CN113897662B - Movable device and method for electropolishing TC4 titanium alloy - Google Patents

Abstract

The invention discloses a device and a method for movably electropolishing TC4 titanium alloy, wherein the device comprises: the device comprises a cathode motion lifting support, an anode sample, a cathode plate and an electrolytic polishing tank; during electrolytic polishing, the top of the cathode plate is aligned with the bottom of the anode sample, and the cathode plate is controlled to move upwards at a constant speed from the bottom of the anode sample through the cathode motion lifting support until the sample is completely polished; the invention can realize the uniform and bright polishing of the surface of the titanium alloy without oxidation.

Description

Device and method for moving electrolytic polishing TC4 titanium alloy

technical field

The invention discloses a device and method for moving electrolytic polishing titanium alloy, relates to electrolytic polishing technology, and belongs to the technical field of precision surface treatment of metal materials.

Background technique

Ti6Al4V is a typical α+β phase titanium alloy, which has the characteristics of high specific strength and specific stiffness, strong toughness and excellent corrosion resistance. It is widely used in the aerospace field and can improve the corrosion resistance of structures. and longevity. The existing electrolytic polishing device generally uses clamps to hold the workpiece to be polished, the workpiece is easy to fall off, and all surfaces of the workpiece are exposed in the electrolyte, resulting in the TC4 titanium alloy being easily oxidized when polished in a strong acid solution, and the discharge between the two plates Inhomogeneous, the sample is over-corroded and pitted. During the electropolishing process, keep the cathode and anode stationary. When the workpiece is placed vertically, the mucous membrane on the surface moves downward due to gravity, resulting in different thicknesses of the mucous membrane in the upper and lower areas, and different polishing rates and polishing effects; if the workpiece is placed horizontally, then The difference in electric field between the two ends of the workpiece is large, the fluidity of the electrolyte is not good, and the failure of the electrolytic polishing is easily caused if the film does not fall off in time.

The electrolytic polishing based on TC4 titanium alloy is easy to be oxidized and the surface uniformity of static electrolytic polishing based on immersion. For this reason, the present invention proposes a device and method for moving electrolytic polishing TC4 titanium alloy based on these two problems.

Contents of the invention

The invention provides a device and method for moving electrolytically polishing TC4 titanium alloy, which can realize uniform and bright polishing on the surface of the titanium alloy without being oxidized.

Technical scheme of the present invention is as follows:

A mobile electropolishing device for TC4 titanium alloy, comprising: a cathode moving lifting support, an anode sample, a cathode plate, and an electropolishing tank;

The cathode movement lifting support is used to support the cathode plate, the cathode plate is connected to the negative pole of the power supply through a conductive wire, and a protective shell (material is plastic, to avoid participating in the reaction) is provided outside the conductive wire;

The surface of the anode sample except the polished surface is covered by a protective shell to ensure that only the polished surface participates in the reaction, and the anode sample is connected to the positive pole of the power supply through the anode conductive rod;

The cathode plate and the anode sample are all vertically arranged in the electropolishing tank and kept parallel, the polished surface of the anode sample is in a relative position to the cathode plate, and a magnetic pole rotor is placed in the electropolishing tank;

One end of the cathode movement lifting bracket is connected to a computer, and the cathode plate is kept moving at a constant speed through a computer program, and the movement direction is from the bottom of the anode sample to the top;

The anode sample is TC4 titanium alloy; the cathode plate is also TC4 titanium alloy;

Furthermore, the width ratio of the cathode and anode remains 1:1, and the height ratio can be arbitrary, preferably the area ratio of the cathode and anode is 1:4.

