CN100575543C - A method of depositing silicon carbide high-radiation coating on the surface of cobalt-based superalloy - Google Patents

Abstract

A kind of method at the high radiation coating of cobalt base superalloy surface deposition silicon carbide relates to a kind of processing method at the high radiation coating of cobalt base superalloy surface deposition silicon carbide.Purpose is to solve adopting magnetically controlled sputter method commonly used to be difficult to realize the problem of good combination between coat of silicon carbide and the cobalt base superalloy.Realize the step that the inventive method comprises: one, with cobalt base superalloy hydrofluoric acid clean, acetone soln ultrasonic cleaning, spirituous solution ultrasonic cleaning and washed with de-ionized water; Two, the cobalt base superalloy after will handling is sent in the magnetron sputtering vacuum storehouse, and vacuumizes, to cobalt base superalloy heating and insulation; Three, will feed Ar gas in the storehouse, apply pulsed negative bias cobalt base superalloy surface reverse sputtering; Four: the sputtering power starter, to the pre-sputter of target material surface; Five, formal sputtering is carried out on the cobalt base superalloy surface, the high radiation coating of depositing silicon carbide; Six, close all power supplys, treat that temperature is reduced to room temperature in the storehouse, finish deposition.

Description

A method of depositing silicon carbide high-radiation coating on the surface of cobalt-based superalloy

technical field

The invention relates to a process method for depositing a silicon carbide high-radiation coating on the surface of a cobalt-based superalloy.

Background technique

SiC (silicon carbide) has mechanical and thermal properties such as high temperature resistance, high radiation, wear resistance and particle impact resistance, good chemical stability, and high strength. The emissivity of SiC is above 0.9, which makes it the material of choice for the preparation of high-temperature radiation-resistant coatings. After the SiC coating is applied to metal materials, it can not only greatly improve the high temperature resistance, wear resistance and radiation resistance of metal materials, but also all properties can be designed within a certain range, so it has received more and more attention. However, it has not been widely used until now, mainly because the preparation of silicon carbide coatings is usually carried out at extremely high temperatures, and the process is complicated and costly. Magnetron sputtering is a very effective thin film deposition method that can achieve low temperature and high speed deposition of thin films. The preparation of SiC coatings by magnetron sputtering is an important method for low temperature growth of SiC coatings. For the case where the properties of the substrate and the coating material are close, the difference in thermal expansion coefficient is small, and the difference in lattice mismatch is small, people mostly use the magnetron sputtering method without pulse bias applied to the substrate to prepare thin films, and the effect of deposited thin films is compared. Ideal, but for cobalt-based superalloy substrates and silicon carbide coatings, the material properties of the two are quite different, and the thermal expansion coefficients and lattice mismatches of the two are also quite different, and residual stress and defects are prone to occur at the interface , which seriously affects the adhesion of SiC coatings on the surface of Co-based superalloys. If the commonly used magnetron sputtering method is used, it is difficult to achieve a good combination between the silicon carbide coating and the cobalt-based superalloy, and the film deposition effect is poor.

Contents of the invention

The purpose of the present invention is to solve the problem that it is difficult to achieve a good combination between the silicon carbide coating and the cobalt-based superalloy by using the commonly used magnetron sputtering method to deposit a silicon carbide coating on the surface of a cobalt-based superalloy, and the film deposition effect is poor. A method was devised to deposit a silicon carbide high emissivity coating on the surface of a cobalt-based superalloy.

The method of the present invention for depositing a silicon carbide high-radiation coating on the surface of a cobalt-based superalloy comprises the following steps:

Step 1. Clean the cobalt-based superalloy with hydrofluoric acid for 10-20 minutes; then put it into the acetone solution and clean it with ultrasonic waves for 10-20 minutes; then put it into the alcohol solution and clean it with ultrasonic waves for 10-20 minutes; finally use Wash with deionized water for 10-20 minutes;

Step 2. Send the treated cobalt-based superalloy into the magnetron sputtering vacuum chamber, and evacuate the magnetron sputtering vacuum chamber. When the vacuum degree in the magnetron sputtering vacuum chamber reaches 10 ^-4 Pa, Heating the cobalt-based superalloy at a temperature of 25-500°C, and then keeping it warm for 10 minutes to 2 hours;

Step 3: Introduce Ar gas into the magnetron sputtering vacuum chamber, and when the pressure in the magnetron sputtering vacuum chamber reaches 4-6Pa, apply a 300-500V pulse negative bias to perform reverse sputtering cleaning on the surface of the cobalt-based superalloy 10-20 minutes;

