Electrolyte, polishing medium and polishing method for solid electrolytic polishing of titanium or titanium alloy

Abstract

The invention discloses an electrolyte, a polishing medium and a polishing method for solid electrolytic polishing of titanium or titanium alloy. The electrolyte comprises an inorganic salt and a solvent; wherein the solvent comprises a polar organic solvent, or a polar organic solvent and water; the resistivity of the polar organic solvent is ≤5×10 7 Ω / cm; the inorganic salt includes at least one of chloride salt, fluoride salt, sulfate and nitrate. The present invention provides a fast, low-carbon, environmentally friendly and high-quality polishing technology solution for titanium or titanium alloy, a special metal / alloy product, to achieve high brightness and low roughness.

Description

Technical Field

[0001] The invention relates to the technical field of metal surface treatment, in particular to an electrolyte, a polishing medium and a polishing method for solid electrolytic polishing of titanium or titanium alloy. Background Art

[0002] Titanium metal has the advantages of light weight, high strength and corrosion resistance. Titanium alloy is an alloy composed of titanium and other elements. Titanium alloy has high strength, good corrosion resistance, high heat resistance, and extremely excellent biocompatibility. It has been widely used in biological implant materials, aerospace equipment, special equipment, and deep-sea equipment.

[0003] Due to its excellent corrosion resistance, high temperature resistance, high strength and high toughness, titanium alloys require multiple steps of manual polishing to achieve a smooth surface, and general chemical polishing and electrochemical polishing processes are ineffective. The high strength of the material also makes manual polishing much more difficult, with a long construction period, and it is difficult to obtain uniform standards and a low defect rate, and it is difficult to achieve a high level of polishing effect on corners and gaps. This is a huge shortcoming for the high-standard and high-demand aerospace industry.

[0004] In the prior art, CN113699579A discloses that the workpiece to be polished is first electropolished with aqueous solution under mild electrolytic conditions, so that the surface of the workpiece to be polished reaches a preliminary brightness, and then the polished workpiece with a spherical solid electrolyte is subjected to composite electropolishing, so that the surface of the workpiece to be polished reaches the final mirror brightness. Although it can achieve a mirror brightness surface, the process is relatively complicated. At the same time, its composite electropolishing is a mechanical action and an electrolytic action acting at the same point at the same time. Due to the huge difference in hardness between the particles and the metal sample, when the mechanical action is too intense, the spherical solid will inevitably be destroyed, making the spherical solid unable to be recycled, and the cost of composite electropolishing increases. CN109415839A discloses smoothing and polishing of metal parts by solid particles containing conductive liquid. It mainly realizes electrochemical polishing by the conductive action of the conductive liquid. The conventional liquid phase electrochemical polishing is converted into solid phase polishing by the adsorption of the conductive liquid by the porous material, but its essence is no different from liquid phase electrochemical polishing. CN111032929A, CN113195799A, CN112534088A, CN115038822A, etc. disclose the use of strong acid electrolyte solutions such as sulfuric acid, hydrochloric acid, sulfonic acid, etc. as conductive liquids in solid phase polishing. However, strong acid electrolytes are highly dangerous to users, and transportation and post-processing are also difficult.

[0005] CN114908409A, CN114908410A, and CN115029768A disclose a series of porous solid particles having carboxyl groups, amino groups, and hydroxyl groups, and propose the mechanism of ion exchange. However, there is no satisfactory solid electrolytic polishing technology solution for titanium or titanium alloys. Summary of the invention

[0006] The present invention aims to solve the technical problems of solid electrolytic polishing of titanium or titanium alloys existing in the prior art. To this end, the present invention aims to further optimize special metal / alloy products such as titanium or titanium alloys on the basis of previous inventions. To this end, one of the purposes of the present invention is to provide an electrolyte for solid electrolytic polishing of titanium or titanium alloys, a second purpose of the present invention is to provide a polishing medium for solid electrolytic polishing of titanium or titanium alloys, a third purpose of the present invention is to provide a method for preparing such a polishing medium, and a fourth purpose of the present invention is to provide a method for solid electrolytic polishing of titanium or titanium alloys. The titanium or titanium alloy described in the present invention refers to titanium metal, or titanium alloy.

