly higher requirements are placed on the materials. The demand for aircraft engines is closely linked to the development of high temperature alloys. At present, the temperature of a gas inlet of an advanced gas turbine can reach 1600 ℃, the working temperature of a blade can reach 1000-1200 ℃, and a high-temperature part of a turbine engine is not only required to bear thermal cycle and mechanical load, but also required to be corroded by corrosive particles such as sulfate generated by fuel oil combustion. The nickel-based high-temperature alloy has good high-temperature oxidation resistance and hot corrosion resistance, and also has high-temperature creep strength and rupture strength, so that the nickel-based high-temperature alloy is widely applied to the fields of turbine engine blades and the like. The research trend of the current blade materials is to reduce the chromium content in the alloy to improve the high-temperature strength of the alloy, and the side effect is that the alloy generates more serious problems of high-temperature oxidation and gas hot corrosion when in use. Designs that rely solely on superalloy compositions have not been able to meet industry needs. Therefore, surface treatment techniques must be used to improve the performance of the superalloy to achieve higher operating temperatures. Therefore, it is necessary to find a protective coating with excellent high temperature oxidation resistance and high temperature corrosion resistance. Among the high performance aluminized coatings, the liquid (slurry) aluminizing process and the solid aluminizing process are the most mature and widely used processes. In a high-temperature oxidation environment, a compact alumina film is generated on the surface of the material by the aluminized coating, so that an external corrosion medium is prevented from further reacting with the matrix, and the matrix is effectively protected from external corrosion. However, the solid penetrating agent is easy to cause environmental pollution, the uniformity of a penetrating layer is difficult to control, nodules are easy to generate, local aluminum enrichment and the like, the liquid slurry is the best choice, and local aluminizing can be realized, but the aluminizing slurry of the traditional formula has the following problems: (1) the coating prepared by the traditional AlNi slurry permeating agent has insufficient high-temperature oxidation resistance and corrosion resistance; (2) the viscosity and the pH value of the traditional slurry are not appropriate, and the problems of local unevenness, tumor saving and the like appear after the surfaces of parts such as high-temperature alloy blades and the like are dried.

Disclosure of Invention

The invention aims to provide an AlCrSi slurry penetrant on the surface of a nickel-based high-temperature alloy, which is resistant to corrosion in an oxygen and sulfur atmosphere and uniform in coating property, and a preparation method thereof.

The AlCrSi slurry permeating agent for the surface of the nickel-based superalloy, disclosed by the invention, comprises 3 components, 18-30% of a liquid component A, 35-60% of a liquid component B and the balance of a solid component C in percentage by mass; wherein:

the liquid component A comprises the following raw materials in percentage by mass: 5-20% of AlCl₃3.7 to 8.6 percent of NH₄Cl and 8-15% of Cr₂O₃And 16-30% of H₃PO₄Solution, and the balance of absolute ethyl alcohol;

the liquid component B comprises the following raw materials in percentage by mass: 10-17.5% CrCl₃25 to 35% of Al₂O₃And 10-20% of H₃PO₄Solution, and the balance of absolute ethyl alcohol;

the solid component C is solid powder, and the raw materials comprise, by mass, 50-70% of spherical AlCr powder, 30-50% of Si powder, and the balance of spherical Al powder.

H in the components A and B₃PO₄The concentration of the solution is 80-90%; the liquid component A needs to be added with proper amount of water to adjust the density to be 1.1-1.5 g/cm³A pH of 0.2 to 1.2 and a viscosity of 3 to 15X 10^-3Pas; the liquid component B needs to be added with proper amount of water to adjust the density to be 1.0-1.4 g/cm³A pH of 0.8 to 2.6 and a viscosity of 5 to 12X 10^-3Pas; the content of Al in AlCr powder in the component C is 55-70%.

Preferably, the AlCrSi slurry seeping agent for the nickel-based superalloy surface comprises the following raw materials, by mass, 20% of a liquid component A, 40% of a liquid component B, and the balance of a solid component C.

Preferably, the liquid component A consists of the following components in percentage by mass: 6% AlCl₃6% NH₄Cl, 10% Cr₂O₃And 24% of H₃PO₄The balance of absolute ethyl alcohol.

Preferably, the liquid component B consists of the following components in percentage by mass: 15% CrCl₃30% of Al₂O₃And 15% of H₃PO₄The balance of absolute ethyl alcohol.

Preferably, the solid component C comprises the following components in percentage by mass: 60% of spherical AlCr powder, 30% of Si powder and the balance of spherical Al powder, wherein the content of Al in the AlCr powder is 60%.