Utilize device of the present invention to carry out the method for motion type electrolytic polishing TC4 titanium alloy, described method comprises the steps:

(1) The surface of the TC4 titanium alloy substrate is polished with sandpaper, then ultrasonically cleaned, and dried for later use;

(2) Connect the positive pole of the power supply with the TC4 titanium alloy prepared in step (1) as the anode, connect the negative pole of the power supply with the cathode plate, immerse the cathode and anode poles in the electrolyte, and turn on the power supply for electrolytic polishing;

The composition of the electrolyte is: 50-100 g/L of perchloric acid, 5-10 g/L of triethanolamine, and the solvent is acetic acid;

The voltage of the electrolytic polishing is 45-60V, the time is 40-100s, and the horizontal distance between the cathode and anode is 1-2cm;

The top of the cathode plate is aligned with the bottom of the anode sample, and the cathode plate is controlled to move upward at a constant speed from the bottom of the anode sample through the cathode movement lifting bracket, and the moving speed is 1-100mm/s until the sample is completely polished; during the polishing process, the magnetic pole rotor stirs the solution, Promote the flow of electrolyte, ensure the diffusion of ions in the polishing area and the replenishment of electrolyte while promoting the shedding of the film.

Compared with the prior art, the beneficial effects of the present invention mainly include:

(1) The cathode moves upward at a constant speed to polish the sample. The sample is vertically immersed in the electrolyte completely. In this case, the viscous film on the surface flows downward due to gravity. Therefore, when moving from bottom to top, the lower area The polishing is not affected by the polishing of the upper area, which avoids different etching rates and polishing effects due to different thicknesses of the viscous film during static polishing.

(2) During the polishing process, the magnetic pole rotor stirs the solution, promotes the flow of the electrolyte, ensures the diffusion of ions in the polishing area and the replenishment of the electrolyte, and at the same time promotes the shedding of the film.

(3) All surfaces of the titanium alloy are exposed to the electrolyte and are easily oxidized during polishing. The protective shell of the anode sample ensures that only the polished surface is exposed to effectively avoid this problem.

(4) Perchloric acid acetic acid solution has a smooth and bright effect visible to the naked eye on the electrolytic polishing of TC4 titanium alloy.

(5) The experimental operation is simple and safe, the process is stable and efficient, and can be used for the preparation of titanium alloy EBSD samples.

Description of drawings

Fig. 1 is the device diagram of the present invention's movable type electropolishing TC4 titanium alloy, wherein, 1-cathode moving lifting bracket, 2-conductive wire, 3-conductive wire plastic protective case, 4-anode conductive rod, 5-anode sample, 6-Anode sample protection shell, 7-Electrolyte, 8-Cathode plate, 9-Magnetic pole rotor, 10-Electrolytic polishing tank.

Fig. 2 is a surface topography diagram of the titanium alloy substrate and samples after polishing in Examples 1-3.

Fig. 3 is the electrochemical polarization curves of the titanium alloy substrate and samples after polishing in Examples 1-3.

Detailed ways

The present invention is further described below through specific examples, but the protection scope of the present invention is not limited thereto.

Example 1

(1) Sample pretreatment: The thickness of the TC4 titanium alloy base material is 2mm, and it is processed into a rectangle with a side length of 2cm by wire cutting. After cleaning the surface in the solution for 20 minutes, dry it with a hair dryer.

(2) Use a microscope to take a micrograph of the sample before polishing (a in Figure 2) and the corrosion resistance of the test sample (Figure 3).

(3) Electropolishing process parameter setting: carry out in 8% perchloric acid acetic acid electrolyte, and add 7g/L triethanolamine; polishing voltage 20V, polishing time 20s, magnetic pole rotor rotation speed 300r/min, electrode gap 2cm , carried out at room temperature; TC4 titanium alloy sample is used as anode, another TC4 titanium alloy is used as cathode, the ratio of cathode and anode area is 1:4; the top of the cathode plate is aligned with the bottom of the anode sample, and the cathode plate is controlled from the anode test to The bottom of the sample is moved upward at a constant speed at a speed of 1 mm/s until the sample is completely polished.

(4) The electropolished TC4 titanium alloy sample was ultrasonically cleaned with absolute ethanol for 5 minutes, then taken out, and dried with a hair dryer.

(5) Use the microscope again to take pictures of the appearance of the sample (b in Figure 2) and the corrosion resistance of the test sample (Figure 3).

Example 2

(1) Pretreatment and subsequent treatment Refer to (1), (2), (4), and (5) in Example 1.