[0007] It should be noted that electropolishing is to immerse the metal in a special chemical solution composed of various components, relying on high electrochemical potential to oxidize the metal to obtain a smooth and bright surface. The chemical solution used in conventional electropolishing is a strong acid or a highly volatile liquid, which is not convenient for transportation and storage, and is harmful to workers. Waste liquid treatment is also a big problem. Solid electropolishing, on the other hand, uses solid particles with ion adsorption / exchange / complexation capabilities and an internal conductive solution to replace the electrolyte. The solid particles are in contact with the metal parts to be polished, thereby achieving polishing of the surface of the metal parts. Although the solid particles are in contact with the metal parts to be polished, the relative movement rate of this contact is low, and the hardness of the solid particles is lower than that of the metal parts, so the physical mechanical polishing process can be ignored.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A first aspect of the present invention provides an electrolyte for solid electrolytic polishing of titanium or titanium alloy, comprising an inorganic salt and a solvent;

[0010] The solvent includes a polar organic solvent, or a polar organic solvent and water;

[0011] The resistivity of the polar organic solvent is ≤5×10 7 Ω / cm;

[0012] The inorganic salt includes at least one of chloride salt, fluoride salt, sulfate and nitrate.

[0013] The electrolyte of the invention plays the role of conducting electricity and transmitting ions in the solid electrolytic polishing of titanium or titanium alloy.

[0014] Preferably, the polar organic solvent includes at least one of small molecule alcohols, small molecule ketones, dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, dioxane, and ionic liquids.

[0015] Preferably, the small molecule alcohol includes at least one of methanol, ethanol, n-propanol, isopropanol, butanol, and butanediol. In some specific embodiments of the present invention, the small molecule alcohol is ethanol. In some specific embodiments, the small molecule alcohol is an anhydrous ethanol solution.

[0016] Preferably, the small molecule ketone includes at least one of acetone, butanone and cyclohexanone.

[0017] Preferably, the mass percentage of the inorganic salt in the solvent is 0.01% to 5%; further preferably, the mass percentage of the inorganic salt in the solvent is 0.01% to 2%; further preferably, the mass percentage of the inorganic salt in the solvent is 0.1% to 1.5%; further preferably, the mass percentage of the inorganic salt in the solvent is 0.1% to 1%; further preferably, the mass percentage of the inorganic salt in the solvent is 0.1% to 0.5%.

[0018] Preferably, the inorganic salt is selected from one of sodium chloride and sodium sulfate or a combination thereof. In some specific embodiments of the present invention, the inorganic salt is sodium chloride.

[0019] Preferably, when the solvent includes a polar organic solvent and water, the mass percentage of the polar organic solvent in the solvent is 90.01% to 99.99%; further preferably, the mass percentage of the polar organic solvent in the solvent is 95% to 99.99%; even further preferably, the mass percentage of the polar organic solvent in the solvent is 97% to 99.99%.

[0020] A second aspect of the present invention provides a polishing medium for solid electrolytic polishing of titanium or titanium alloy, comprising:

[0021] Solid particles, the solid particles having a porous structure and groups capable of adsorbing and complexing metal ions;

[0022] The electrolyte described in the first aspect of the present invention is located inside the solid particles, or inside and on the surface of the solid particles.

[0023] It should be noted that the electrolyte can adjust the conductivity and ion exchange rate of the solid particles.

[0024] Preferably, the mass percentage of the electrolyte in the polishing medium is 30% to 70%. When the pores of the solid particles are completely filled with the electrolyte, it is saturated adsorption. Further preferably, the mass percentage of the electrolyte in the solid particles is 30% to 60%; further preferably, the mass percentage of the electrolyte in the solid particles is 40% to 50%.

[0025] Preferably, in the solid particulate matter, the groups that adsorb and complex metal ions include at least one of carboxyl, amine and hydroxyl groups.

[0026] The solid particles of the present invention have a porous structure, are hydrophilic and have a certain hardness, will not break easily when slightly collided with titanium or titanium alloy, can absorb a certain amount of alcohol solution and have conductivity and ion exchange properties, and may not have conductivity itself. The solid particles have groups that can adsorb and complex metal ions, thereby playing a role in fixing metal ions, reducing the concentration of metal ions in the electrolyte, reducing overpotential, and promoting the oxidation process on the surface of the metal sample.