Step 4: Apply sputtering power to start the ignition, the power is 60-200W, adjust the Ar gas flow rate between 10sccm-50sccm, and pre-sputter the surface of the target for 3-5 minutes;

Step 5. When the gas pressure in the magnetron sputtering vacuum chamber is adjusted to 0.1-2Pa, apply a pulsed negative bias voltage of 40-200V on the surface of the cobalt-based superalloy, the sputtering power is 150W, and the Ar gas flow rate is 10sccm-50sccm In between, formal sputtering is carried out on the surface of the cobalt-based superalloy to deposit a silicon carbide high-radiation coating;

Step 6: After the formal sputtering is over, all power sources are turned off, and the temperature in the magnetron sputtering vacuum chamber drops to room temperature, and the deposition of the silicon carbide high-radiation coating on the surface of the cobalt-based superalloy is completed.

The invention has the advantages that: the invention utilizes magnetron sputtering to realize low-temperature deposition of a silicon carbide high-radiation coating on the surface of a cobalt-based superalloy. By applying an appropriate pulse bias voltage, the atoms that are not firmly attached to the superalloy substrate are removed, and the surface of the superalloy substrate is purified, so that the adhesion between the silicon carbide coating and the cobalt-based superalloy substrate is greatly enhanced, and high radiation of silicon carbide is realized. Good bonding between the coating and the cobalt-based superalloy. Compared with the commonly used chemical vapor deposition, molecular beam epitaxy and other film preparation technologies, the silicon carbide coating prepared by applying a certain pulse bias voltage: has good compactness; eliminates interface defects between cobalt-based superalloys and SiC coatings and residual stress to achieve a good bond between the silicon carbide coating and the superalloy substrate; it has better radiation characteristics and higher emissivity.

Description of drawings

Fig. 1 is a Fourier transform infrared spectrum analysis diagram of a coating deposited on a cobalt-based superalloy substrate.

Detailed ways

Specific embodiment 1: The present embodiment is described below in conjunction with FIG. 1. The method for depositing a silicon carbide high-radiation coating on the surface of a cobalt-based superalloy in this embodiment includes the following steps:

Step 1. Clean the cobalt-based superalloy with hydrofluoric acid for 10-20 minutes; then put it into the acetone solution and clean it with ultrasonic waves for 10-20 minutes; then put it into the alcohol solution and clean it with ultrasonic waves for 10-20 minutes; finally use Wash with deionized water for 10-20 minutes;

Step 2. Send the treated cobalt-based superalloy into the magnetron sputtering vacuum chamber, and evacuate the magnetron sputtering vacuum chamber. When the vacuum degree in the magnetron sputtering vacuum chamber reaches 10 ^-4 Pa, Heating the cobalt-based superalloy at a temperature of 25-500°C, and then keeping it warm for 10 minutes to 2 hours;

Step 3: Introduce Ar gas into the magnetron sputtering vacuum chamber, and when the pressure in the magnetron sputtering vacuum chamber reaches 4-6Pa, apply a 300-500V pulse negative bias to perform reverse sputtering cleaning on the surface of the cobalt-based superalloy 10-20 minutes;

The solid surface is bombarded with accelerated ions, and the ions exchange momentum with the solid surface atoms, causing the atoms on the solid surface to leave the solid. This process is called sputtering.

We call the impact on the target as sputtering, and the impact on the substrate as reverse sputtering.

Step 4: Apply sputtering power to start the ignition, the power is 60-200W, adjust the Ar gas flow rate between 10sccm-50sccm, and pre-sputter the surface of the target for 3-5 minutes;

The acquisition of charged ions (Ar ⁺ ) is the key to sputtering technology. These charged ions (Ar ⁺ ) are generated in glow discharge, so glow discharge is the basis of sputtering. Glow discharge refers to the The discharge phenomenon produced when a high voltage is applied between two electrodes in a vacuum with a density of about 1Pa to 10Pa is usually referred to as "argon (Ar) ignition".

Before formal sputtering, in order to remove oxides and other impurities on the surface of the target, a certain power is first applied for ignition. In this embodiment, 60-200W is selected to make the energetic ions (Ar ⁺ ) pre-sputter on the surface of the target. At this time, a baffle is used between the target and the substrate to separate the two, so no film will be formed on the surface of the substrate, and the time is usually 3 to 5 minutes.