The preparation method of the AlCrSi slurry permeating agent on the surface of the nickel-based superalloy comprises the following steps:

1) preparation of liquid component A: mixing AlCl₃、NH₄Cl、Cr₂O₃、H₃PO₄The solution and absolute ethyl alcohol are mixed according to the proportion. Then adding a proper amount of water, stirring and uniformly mixing, and adjusting the concentration of the diluted chlorine element to be lower than 10^-3mol/L, and adjusting the density, pH and viscosity of the components to the required range; then standing and filtering to obtain a liquid component A;

2) preparation of liquid component B: adding CrCl₃、Al₂O₃、H₃PO₄Mixing the solution and absolute ethyl alcohol according to a proportion, stirring and uniformly mixing, and then standing; then adding a proper amount of water, and adjusting the density, pH and viscosity of the component to the required range to obtain a liquid component B;

3) preparation of solid component C: ball-milling and mixing AlCr powder, Si powder and Al powder to obtain a solid component C;

4) preparing a slurry penetrating agent: and uniformly mixing the liquid component A and the liquid component B according to the proportion, then adding the solid component C, adding water for dilution after uniform mixing, and then placing in a vacuum drying oven for drying to obtain the slurry penetrant.

In the step 1), the material mixing sequence is as follows: firstly adding AlCl into partial absolute ethyl alcohol solution₃、NH₄Cl、Cr₂O₃、H₃PO₄Uniformly mixing the solution, adding the rest part of absolute ethyl alcohol, and uniformly mixing; the standing time is 60-100 h.

In the step 2), the standing time is 60-100 h.

In the step 4), the water is added for dilution by 9-11 times according to the mass ratio; the vacuum drying temperature is 50-80 ℃, and the heat preservation time is 16-50 h.

The principle of the invention is as follows:

the solid component C of the invention is added with Al powder which forms an intermediate compound strengthening phase with Ni to generate precipitation strengthening and form compact Al on the surface layer of the coating₂O₃The film improves the high-temperature creep strength, the fatigue resistance, the oxidation resistance and the hot corrosion resistance of the surface of the nickel-based superalloy; addition of Cr element: form Ni-Cr solid solution with Ni, produce solid solution strengthening, and form Cr₂O₃、NiCr₂O₄The composite oxide film improves the high-temperature oxidation resistance and the vulcanization resistance of the surface of the nickel-based high-temperature alloy, and improves the pitting corrosion resistance and the interstitial corrosion resistance. Adding Si powder: the formed dispersion relative coating and the substrate play a role in pinning and blocking, Al inward diffusion and Ni outward diffusion can be prevented, the bonding strength between the coating and the substrate is greatly improved, the service life is prolonged, and Si and Al form an Al-Si inner diffusion layer, so that the bonding strength is improvedThe surface of the nickel-based superalloy has wear resistance;

the components A and B in the invention adopt absolute ethyl alcohol, so that the metal powder is well wetted, the powder agglomeration can be reduced, and the powder distribution is more uniform.

The invention has the beneficial effects that:

1) the aluminized slurry provided by the invention is reasonable in compatibility, moderate in aluminum content and various in addition forms, the infiltration speed and the infiltration layer thickness of aluminum are improved, the toughness of the infiltration layer is ensured, and the mechanical property is improved. The activator, the adhesive and the like all participate or promote the reaction in the high-temperature aluminizing process, no harmful residue is generated, the purity of an aluminized layer is ensured, and the service life of the aluminized coating is prolonged.

2) The aluminum-chromium-silicon slurry prepared by the method greatly improves the sulfur corrosion resistance, the oxygen corrosion resistance, the thermal stability and the coating service life of the aluminum-chromium-silicon coating; meanwhile, the defects of uneven coating thickness, surface nodulation, local aluminum enrichment and the like in the traditional aluminum penetrating agent preparation are overcome. The aluminizing agent is applied to the aerospace engine blade, and the service life of the aerospace plane engine blade is greatly prolonged.

Drawings

FIG. 1 scanning electron micrographs of coating sections obtained by the preparation of the penetrant slurry of examples 1 and 2; (a) example 1; (b) example 2.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with examples are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Example 1

Firstly, preparing a component A by mass fraction: 20%, component B: 40% and component C: 40% of AlCrSi slurry penetrating agent on the surface of the nickel-based superalloy; wherein, the component A: 6% AlCl₃6% NH₄Cl, 10% Cr₂O₃And 24% of H₃PO₄Solution (concentration 85%), and the balance of absolute ethyl alcohol; and (B) component: 15% CrCl₃30% of Al₂O₃And 15% of H₃PO₄Solution (concentration 85%), and the balance of absolute ethyl alcohol; and (3) component C: 60% of spherical AlCr powder, 30% of Si powder and the balance of spherical Al powder, wherein the content of Al in the AlCrSi powder is 60%.