[0027] Preferably, the solid particulate matter includes one or more of ion exchange resin, silica gel, molecular sieve; further preferably, the solid particulate matter includes one or more of ion exchange resin, silica gel, molecular sieve containing at least one of carboxyl, hydroxyl, and amine groups; further preferably, the solid particulate matter includes an acrylic ion exchange resin containing at least one of carboxyl, hydroxyl, and amine groups. The acrylic ion exchange resin containing at least one of carboxyl, hydroxyl, and amine groups can be prepared by polymerizing monomers containing carboxyl, hydroxyl, or amine groups with acrylic acid (ester) monomers, which is a conventional method in the art, such as those disclosed in CN114908409A, CN114908410A, and CN115029768A, or directly purchasing commercially available products. Further preferably, the solid particulate matter is a material containing COOH / COO - Carboxylic acid type acrylic ion exchange resin.

[0028] The third aspect of the present invention provides a method for preparing the polishing medium for solid electrolytic polishing of titanium or titanium alloy according to the second aspect of the present invention, comprising the following steps:

[0029] S1: soaking the solid particles in a solution containing a pH regulator, stirring, filtering and drying after the pH value stabilizes, to obtain a solid particle intermediate;

[0030] S2: soaking the solid particle intermediate in an electrolyte containing an inorganic salt and a solvent, stirring, filtering, and drying to obtain the polishing medium for solid electrolytic polishing of titanium or titanium alloy.

[0031] The first step S1 of the polishing medium preparation method aims to adjust the pH of the solid particles and remove the water adsorbed inside; the second step S2 aims to allow the solid particles to be adsorbed into the required electrolyte.

[0032] Preferably, in S1 of the preparation method, the solid particles are dried before use.

[0033] Preferably, in S1 or S2 of the preparation method, the air-drying method is air-drying at room temperature.

[0034] In S2 of the preparation method, the mass content of the electrolyte in the polishing medium can be controlled by controlling different drying times.

[0035] Preferably, in S1 of the preparation method, waiting for the pH value to be stabilized is waiting for the pH value to be stabilized to 5-9; more preferably, waiting for the pH value to be stabilized to 6-8; and even more preferably, waiting for the pH value to be stabilized to 6-7.

[0036] Preferably, in S1 of the preparation method, the pH regulator includes an acidic or alkaline substance that can adjust the pH. Among them, the acid can be selected from sulfuric acid, hydrochloric acid, nitric acid or an organic acid; the base can be selected from sodium hydroxide, potassium hydroxide or an organic amine. The acidic or alkaline substance can be selected according to different solid particles, and then the pH value of the solid particles can be adjusted. For example, an alkaline substance can be selected for acidic solid particles, and an acidic substance can be selected for alkaline solid particles.

[0037] Preferably, in S1 of the preparation method, the solution containing the pH adjuster is an alcohol solution containing the pH adjuster. The alcohol is preferably a C1-C4 alcohol solution.

[0038] A fourth aspect of the present invention provides a solid electrolytic polishing method for titanium or titanium alloy, comprising the following steps:

[0039] 1) placing the polishing medium for solid electrolytic polishing of titanium or titanium alloy described in the second aspect of the present invention and the titanium or titanium alloy to be polished in an electrochemical polishing device;

[0040] Wherein, the polishing medium of the titanium or titanium alloy solid electrolytic polishing is connected to the negative electrode of the power supply of the electrochemical polishing device, and the titanium or titanium alloy to be polished is connected to the positive electrode of the power supply of the electrochemical polishing device;

[0041] 2) The electrochemical polishing device is powered on to perform electrolytic polishing. During electrolytic polishing, the titanium or titanium alloy to be polished and the polishing medium undergo relative friction movement.

[0042] Preferably, in step 2), the applied voltage is 20V to 120V; further preferably, the applied voltage is 70V to 100V.

[0043] Preferably, in step 2), the rate of relative friction movement is 20 r / min to 120 r / min; further preferably, the rate of relative friction movement is 80 r / min to 100 r / min.

[0044] Preferably, in step 2), the polishing time is 10 min to 90 min; more preferably, the polishing time is 30 min to 60 min.

