CN112553625A

CN112553625A - Active element Hf modified beta-NiAl coating and preparation process thereof

Info

Publication number: CN112553625A
Application number: CN202011410297.0A
Authority: CN
Inventors: 姜肃猛; 张文璐; 李伟; 傅霖兵; 李淑梅; 李运通; 宫骏; 孙超
Original assignee: Institute of Metal Research of CAS
Current assignee: Institute of Metal Research of CAS
Priority date: 2020-12-04
Filing date: 2020-12-04
Publication date: 2021-03-26
Anticipated expiration: 2040-12-04
Also published as: CN112553625B

Abstract

The invention discloses an active element Hf modified beta-NiAl coating and a preparation process thereof, belonging to the technical field of high-temperature protective coatings. The Hf modified beta-NiAl coating is prepared on the Ni-based high-temperature alloy through a composite electroplating and arc ion plating process. The method comprises the following steps: compositely electroplating a Ni-Hf layer on the substrate; depositing an Al layer on the obtained Ni-Hf layer using arc ion plating; and annealing the obtained electroplated Ni-Hf + arc ion plating deposition Al layer in a vacuum annealing furnace to obtain the Hf modified beta-NiAl coating. The invention has the advantages that: the preparation process is simple and the cost is low; adding Hf element into the coating by adopting a composite electroplating method; the contents of Hf and Al elements in the coating and the thickness of the coating can be precisely controlled.

Description

Active element Hf modified beta-NiAl coating and preparation process thereof

Technical Field

The invention relates to the technical field of preparing high-temperature protective coatings on high-temperature alloy substrates, in particular to a beta-NiAl coating modified by an active element Hf and a preparation process thereof.

Background

The nickel-based superalloy has high toughness, strength, oxidation resistance, and good workability and thermal conductivity under high temperature conditions, and thus is widely used for turbine blades of aircraft engines and gas turbines. The turbine blade is a key part of an aeroengine and a gas engine, the turbine blade is often damaged by high-temperature oxidation and hot corrosion environments when working in a very harsh environment, the working temperature of the blade is very high, and the stress is complex.

High temperature protective coatings can be classified as simple aluminide coatings, modified aluminide coatings, MCrAlY coatings, and thermal barrier coatings. The simple aluminide coating is prepared through embedding aluminizing, slurry aluminizing, chemical vapor deposition, etc. The preparation process is simple, the cost is low, and a complete and compact aluminum oxide film can be formed under the high-temperature condition. Therefore, simple aluminide coatings have been widely used in industry. But the hot corrosion resistance is poor, and the oxide film is easy to peel off, so that the long-term oxidation resistance of the coating is poor. The addition of Zr, Y, Re, Hf and other active elements into the simple aluminide coating can raise the binding force and hot corrosion resistance of the oxide film obviously. In addition, the aluminide coating has larger composition difference with the base alloy, and serious element interdiffusion occurs in the coating preparation and service processes, namely Al in the coating diffuses inwards into the base and Ni and refractory elements (W, Nb) in the base diffuse outwards into the coating, so that the high-temperature oxidation resistance of the coating is reduced, and the mechanical property of the base is influenced.

The active element Hf has higher chemical activity and can react with O to generate HfO at the interface of the oxide film and the coating₂Plays a role of pinning and can also prevent the segregation of S at the interface of the oxide film and the coating, thereby improving the bonding force of the oxide film; in addition, Hf acts to block Al from Al₂O₃To reduce the oxidation rate of the coating. Common methods for preparing Hf modified aluminide coatings are electron beam physical vapor deposition, magnetron sputtering, chemical vapor deposition, and the like. However, it is difficult to control the Hf content and distribution in the coating during chemical vapor deposition. It is very important to control the Hf content in the coating in Hf modified aluminide coatings, which hardly works if the Hf content in the coating is too low; the Hf content in the coating is too high and severe internal oxidation can occur during oxidation, accelerating coating failure. The Hf modified aluminide coating is prepared by two steps of composite electroplating Ni-Hf and arc ion Al plating, the content and distribution of Hf in the coating can be effectively controlled, and the Ni-Hf layer can be used as a buffer layer to reduce the mutual diffusion of elements between the coating and a base alloy. Therefore, the invention aims to provide a preparation method which can add Hf element into a beta-NiAl coating and can control the content and distribution of Hf in the coating.

Disclosure of Invention

The invention aims to provide an active element Hf modified beta-NiAl coating and a preparation process thereof, namely, the Hf-containing beta-NiAl coating is prepared by using composite electroplating and arc ion plating technologies.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a preparation process of an active element Hf modified beta-NiAl coating comprises the following steps:

(1) carrying out pretreatment on a sample to be coated;

(2) carrying out composite electroplating on the sample pretreated in the step (1), depositing a Ni-Hf layer on the surface of the sample, and adding an element Hf into the coating;

(3) depositing a pure Al layer on the Ni-Hf layer obtained by the composite electroplating in the step (2) by adopting arc ion plating;

(4) and (4) annealing the coating obtained in the step (3) to prepare the active element Hf modified beta-NiAl coating.