The component A is fully mixed, and the mixing sequence is as follows: firstly adding AlCl into partial absolute ethyl alcohol solution₃、NH₄Cl、Cr₂O₃、H₃PO₄The solution (concentration 85%) is mixed evenly, and then the rest part of the absolute ethyl alcohol solution is added and mixed evenly. Then adding distilled water for dilution, adjusting the density, pH and viscosity of the components to the required range, standing for 80h, and filtering to obtain liquid component A, wherein the concentration of chlorine element is less than 10^-3mol/L, component density of 1.2g/cm³pH 0.3 and viscosity 6X 10^-3Pas。

And fully mixing the component B, diluting, and standing for 72 hours to obtain a liquid component B. The density of the component is 1.2g/cm³pH 1.3 and viscosity 7X 10^-3Pas。

And mixing the AlCr powder, the Cr powder and the spherical Al powder by using a ball mill to prepare a component C.

And uniformly mixing the component A and the component B, adding the component C, uniformly stirring to obtain a slurry, diluting the slurry and ultrapure water according to the ratio of 1:10, then putting the diluted slurry into a vacuum drying oven for drying, adjusting the temperature to 70 ℃, and preserving the temperature for 20 hours to obtain the AlCrSi slurry penetrant.

The obtained AlCrSi slurry permeating agent is sprayed on the blade of the nickel-based high-temperature aircraft engine according to the conventional method, and the cross section of the coating is shown as figure 1 (a).

Example 2

Firstly, preparing a component A by mass fraction: 20%, component B: 40% and component C: 40% of AlCrSi slurry penetrating agent on the surface of the nickel-based superalloy; wherein, the component A: 6% AlCl₃7% NH₄Cl, 12% Cr₂O₃And 22% of H₃PO₄Solution (concentration 85%), and the balance of absolute ethyl alcohol; and (B) component: 16% CrCl₃32% of Al₂O₃And 12% of H₃PO₄Solution (concentration 85%), and the balance of absolute ethyl alcohol; and (3) component C: 55% of spherical AlCr powder, 32% of Si powder and the balance of spherical Al powder, wherein the content of Al in the AlCrSi powder is 60%;

the component A is fully mixed, and the mixing sequence is as follows: firstly adding AlCl into partial absolute ethyl alcohol solution₃、NH₄Cl、Cr₂O₃、H₃PO₄The solution (concentration 85%) is mixed evenly and then added with the rest part of absolute ethyl alcohol to be mixed evenly. Diluting with distilled water, adjusting component density, pH and viscosity to desired ranges, standing for 80 hr, and filtering to obtain liquid component A with chlorine concentration lower than 10^-3mol/L, component density of 1.2g/cm³pH 0.3 and viscosity 6X 10^-3Pas。

And uniformly mixing the component A and the component B, adding the component C, uniformly mixing and stirring to obtain slurry, diluting the slurry and ultrapure water according to the ratio of 1:10, then putting the diluted slurry into a vacuum drying oven, drying, adjusting the temperature to 70 ℃, and preserving the temperature for 20 hours to obtain the AlCrSi slurry penetrant.

The AlCrSi slurry infiltration agent is sprayed on the blade of the nickel-based high-temperature aircraft engine according to the conventional method, and the cross section of the coating is shown in figure 1 (b).

Example 3

Firstly, preparing a component A by mass fraction: 20%, component B: 40% and component C: 40% of AlCrSi slurry penetrating agent on the surface of the nickel-based superalloy; wherein, the component A: 7% AlCl₃8% NH₄Cl, 13% Cr₂O₃And 22% of H₃PO₄Solution (concentration 85%), and the balance of absolute ethyl alcohol; and (B) component: 17% CrCl₃33% of Al₂O₃And 12% of H₃PO₄Solution (concentration 85%), and the balance of absolute ethyl alcohol; and (3) component C: 55% of spherical AlCr powder, 32% of Si powder and the balance of spherical Al powder, wherein the content of Al in the AlCrSi powder is 60%.

And fully mixing the component B, diluting, and standing for 72 hours to obtain a liquid component B. The density of the component is 1.1g/cm³pH 1.3 and viscosity 7X 10^-3Pas。

And finally, spraying the AlCrSi slurry permeating agent on a blade of a nickel-based high-temperature aircraft engine according to a conventional method.