[0045] The beneficial effects of the present invention are:

[0046] The present invention provides a fast, low-carbon, environmentally friendly, high-quality polishing technology solution for special metal / alloy products such as titanium or titanium alloys, which can achieve high brightness and low roughness.

[0047] Specifically, the present invention has the following advantages:

[0048] 1. The polishing medium used in the present invention is solid particles, which is convenient for transportation and post-processing.

[0049] 2. The solid particle polishing material of the present invention can be regenerated after being used for a period of time, which greatly increases the service life and reduces the cost.

[0050] 3. The polishing scheme provided by the present invention can fully polish titanium or titanium alloy parts in all directions without dead angles, with low energy consumption, strong consistency, no need for manual labor, greatly shortening the process, and facilitating automated operation, thereby solving the problems of high pollution, high energy consumption, high defect rate, long process, and difficulty in automation in the existing titanium or titanium alloy polishing. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below by specific examples. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial sources or can be obtained by prior art methods. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0052] The carboxylic acid type acrylic acid ion exchange resin used below is a COOH type acrylic acid ion exchange resin prepared by referring to the preparation method of polyacrylate porous resin microspheres with carboxyl groups disclosed in the specific embodiment of CN114908409A. The carboxylic acid type acrylic acid ion exchange resins used in the examples and comparative examples are the same. The resistivity of the anhydrous ethanol solution used below is 1.9×10 5 Ω / cm.

[0053] Example 1

[0054] The electrolyte for solid electrolytic polishing of titanium or titanium alloy in this example contains sodium chloride and a solvent. The solvent is composed of 99.9wt% ethanol and 0.1wt% water. The mass content of sodium chloride in the solvent is 0.2%.

[0055] The polishing medium for solid electrolytic polishing of titanium or titanium alloy in this example is prepared by the following preparation method:

[0056] Take 20 kg of anhydrous ethanol solution, add a certain amount of sodium hydroxide and 10 kg of air-dried carboxylic acid type acrylic acid ion exchange resin, stir well, filter after the pH stabilizes to 6.5, and dry at room temperature to obtain treated solid particles.

[0057] Then take 19.98 kg of anhydrous ethanol solution, add 40 g of sodium chloride, 20 g of water and the treated solid particles, stir well, filter, and dry at room temperature to obtain the polishing medium of this example.

[0058] In the polishing medium of this example, the content of the electrolyte is 50wt%.

[0059] The test method for the mass content of electrolyte in the polishing medium is to place the final polishing medium in a 150°C forced air drying oven, and then calculate according to the following formula: mass content of electrolyte = (weight loss mass ÷ polishing medium before test) × 100%.

[0060] Example 2

[0061] The electrolyte for solid electrolytic polishing of titanium or titanium alloy in this example contains sodium chloride and a solvent. The solvent is composed of 99.9 wt % of ethanol and 0.1 wt % of water. The mass content of sodium chloride in the solvent is 1%.

[0062] The polishing medium for solid electrolytic polishing of titanium or titanium alloy in this example is prepared by the following preparation method:

[0063] Take 20 kg of anhydrous ethanol solution, add a certain amount of sodium hydroxide and 10 kg of air-dried carboxylic acid type acrylic acid ion exchange resin, stir well, filter after the pH stabilizes to 6.5, and dry at room temperature to obtain treated solid particles.

[0064] Then take 19.98 kg of anhydrous ethanol solution, add 200 g of sodium chloride, 20 g of water and the treated solid particles, stir well, filter, and dry at room temperature to obtain the polishing medium of this example.

[0065] In the polishing medium of this example, the content of the electrolyte is 50wt%.

[0066] Example 3

[0067] The electrolyte for solid electrolytic polishing of titanium or titanium alloy in this example contains sodium chloride and a solvent. The solvent is composed of 99.9wt% ethanol and 0.1wt% water. The mass content of sodium chloride in the solvent is 5%.

[0068] The polishing medium for solid electrolytic polishing of titanium or titanium alloy in this example is prepared by the following preparation method:

[0069] Take 20 kg of anhydrous ethanol solution, add a certain amount of sodium hydroxide and 10 kg of air-dried carboxylic acid type acrylic acid ion exchange resin, stir well, filter after the pH stabilizes to 6.5, and dry at room temperature to obtain treated solid particles.