In the step (1), the sample is a nickel-based superalloy; the sample pretreatment process comprises the following steps: the superalloy was first cut into square specimens 15mm by 10mm by 1.5mm by wire cutting, and one specimen was cut 1mm from one end of the specimen

The small holes are convenient for hanging samples; then sequentially using SiC sand paper of 150#, 240#, 400#, 600#, and 800# to polish the sample; carrying out wet sand blasting treatment on the sample by adopting 200-mesh alumina pellets; and finally, respectively ultrasonically cleaning the sample in deionized water, acetone and alcohol for 15 min.

In the step (1), the sample pretreatment comprises electrochemical oil removal and activation which are sequentially carried out; the electrochemical oil removal process comprises the following steps: in 5-15g/L NaOH solution, the substrate is used as cathode, the stainless steel plate is used as anode, and the current density is 2-15A/dm²The oil removing time is 1-10 min; the activation process comprises the following steps: the samples were soaked in 10-30 vol.% hydrochloric acid for 1-5min at room temperature.

In the step (2), when the Ni-Hf composite plating is carried out, the plating solution comprises the following components: ni₂SO₄·6H₂O is 240-250g/L, NiCl₂·6H₂O is 35-50g/L, H₃BO₃35-40g/L, saccharin 0.6-1g/L, C₁₂H₂₅NaSO₄0.1-0.2g/L, 20-60g/L of Hf powder and the balance of deionized water; wherein the particle size of the Hf powder is 0.5-2 mu m; the composite electroplating process parameters are as follows: pH of 4-5, temperature of 35-55 deg.C, and current density of 1-4A/dm²Electroplating for 20-60 min; the thickness of the obtained Ni-Hf layer is 10-30 μm.

In the step (3), the process parameters of arc ion plating deposition of pure Al are as follows: arc current is 60-90A, arc voltage is 20-30V, and deposition time is 60-120 min; the thickness of the pure Al layer obtained is 10-50 μm.

In the step (4), the annealing treatment is to place the sample in a vacuum annealing furnace, heat the annealing furnace to 950-.

The active element Hf modified beta-NiAl coating is prepared on the surface of the nickel-based superalloy by adopting the process, the coating consists of an inner-layer interdiffusion zone and an outer layer, and the outer layer is mainly a beta-NiAl phase and a Hf precipitated phase. The coating comprises the following chemical components: hf is 0.05-3 wt.%, Al is 20-40 wt.%, and Ni is 60-80 wt.%.

The invention has the following advantages:

1. the invention adopts a composite electroplating method to add Hf into the beta-NiAl coating, and the preparation cost is lower.

2. The invention adopts a process of combining electroplating and arc ion plating, and the prepared Hf modified beta-NiAl coating consists of an inner interdiffusion zone and an outer layer, wherein the outer layer is mainly a beta-NiAl phase and a Hf precipitated phase.

3. The invention adopts a method combining electroplating and arc ion plating to prepare the active element modified beta-NiAl coating. The contents of the Hf and Al elements in the coating and the thickness of the coating can be precisely controlled.

Drawings

FIG. 1 is a cross-sectional view of a composite electroplated Ni-Hf layer.

FIG. 2 is an XRD pattern of the Hf modified beta-NiAl coating after annealing.

FIG. 3 is a cross-sectional profile of the Hf modified beta-NiAl coating after annealing.

Detailed Description

The invention is described in detail below with reference to the accompanying drawings and examples.

Example 1

The nickel-base superalloy matrix comprises the following components (unit: wt.%): cr: 16.0, Co: 8.0, W: 2.5, Al: 4.0, Nb: 1.0, Ti: 4.0, Mo: 2.0, Ta: 1.5, C: 0.1, B: 0.005 and the balance of Ni. The superalloy was cut into square specimens of 15X 10X 1.5mm using wire cutting, and 1mm from one end of the specimenIs cut into one

The small holes are convenient for hanging the sample.

The sample was subjected to surface treatment. Firstly, sequentially using the SiC sand paper of 150#, 240#, 400#, 600# and 800#, grinding and chamfering the sample; then, carrying out wet sand blasting treatment on the sample by adopting 200-mesh alumina pellets; and finally, respectively ultrasonically cleaning the sample in deionized water, acetone and alcohol for 15 min.

And (3) pretreating the sample, namely electrochemically removing oil and then activating. The electrochemical oil removing process comprises the steps of taking a substrate as a cathode and a stainless steel plate as an anode in 5g/L NaOH solution, wherein the current density is 8A/dm²Removing oil for 1 min; the activation process comprises the following steps: the samples were soaked in 20 vol.% hydrochloric acid for 1min at room temperature.

Putting the pretreated sample into an electroplating solution to carry out Ni-Hf electroplating. The plating solution comprises the following components: 250g/L Ni₂SO₄·6H₂O，50g/L NiCl₂·6H₂O，40g/L H₃BO₃0.6g/L saccharin, 0.1g/L C₁₂H₂₅NaSO₄20g/L of Hf powder and the balance of deionized water. Wherein the particle size of the Hf powder is 1 mu m, and the electroplating process comprises the following steps: the pH of the plating solution is 4.5, the temperature is 45 ℃, and the current density is 2A/dm²The Ni-Hf alloy is electroplated for 30min to obtain a Ni-Hf alloy layer with a thickness of about 13 μm.