Step 5. When the gas pressure in the magnetron sputtering vacuum chamber is adjusted to 0.1-2Pa, apply a pulsed negative bias voltage of 40-200V on the surface of the cobalt-based superalloy, the sputtering power is 150W, and the Ar gas flow rate is 10sccm-50sccm In between, formal sputtering is carried out on the surface of the cobalt-based superalloy to deposit a silicon carbide high-radiation coating;

Remove the baffle during formal sputtering to deposit a thin film on the surface of the substrate.

Applying a pulsed negative bias on the surface of the cobalt-based superalloy means that the positive electrode of the bias is grounded (zero point), and the negative electrode is connected to the cobalt-based superalloy (substrate).

Apply a certain pulse negative bias to the substrate, so that the surface of the coating is continuously cleaned by the electric field during the deposition process, and eliminate electrons or other impurities that may enter the coating at any time, which is conducive to improving the purity of the film and making the film denser. .

The time for depositing the thin film in this step is determined by the deposition thickness.

Step 6: After the formal sputtering is over, all power sources are turned off, and the temperature in the magnetron sputtering vacuum chamber drops to room temperature, and the deposition of the silicon carbide high-radiation coating on the surface of the cobalt-based superalloy is completed.

Magnetron sputtering generally installs permanent magnets or electromagnets in the cathode target, and makes the path of the magnetic force lines passing through the cathode of the target perpendicular to the direction of the electric field in order to constrain the movement of charged particles. Those equipped with permanent magnets are called permanent magnet targets, and those equipped with electromagnets are called electromagnetic targets. The principle is that the charged particles on the surface of the target are not only affected by the electric field, but also by the magnetic field of the target, but in a weak magnetic field, electrons with a mass much smaller than ions are more affected. The electrons on the surface of the target are affected by the orthogonal electromagnetic field, and the direction of their movement is constantly changing, and they are constantly orbiting around the cathode surface of the target. While moving toward the anode of the substrate, the moving path is actually greatly extended, which increases the number of collisions between electrons and neutral gas molecules, and significantly increases the number of ionizations. The energy of the electrons that have undergone multiple collisions reaches the anode of the substrate is significantly reduced, which not only improves the sputtering efficiency, but also ensures that the temperature of the substrate will not rise too high, achieving low temperature and high speed sputtering effects.

Figure 1 is a Fourier transform infrared spectrum analysis diagram of the coating deposited on the cobalt-based superalloy substrate. It can be seen from the figure that the silicon carbide coating can be deposited at low temperature by magnetron sputtering.

According to the national standard GB/T 5210-1985 coating adhesion test method, the combination of cobalt-based superalloy substrate and silicon carbide coating was measured. The adhesive tape method was used to test the adhesion of the silicon carbide coating, and the coating did not fall off after testing, indicating that the cobalt-based superalloy was well bonded to the silicon carbide coating.

Based on the national military standard of the People's Republic of China "Infrared Emissivity Measurement Method", the emission method is used to test the emissivity of silicon carbide coatings. At room temperature, the average emissivity of SiC coating is 0.85, and the maximum value of its spectral emissivity exceeds 0.9. The silicon carbide coating deposited on the cobalt-based superalloy substrate has good thermal radiation characteristics and high emissivity, which meets the requirements of being a high-radiation coating on the metal surface.

Embodiment 2: The difference between this embodiment and Embodiment 1 is that in step 1, the cobalt-based superalloy is cleaned with hydrofluoric acid for 15 to 20 minutes; then put into acetone solution and cleaned with ultrasonic waves for 15 to 20 minutes; Then put it into the alcohol solution, clean it with ultrasonic waves for 15-20 minutes; finally wash it with deionized water for 15-20 minutes. Others are the same as the first embodiment.

Embodiment 3: The difference between this embodiment and Embodiment 1 is that in step 2, the heating temperature is 25-200° C., and then the heat preservation is carried out for 40-80 minutes. Others are the same as the first embodiment.

Embodiment 4: The difference between this embodiment and Embodiment 1 is that in step 2, the heating temperature is 100° C., and then the heat preservation is carried out for 1 hour. Others are the same as the first embodiment.

Embodiment 5: The difference between this embodiment and Embodiment 1 is that in step 3, a 450V pulse negative bias is applied to clean the surface of the cobalt-based superalloy by reverse sputtering for 15 to 20 minutes. Others are the same as the first embodiment.

Embodiment 6: The difference between this embodiment and Embodiment 1 is that in step 4, sputtering power is applied to start the ignition. Pre-sputter for 3 to 5 minutes. Others are the same as the first embodiment.