[0070] Then take 19.98 kg of anhydrous ethanol solution, add 1 kg of sodium chloride, 20 g of water and the treated solid particles, stir well, filter, and dry at room temperature to obtain the polishing medium of this example.

[0071] In the polishing medium of this example, the content of the electrolyte is 50wt%.

[0072] Example 4

[0073] The electrolyte for solid electrolytic polishing of titanium or titanium alloy in this example contains sodium chloride and a solvent. The solvent is composed of 99 wt % ethanol and 1 wt % water. The mass content of sodium chloride in the solvent is 0.2%.

[0074] The polishing medium for solid electrolytic polishing of titanium or titanium alloy in this example is prepared by the following preparation method:

[0075] Take 20 kg of anhydrous ethanol solution, add a certain amount of sodium hydroxide and 10 kg of air-dried carboxylic acid type acrylic acid ion exchange resin, stir well, filter after the pH stabilizes to 6.5, and dry at room temperature to obtain treated solid particles.

[0076] Then take 19.8 kg of anhydrous ethanol solution, add 40 g of sodium chloride, 200 g of water and the treated solid particles, stir well, filter, and dry at room temperature to obtain the polishing medium of this example.

[0077] In the polishing medium of this example, the content of the electrolyte is 50wt%.

[0078] Example 5

[0079] The electrolyte for solid electrolytic polishing of titanium or titanium alloy in this example contains sodium sulfate and a solvent. The solvent is composed of 99.9wt% ethanol and 0.1wt% water. The mass content of sodium sulfate in the solvent is 0.2%.

[0080] The polishing medium for solid electrolytic polishing of titanium or titanium alloy in this example is prepared by the following preparation method:

[0081] Take 20 kg of anhydrous ethanol solution, add a certain amount of sodium hydroxide and 10 kg of air-dried carboxylic acid type acrylic acid ion exchange resin, stir well, filter after the pH stabilizes to 6.5, and dry at room temperature to obtain treated solid particles.

[0082] Then take 19.98 kg of anhydrous ethanol solution, add 40 g of sodium sulfate, 20 g of water and the treated solid particles, stir well, filter, and dry at room temperature to obtain the polishing medium of this example.

[0083] In the polishing medium of this example, the content of the electrolyte is 50wt%.

[0084] Comparative Example 1

[0085] The electrolyte for solid electrolytic polishing of titanium or titanium alloy in this example is composed of 99.9wt% ethanol and 0.1wt% water.

[0086] The polishing medium for solid electrolytic polishing of titanium or titanium alloy in this example is prepared by the following preparation method:

[0087] Take 20 kg of anhydrous ethanol solution, add a certain amount of sodium hydroxide and 10 kg of air-dried carboxylic acid type acrylic acid ion exchange resin, stir well, filter after the pH stabilizes to 6.5, and dry at room temperature to obtain treated solid particles.

[0088] Then take 19.98 kg of anhydrous ethanol solution, add 20 g of water and the treated solid particles, stir well, filter, and dry at room temperature to obtain the polishing medium of this example.

[0089] In the polishing medium of this example, the content of the electrolyte is 50wt%.

[0090] Comparative Example 2

[0091] The electrolyte for solid electrolytic polishing of titanium or titanium alloy in this example contains sodium chloride and a solvent, wherein the solvent is ethanol, and the mass content of sodium chloride in the solvent is 0.2%.

[0092] The polishing medium for solid electrolytic polishing of titanium or titanium alloy in this example is prepared by the following preparation method:

[0093] Take 20 kg of anhydrous ethanol solution, add a certain amount of sodium hydroxide and 10 kg of air-dried carboxylic acid type acrylic acid ion exchange resin, stir well, filter after the pH stabilizes to 6.5, and dry at room temperature to obtain treated solid particles.

[0094] Take another 20 kg of anhydrous ethanol solution, add 40 g of sodium chloride and the treated solid particles, stir well, filter, and dry at room temperature to obtain the polishing medium of this example.

[0095] In the polishing medium of this example, the content of the electrolyte is 50wt%.