(2) Electropolishing process parameter setting: carry out in 8% perchloric acid acetic acid electrolyte, and add 7g/L triethanolamine; polishing voltage 40V, polishing time 40s, magnetic pole rotor rotation speed 300r/min, electrode gap 2cm , carried out at room temperature; TC4 titanium alloy sample is used as anode, another TC4 titanium alloy is used as cathode, the ratio of cathode and anode area is 1:4; the top of the cathode plate is aligned with the bottom of the anode sample, and the cathode plate is controlled from the anode test to The bottom of the sample is moved upward at a constant speed at a speed of 1 mm/s until the sample is completely polished.

Example 3

(1) Pretreatment and laser polishing parameter settings refer to (1), (2), (4), and (5) in Example 1.

(2) Electropolishing process parameter setting: carry out in 8% perchloric acid acetic acid electrolyte, and add 7g/L triethanolamine; polishing voltage 60V, polishing time 60s, magnetic pole rotor rotation speed 300r/min, electrode gap 2cm , carried out at room temperature; TC4 titanium alloy sample is used as anode, another TC4 titanium alloy is used as cathode, the ratio of cathode and anode area is 1:4; the top of the cathode plate is aligned with the bottom of the anode sample, and the cathode plate is controlled from the anode test to The bottom of the sample is moved upward at a constant speed at a speed of 1 mm/s until the sample is completely polished.

Surface morphology ( FIG. 2 ) and corrosion resistance analysis ( FIG. 3 ) were performed on the electropolished TC4 titanium alloy sample above, and it was found that the sample in Example 3 had the best electrolytic polishing effect.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims (5)

1. A device for moving type electropolishing TC4 titanium alloy, characterized in that, said device comprises: cathode movement lifting support, anode sample, cathode plate, electropolishing tank; The cathode movement lifting bracket is used to support the cathode plate, the cathode plate is connected to the negative pole of the power supply through a conductive wire, and a protective shell is provided outside the conductive wire; The surface of the anode sample except the polished surface is covered by a protective shell to ensure that only the polished surface participates in the reaction, and the anode sample is connected to the positive pole of the power supply through the anode conductive rod; The cathode plate and the anode sample are all vertically arranged in the electropolishing tank and kept parallel, the polished surface of the anode sample is in a relative position to the cathode plate, and a magnetic pole rotor is placed in the electropolishing tank; One end of the cathode moving lifting bracket is connected to a computer, the top of the cathode plate is aligned with the bottom of the anode sample, and the cathode plate is kept moving at a constant speed through a computer program, and the movement direction is from the bottom of the anode sample to the top until the sample is completely polished; The anode sample is TC4 titanium alloy; the cathode plate is also TC4 titanium alloy. 2. The device for moving electropolishing TC4 titanium alloy according to claim 1, characterized in that the width ratio of cathode and anode remains 1:1. 3. The device for moving electropolishing TC4 titanium alloy according to claim 1, wherein the area ratio of cathode and anode is 1:4. 4. a method utilizing device described in claim 1 to carry out motion type electrolytic polishing TC4 titanium alloy, is characterized in that, described method comprises the steps: (1) Grind the surface of the TC4 titanium alloy substrate with sandpaper, then ultrasonically clean it, and dry it for later use; (2) Connect the positive pole of the power supply with the TC4 titanium alloy prepared in step (1) as the anode, connect the cathode plate to the negative pole of the power supply, immerse the cathode and anode in the electrolyte, and turn on the power supply for electrolytic polishing; The composition of described electrolytic solution is: perchloric acid 50～100g/L, triethanolamine 5～10g/L, and solvent is acetic acid; The voltage of the electrolytic polishing is 45~60V, the time is 40~100s, and the horizontal distance between the cathode and anode is 1~2cm; The top of the cathode plate is aligned with the bottom of the anode sample, and the cathode plate is controlled to move upward at a constant speed from the bottom of the anode sample through the cathode movement lifting bracket until the sample is completely polished; the magnetic pole rotor stirs the solution during the polishing process. 5. The method according to claim 4, wherein the moving speed of the cathode plate is 1 to 100 mm/s.

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