And depositing an Al layer on the sample plated with the Ni-Hf by adopting an arc ion plating technology. The thickness of the Al layer is about 30 μm. The detailed arc ion plating process is shown in table 1.

TABLE 1 arc ion plating Al layer deposition Process

And (3) placing the sample deposited with the Al layer into a vacuum annealing furnace, heating to 1080 ℃, preserving heat for 3 hours, and cooling along with the furnace. The heating rate was 10 ℃/min.

In this embodiment. FIG. 1 is a cross-sectional view of a composite electroplated Ni-Hf layer. It can be seen that the thickness of the plated layer was about 13 μm, and Hf was uniformly distributed in the plated layer.

FIG. 2 is an XRD pattern of the Hf modified beta-NiAl coating after annealing. It can be seen that the coating is composed mainly of a beta-NiAl phase and a small amount of a precipitate phase of Hf.

FIG. 3 is a cross-sectional profile of the Hf modified beta-NiAl coating after annealing. It can be seen that the overall coating thickness is about 40 μm and consists of an inner interdiffusion zone and an outer layer, which is predominantly a β -NiAl phase and a bright white precipitate Hf. When the results of EDS and XRD are combined, the bright white precipitated phase of the coating outer layer is Hf. In contrast to the distribution of Hf in the electroplated layer, Hf diffuses to the outer layer of the coating during annealing. The Hf content in the coating was 0.7 wt.%, the Al content was 24.0 wt.%, the Cr content was 0.5 wt.%, the Co content was 1.0 wt.%, and the balance was Ni.

Claims

1. A preparation process of an active element Hf modified beta-NiAl coating is characterized by comprising the following steps: the process comprises the following steps:

(1) carrying out pretreatment on a sample to be coated;

2. The process for preparing a beta-NiAl coating modified by active element Hf according to claim 1, wherein: in the step (1), the sample is a nickel-based superalloy; the sample pretreatment process comprises the following steps: the superalloy was first cut into square specimens 15mm by 10mm by 1.5mm by wire cutting, and one specimen was cut 1mm from one end of the specimen

The small holes are convenient for hanging samples; then using 150#, 240#, 400#, 600#, 800# in sequencePolishing the sample by using SiC abrasive paper; carrying out wet sand blasting treatment on the sample by adopting 200-mesh alumina pellets; and finally, respectively ultrasonically cleaning the sample in deionized water, acetone and alcohol for 15 min.

3. The process for preparing a beta-NiAl coating modified by active element Hf according to claim 1, wherein: in the step (1), sample pretreatment comprises electrochemical oil removal and activation which are sequentially carried out; the electrochemical oil removal process comprises the following steps: in 5-15g/L NaOH solution, the substrate is used as cathode, the stainless steel plate is used as anode, and the current density is 2-15A/dm²The oil removing time is 1-10 min; the activation process comprises the following steps: the samples were soaked in 10-30 vol.% hydrochloric acid for 1-5min at room temperature.

4. The process for preparing a beta-NiAl coating modified by active element Hf according to claim 1, wherein: in the step (2), when Ni-Hf composite electroplating is carried out, the plating solution comprises the following components: ni₂SO₄·6H₂O is 240-250g/L, NiCl₂·6H₂O is 35-50g/L, H₃BO₃35-40g/L, saccharin 0.6-1g/L, C₁₂H₂₅NaSO₄0.1-0.2g/L, 20-60g/L of Hf powder and the balance of deionized water; wherein the particle size of the Hf powder is 0.5-2 mu m; the composite electroplating process parameters are as follows: pH of 4-5, temperature of 35-55 deg.C, and current density of 1-4A/dm²Electroplating for 20-60 min; the thickness of the obtained Ni-Hf layer is 10-30 μm.

5. The process for preparing a beta-NiAl coating modified by active element Hf according to claim 1, wherein: in the step (3), the technological parameters of arc ion plating deposition of pure Al are as follows: arc current is 60-90A, arc voltage is 20-30V, and deposition time is 60-120 min; the thickness of the pure Al layer obtained is 10-50 μm.

6. The process for preparing a beta-NiAl coating modified by active element Hf according to claim 1, wherein: in the step (4), the annealing treatment is to place the sample in a vacuum annealing furnace, heat the annealing furnace to 950 ℃ and 1100 ℃ at the heating rate of 5-10 ℃/min, preserve the temperature for 1-4h, and then cool the sample to room temperature along with the furnace.

7. A reactive element Hf modified β -NiAl coating prepared by the method of any one of claims 1 to 6, wherein: the coating is prepared on the surface of the nickel-based superalloy, and comprises the following chemical components: hf is 0.05-3 wt.%, Al is 20-40 wt.%, and Ni is 60-80 wt.%.

8. The reactive element, Hf-modified β -NiAl coating of claim 7, wherein: the coating consists of an inner interdiffusion zone and an outer layer, wherein the outer layer is mainly a beta-NiAl phase and a Hf precipitated phase.