Example 4

Firstly, preparing a component A by mass fraction: 15%, component B: 42% and component C: 43 percent of AlCrSi slurry permeating agent on the surface of the nickel-based superalloy; wherein, the component A: 6% AlCl₃6% NH₄Cl, 10% Cr₂O₃And 24% of H₃PO₄Solution (concentration 85%), and the balance of absolute ethyl alcohol; and (B) component: 15% CrCl₃30% of Al₂O₃And 15% of H₃PO₄Solution (concentration 85%), and the balance of absolute ethyl alcohol; and (3) component C: 60% of spherical AlCr powder, 30% of Si powder and the balance of spherical Al powder, wherein the content of Al in the AlCrSi powder is 60%.

The component A is fully mixed, and the mixing sequence is as follows: firstly adding AlCl into partial absolute ethyl alcohol solution₃、NH₄Cl、Cr₂O₃、H₃PO₄The solution (concentration 85%) is mixed evenly and then added with the rest part of absolute ethyl alcohol to be mixed evenly. Diluting with distilled water, adjusting component density, pH and viscosity to desired ranges, standing for 80 hr, and filtering to obtain liquid component A with chlorine concentration lower than 10^-3mol/L, component density of 1.2g/cm³pH 0.3 and viscosity 7X 10^-3Pas。

And finally, spraying the AlCrSi slurry permeating agent on the blades of the nickel-based high-temperature aircraft engine according to a conventional method.

Example 5

The component A is fully mixed, and the mixing sequence is as follows: firstly adding AlCl into partial absolute ethyl alcohol solution₃、NH₄Cl、Cr₂O₃、H₃PO₄And uniformly mixing the solution (the concentration is 85%), adding the rest part of absolute ethyl alcohol, uniformly mixing, diluting with distilled water to adjust the pH and viscosity, standing for 80 hours, and filtering to obtain a liquid component A. Wherein the concentration of chlorine is less than 10^-3mol/L, component density of 1.0g/cm³pH 1.0 and viscosity 7X 10^-3Pas。

And fully mixing the component B, diluting, and standing for 72 hours to obtain a liquid component B. The density of the component is 1.0g/cm³pH 1.4 and viscosity 11X 10^-3Pas。

And uniformly mixing the component A and the component B, adding the component C, uniformly mixing and stirring to obtain slurry, diluting the slurry and ultrapure water according to the ratio of 1:10, then putting the diluted slurry into a vacuum drying oven for drying, adjusting the temperature to 70 ℃, and preserving the temperature for 25 hours to obtain the AlCrSi slurry penetrant.

The invention carries out oxidation experiments of different embodiments, and the sprayed coating of the embodiments 1-5Cleaning the sample with alcohol, drying, weighing the weight before oxidation with a four-digit electronic balance, placing in a muffle furnace, heating to 1000 deg.C, weighing the mass change after 200h, and calculating the mass change per unit area compared with the surface area of the sample. The experimental result shows that the oxidation resistance of the AlCrSi slurry penetrating agent on the surface of the nickel-based superalloy is greatly improved compared with that of an aluminizing agent prepared by the traditional method (the weight is increased to 1.10mg/cm after 100 hours of the oxidation experiment of the traditional method)²). The mass change after 200h oxidation was: 0.5762mg/cm²、0.6158mg/cm²、0.8704mg/cm²、0.8979mg/cm²、0.9198mg/cm²From the above experimental results, it can be known that the oxidation resistance of the AlCrSi slurry penetrant on the surface of the nickel-based superalloy is significantly improved, and the aluminide coating obtained in example 1 has the best oxidation resistance, which is more than three times of the oxidation resistance of the coating obtained by the conventional method.

FIGS. 1(a) and (b) are sectional scanning electron micrographs of coatings of examples 1 and 2, respectively, of the present invention, and it can be seen from FIG. 1 that the coatings of examples 1 and 2 are relatively uniform, and in particular, the aluminized layer of example 1 has the greatest thickness and the greatest uniformity.

The aluminizing agent prepared by the invention solves the problems of poor oxidation resistance, uneven aluminized layer thickness and the like of the traditional aluminizing agent, is applied to the aerospace engine blade, and greatly prolongs the service life of the aerospace aircraft engine blade.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.