[0096] Comparative Example 3

[0097] The electrolyte for solid electrolytic polishing of titanium or titanium alloy in this example contains sodium chloride and a solvent. The solvent is composed of 90 wt % of ethanol and 10 wt % of water. The mass content of sodium chloride in the solvent is 0.2%.

[0098] The polishing medium for solid electrolytic polishing of titanium or titanium alloy in this example is prepared by the following preparation method:

[0099] Take 20 kg of anhydrous ethanol solution, add a certain amount of sodium hydroxide and 10 kg of air-dried carboxylic acid type acrylic acid ion exchange resin, stir well, filter after the pH stabilizes to 6.5, and dry at room temperature to obtain treated solid particles.

[0100] Then take 18 kg of anhydrous ethanol solution, add 40 g of sodium chloride, 2 kg of water and the treated solid particles, stir well, filter, and dry at room temperature to obtain the polishing medium of this example.

[0101] In the polishing medium of this example, the content of the electrolyte is 50wt%.

[0102] Comparative Example 4

[0103] On the basis of Example 1, the preparation method of the polishing medium in this example is adjusted. Except for the pretreatment method of the carboxylic acid type acrylic acid ion exchange resin, the rest is the same as Example 1.

[0104] Specifically, the electrolyte for solid electrolytic polishing of titanium or titanium alloy in this example contains sodium chloride and a solvent, wherein the solvent is composed of 99.9wt% ethanol and 0.1wt% water, and the mass content of sodium chloride in the solvent is 0.2%.

[0105] The polishing medium for solid electrolytic polishing of titanium or titanium alloy in this example is prepared by the following preparation method:

[0106] 10 kg of carboxylic acid type acrylic acid ion exchange resin was dried at 110°C.

[0107] Take 19.98 kg of anhydrous ethanol solution, add a certain amount of sodium hydroxide, 40 g of sodium chloride, 20 g of water and dried carboxylic acid type acrylic ion exchange resin, stir well, filter, and dry at room temperature to obtain the polishing medium of this example.

[0108] In the polishing medium of this example, the content of the electrolyte is 50wt%.

[0109] The polishing media of Examples 1 to 5 and Comparative Examples 1 to 4 prepared above were used to carry out solid electrolytic polishing application experiments of titanium alloys. The titanium alloy parts used in the application experiments were all the same, and their surface roughness before polishing was 5.64 μm. The surface roughness is the roughness test result of the surface of the titanium alloy parts using an optical profilometer.

[0110] The method of solid electrolytic polishing of titanium alloy is as follows:

[0111] The titanium alloy piece was connected to the positive electrode of the power supply of the electrochemical polishing device, and the polishing media of Examples 1 to 5 and Comparative Examples 1 to 4 were placed in metal net bags and connected to the negative electrode of the power supply of the electrochemical polishing device. The electrochemical polishing device was powered on for electrolytic polishing. During electrolytic polishing, the titanium alloy piece to be polished and the polishing medium underwent relative friction motion. The applied voltage was 100V, the relative motion rate was 90r / min, and the polishing time was 60min.

[0112] The polishing test results of Examples 1 to 5 and Comparative Examples 1 to 3 are shown in Table 1.

[0113] Table 1 Polishing test results

[0114]

[0115] According to the experimental results in Table 1, it can be seen that:

[0116] 1. It can be seen from Examples 1-3 and Comparative Example 1 that when no sodium chloride is added, the polishing efficiency is very low. However, after adding a certain amount of sodium chloride, the polishing effect can be improved because chlorine has a better etching effect and can enhance conductivity.

[0117] 2. It can be seen from Example 1 and Example 5 that the polishing effect of sodium chloride is better than that of sodium sulfate, because sodium sulfate has no etching effect.

[0118] 3. It can be seen from Example 1, Example 4, Comparative Example 2 and Comparative Example 3 that the content of small molecule alcohol needs to be controlled at a certain level to achieve a better polishing effect. When the content of small molecule alcohol is too small, that is, the water content is too much, it will cause the titanium alloy to turn blue after polishing, as shown in Comparative Example 3; when the solvent is all small molecule alcohol, that is, it does not contain water, it will cause the conductivity to be too low, which will affect the polishing effect and form a gray appearance, as shown in Comparative Example 2. The content of small molecule alcohol in Example 1 and Example 4 is appropriate, so the polishing effect is better.