Embodiment 7: This embodiment differs from Embodiment 1 in that in step 5, a pulsed negative bias voltage of 40-120V is applied to the surface of the cobalt-based superalloy. Others are the same as the first embodiment.

Embodiment 8: The difference between this embodiment and Embodiment 1 is that in step 5, a pulsed negative bias of 80V is applied to the surface of the cobalt-based superalloy. Others are the same as the first embodiment.

Embodiment 9: The difference between this embodiment and Embodiment 1 is that the Ar gas flow in step 5 is between 20 sccm and 30 sccm. Others are the same as the first embodiment.

Claims (9)

1, a kind of method at the high radiation coating of cobalt base superalloy surface deposition silicon carbide is characterized in that realizing that this bag method may further comprise the steps:

Step 1, with cobalt base superalloy with hydrofluoric acid clean 10～20 minutes; Put into acetone soln then, use ultrasonic cleaning 10～20 minutes; Put into spirituous solution again, use ultrasonic cleaning 10～20 minutes; Used washed with de-ionized water at last 10～20 minutes;

Step 2, the cobalt base superalloy after will handling are sent in the magnetron sputtering vacuum storehouse, and the magnetron sputtering vacuum chamber is vacuumized, and the vacuum tightness in magnetron sputtering vacuum storehouse reaches 10 ^-4During Pa, to the cobalt base superalloy heating, Heating temperature is 25～500 ℃, is incubated 10 minutes then～2 hours;

Step 3, with feeding Ar gas in the magnetron sputtering vacuum storehouse, when pressure reaches 4～6Pa in the magnetron sputtering vacuum storehouse, apply 300～500V pulsed negative bias and reverse sputtering is carried out on the cobalt base superalloy surface cleaned 10～20 minutes;

Step 4: apply the sputtering power starter, power is 60～200W, regulates the Ar airshed between 10sccm～50sccm, to the pre-sputter of target material surface 3～5 minutes;

Step 5, when regulating in the magnetron sputtering vacuum storehouse between gas pressure intensity to 0.1～2Pa, apply the pulsed negative bias of 40～200V on the cobalt base superalloy surface, sputtering power is 150W, the Ar airshed is between 10sccm～50sccm, carry out formal sputtering on the cobalt base superalloy surface, the high radiation coating of depositing silicon carbide;

Step 6, formal sputtering finish, and close all power supplys, treat that temperature is reduced to room temperature in the magnetron sputtering vacuum storehouse, finish the deposition to the high radiation coating of cobalt base superalloy surface carborundum.

2, a kind of method at the high radiation coating of cobalt base superalloy surface deposition silicon carbide according to claim 1 is characterized in that in the step 1 cobalt base superalloy being used hydrofluoric acid clean 15～20 minutes; Put into acetone soln then, use ultrasonic cleaning 15～20 minutes; Put into spirituous solution again, use ultrasonic cleaning 15～20 minutes; Used washed with de-ionized water at last 15～20 minutes.

3, a kind of method at the high radiation coating of cobalt base superalloy surface deposition silicon carbide according to claim 1 is characterized in that Heating temperature is 25～200 ℃ in the step 2, is incubated 40～80 minutes then.

4, a kind of method at the high radiation coating of cobalt base superalloy surface deposition silicon carbide according to claim 1 is characterized in that Heating temperature is 100 ℃ in the step 2, is incubated 1 hour then.

5, a kind of method at the high radiation coating of cobalt base superalloy surface deposition silicon carbide according to claim 1 is characterized in that applying in the step 3 450V pulsed negative bias reverse sputtering cleaning 15～20 minutes is carried out on the cobalt base superalloy surface.

6, a kind of method according to claim 1 at the high radiation coating of cobalt base superalloy surface deposition silicon carbide, it is characterized in that applying in the step 4 sputtering power starter, power is 60～150W, regulate the Ar airshed between 20sccm～30sccm, to the pre-sputter in sedimentary coat of silicon carbide surface 3～5 minutes.

7, a kind of method at the high radiation coating of cobalt base superalloy surface deposition silicon carbide according to claim 1 is characterized in that applying on the cobalt base superalloy surface in the step 5 pulsed negative bias of 40～120V.

8, a kind of method at the high radiation coating of cobalt base superalloy surface deposition silicon carbide according to claim 1 is characterized in that applying on the cobalt base superalloy surface in the step 5 pulsed negative bias of 80V.

9, a kind of method at the high radiation coating of cobalt base superalloy surface deposition silicon carbide according to claim 1 is characterized in that the Ar airshed is between 20sccm～30sccm in the step 5.

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