Claims

1. a nickel-based superalloy surface AlCrSi slurry infiltration agent, is characterized in that, its raw material comprises 3 components according to mass percentage, the liquid component A of 18～30%, the liquid component B of 35～60% , the remainder is solid component C;

in:

The raw material of liquid component A is composed of the following components according to the mass percentage: 5~20% AlCl ₃ , 3.7~8.6% NH ₄ Cl, 8~15% Cr ₂ O ₃ and 16~30% H ₃ PO ₄ solutions, the balance is absolute ethanol;

The liquid component B raw material is composed of the following components according to the mass percentage: 10~17.5% CrCl ₃ , 25~35% Al ₂ O ₃ and 10~20% H ₃ PO ₄ solution, and the balance is absolute ethanol ;

Solid component C is solid powder, and the raw material is composed of the following components according to the mass percentage, 50~70% spherical AlCr powder and 30~50% Si powder, and the balance is spherical Al powder;

The concentration of the H ₃ PO ₄ solution in the components A and B is 80-90%; the liquid component A needs to add an appropriate amount of water to adjust the density to be 1.1-1.5 g/cm ³ , the pH value to be 0.2-1.2, and the viscosity to be 0.2-1.2. is (3~15)×10 ^-3 Pa·s; the liquid component B needs to add an appropriate amount of water to adjust the density to be 1.0~1.4 g/cm ³ , the pH value to be 0.8~2.6, and the viscosity to be (5~12)× 10 ^-3 Pa·s; the Al content in the AlCr powder in the component C is 55-70%.

2. nickel-based superalloy surface AlCrSi slurry infiltration agent according to claim 1, is characterized in that, nickel-based superalloy surface AlCrSi slurry infiltration agent, raw material according to mass percentage, consists of the following components, 20% liquid Component A, 40% liquid component B, and the balance is solid component C.

3. The nickel-based superalloy surface AlCrSi slurry infiltration agent according to claim 2, wherein the liquid component A, according to mass percentage, consists of the following components: 6% AlCl ₃ , 6% NH ₄ Cl, 10% Cr ₂ O ₃ and 24% H ₃ PO ₄ solution, the balance is absolute ethanol; the liquid component B is composed of the following components according to the mass percentage: 15% CrCl ₃ , 30% Al ₂ O ₃ and 15% H ₃ PO ₄ solution, the balance is absolute ethanol; the solid component C, according to mass percentage, consists of the following components: 60% spherical AlCr powder, 30 % Si powder, the balance is spherical Al powder, and the Al content in the AlCr powder is 60%.

4. a preparation method of a nickel-based superalloy surface AlCrSi slurry infiltration agent according to any one of claims 1 to 3, comprising the following steps:

1) Preparation of liquid component A: After mixing AlCl ₃ , NH ₄ Cl, Cr ₂ O ₃ , H ₃ PO ₄ solution and absolute ethanol in proportion, stir and mix well, then add an appropriate amount of water to adjust the chlorine element after dilution The concentration of the liquid is lower than 10 ^-3 mol/L, and the density, pH and viscosity of the components are adjusted to the required range, then stand and filter to obtain the liquid component A;

2) Preparation of liquid component B: After mixing CrCl ₃ , Al ₂ O ₃ , H ₃ PO ₄ solution and absolute ethanol in proportion, stir and mix well, and then let stand; then add an appropriate amount of water to adjust the density of the components , pH and viscosity to the desired range to obtain liquid component B;

3) Preparation of solid component C: After ball milling and mixing AlCr powder, Si powder and Al powder, solid component C is obtained;

4) Preparation of slurry penetration agent: Mix liquid component A and liquid component B uniformly according to the proportion, then add solid component C, after mixing uniformly, add water for dilution, and then place it in a vacuum drying box for drying to obtain Slurry penetration agent.

5. The preparation method of AlCrSi slurry infiltration agent on the surface of nickel-based superalloy according to claim 4, characterized in that, in the step 1), the mixing sequence is: first add AlCl ₃ to a part of anhydrous ethanol solution , NH ₄ Cl, Cr ₂ O ₃ , H ₃ PO ₄ solution, after mixing, add the remaining part of anhydrous ethanol to mix evenly; the standing time is 60~100h.

6 . The preparation method of AlCrSi slurry infiltration agent on the surface of nickel-based superalloy according to claim 4 , wherein, in the step 2), the standing time is 60-100 h. 7 .

7. The preparation method of AlCrSi slurry infiltration agent on the surface of nickel-based superalloy according to claim 4, characterized in that, in the step 4), the dilution with water is 9 to 11 times according to the mass ratio; the vacuum holding temperature is 50~80℃, the holding time is 16~50h.