[0119] The polishing test results of the polishing medium of Comparative Example 4 are as follows: the titanium alloy becomes gray after polishing, and the surface roughness of the titanium alloy after polishing is 4.16 μm. The reason why the polishing effect of Comparative Example 4 is not good is that the carboxylic acid type acrylic acid ion exchange resin after drying is used, and the heating method affects the pore structure of the resin, so the polishing effect is greatly reduced.

[0120] The present invention achieves a good polishing effect by using an electrolyte composed of a certain amount of inorganic salts and solvents for solid electrolytic polishing of titanium metal or titanium alloy. It can fully polish special metal / alloy products such as titanium or titanium alloy in all directions without dead angles, low energy consumption, strong consistency, no need for manual labor, greatly shorten the process, and facilitate automated operation. It has the advantages of fast, low-carbon, environmentally friendly, and high-quality high brightness and low roughness. In addition, the polishing medium of the present invention is a solid particle, which is easy to transport and post-process. After being used for a period of time, this polishing material can be purified and reused by ion exchange and other methods, which can greatly increase the service life and reduce costs. Therefore, the solid electrolytic polishing solution for titanium or titanium alloy provided by the present invention has a very broad market application prospect.

[0121] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A polishing medium for solid electrolytic polishing of titanium or titanium alloy, characterized in that: include: Solid particles, the solid particles having a porous structure and groups capable of adsorbing and complexing metal ions; An electrolyte, wherein the electrolyte is located inside, or inside and on the surface of the solid particles; The electrolyte includes an inorganic salt and a solvent; The solvent includes a polar organic solvent and water; the mass percentage of the polar organic solvent in the solvent is 90.01% to 99.99%; The resistivity of the polar organic solvent is ≤5×10 7 Ω / cm; The polar organic solvent includes at least one of small molecule alcohol, small molecule ketone, dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, dioxane, and ionic liquid; The inorganic salt includes at least one of chloride salt, fluoride salt, sulfate and nitrate.

2. The polishing medium according to claim 1, characterized in that The small molecule alcohol includes at least one of methanol, ethanol, n-propanol, isopropanol, butanol, and butanediol; The small molecule ketone includes at least one of acetone, butanone and cyclohexanone.

3. The polishing medium according to claim 1, characterized in that The mass percentage of the inorganic salt in the solvent is 0.01% to 5%; And / or, the inorganic salt is selected from one of sodium chloride and sodium sulfate or a combination thereof.

4. The polishing medium according to claim 1, characterized in that The mass percentage of the electrolyte in the polishing medium is 30% to 70%.

5. The polishing medium according to claim 1, characterized in that In the solid particulate matter, the group that adsorbs and complexes metal ions includes at least one of a carboxyl group, an amine group, and a hydroxyl group; And / or, the solid particulate matter includes one or more of ion exchange resin, silica gel, and molecular sieve.

6. The method for preparing the polishing medium for solid electrolytic polishing of titanium or titanium alloy according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: soaking the solid particles in a solution containing a pH regulator, stirring, filtering and drying after the pH value stabilizes, to obtain a solid particle intermediate; S2: soaking the solid particle intermediate in an electrolyte containing an inorganic salt and a solvent, stirring, filtering, and drying to obtain the polishing medium for solid electrolytic polishing of titanium or titanium alloy.

7. The preparation method according to claim 6, characterized in that: In the step S1, waiting for the pH value to be stabilized is waiting for the pH value to be stabilized to 5-9.

8. A solid electrolytic polishing method for titanium or titanium alloy, characterized in that: The following steps are involved: 1) placing the polishing medium for solid electrolytic polishing of titanium or titanium alloy according to any one of claims 1 to 5 and the titanium or titanium alloy to be polished in an electrochemical polishing device; Wherein, the polishing medium of the titanium or titanium alloy solid electrolytic polishing is connected to the negative electrode of the power supply of the electrochemical polishing device, and the titanium or titanium alloy to be polished is connected to the positive electrode of the power supply of the electrochemical polishing device; 2) The electrochemical polishing device is powered on to perform electrolytic polishing. During electrolytic polishing, the titanium or titanium alloy to be polished and the polishing medium undergo relative friction movement.

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