Electrochemical polishing solution for bulb tube cathode as well as preparation method and application of electrochemical polishing solution

Abstract

The invention relates to an electrochemical polishing solution for a bulb tube cathode as well as a preparation method and application of the electrochemical polishing solution. The polishing solution comprises the following raw materials: concentrated sulfuric acid, ethylene glycol, glycerol and water; wherein on the basis of the total volume of the concentrated sulfuric acid, the ethylene glycol and the water, the volume content of the concentrated sulfuric acid is 30%-36%, the volume content of the ethylene glycol is 24%-36%, and the balance is water; on the basis of the total volume of the concentrated sulfuric acid, the ethylene glycol and the water, the volume content of the glycerol is 5%-10%. Specific concentrated sulfuric acid, ethylene glycol and glycerol are matched for use according to a specific proportioning relation, so that the polishing solution is more stable and environment-friendly, lower in cost and good in operation environment, the corrosion inhibition capability of nickel in the polishing process is improved, the polishing effect is good, the surface appearance of a polished workpiece is good, and the surface has obvious metallic luster.

Description

Technical Field

[0001] The present application belongs to the field of electrochemistry, and specifically relates to an electrochemical polishing liquid for a tube cathode and a preparation method and application thereof. Background Art

[0002] The tube is mainly composed of a tube core, a tube sleeve, a radiator, insulating oil and some accessories. The tube core is the core component of the tube, which is composed of an anode and a cathode. Since the cathode of the tube is directly exposed to the vacuum field and the internal electric field is high, discharge and sparking are prone to occur at the protrusion of the tip, so the surface of the cathode of the tube must be polished, which not only improves the oxidation resistance of the cathode of the tube, but also removes the tiny burrs on the surface of the cathode of the tube, improves its surface finish, and avoids the occurrence of sparking of vacuum tube devices.

[0003] When the traditional tube cathode is electro-polished, the polishing liquid contains chromium ions. Chromium is a metal element with strong redox ability. It can react chemically with the metal surface during the polishing process to form a dense oxide film on the metal surface, thereby achieving a good polishing effect. However, the polishing speed is fast, the size changes greatly after polishing, and excessive accumulation in the human body has the risk of cancer, which is harmful to the human body.

[0004] Therefore, the traditional technology still needs to be further improved. Summary of the invention

[0005] Based on this, the purpose of this application includes providing an electrochemical polishing liquid for a tube cathode and a preparation method and application thereof.

[0006] The technical solution of this application to solve the above technical problems is as follows:

[0007] The first aspect of the application provides an electrochemical polishing solution, wherein the raw materials of the polishing solution include, by volume percentage: concentrated sulfuric acid, organic alcohol, additives and water;

[0008] Wherein, based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the concentrated sulfuric acid is 30% to 36%, the volume content of the organic alcohol is 24% to 36%, and the balance is water;

[0009] Based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the additive is 5% to 10%, and the additive includes glycerol.

[0010] The electrochemical polishing liquid for the cathode of the tube of the present application includes specific components and their specific ratios, wherein concentrated sulfuric acid can improve the conductivity of the polishing liquid, improve the conductivity of the polishing liquid, improve the dispersion ability and the anode current efficiency, and play a major dissolving role in the polishing process; the molecules of the organic alcohol can form hydrogen bonds and associate to form a mucus film layer on the surface of the workpiece, which slows down the dissolution rate in the depressions and speeds up the dissolution rate in the protrusions; the use of the glycerol additive not only further reduces the roughness of the workpiece after polishing, but also slows down the size change of the cathode of the tube before and after polishing; the specific concentrated sulfuric acid, organic alcohol and glycerol are used in combination in a specific ratio, so that the polishing liquid is more stable and environmentally friendly, with lower cost and good operating environment, and the corrosion inhibition ability of nickel in the polishing process is improved, the polishing effect is good, the surface appearance of the workpiece after polishing is good, and the surface has obvious metallic luster.

[0011] In some of the embodiments, by volume percentage, based on the total volume of the concentrated sulfuric acid, the water and the organic alcohol, the volume content of the concentrated sulfuric acid is 30% to 36%, the volume content of the organic alcohol is 24% to 36%, the volume content of the glycerol is 5% to 7%, and the balance is water.

[0012] In some embodiments, the additive further comprises at least one of citric acid and oxalic acid; and / or

[0013] The organic alcohol includes a polyol;

[0014] Optionally, the polyol includes at least one of ethylene glycol and butanediol.

[0015] In some embodiments, the additive further comprises oxalic acid, and the mass concentration of the oxalic acid is 0.1 g / L to 2 g / L based on the total volume of the concentrated sulfuric acid, the organic alcohol, the water and the glycerol; and / or

[0016] The additive further comprises citric acid, and the mass content of the citric acid is 0.1% to 5% based on the total mass of the concentrated sulfuric acid, the organic alcohol, the water and the glycerol.

[0017] The second aspect of the present application provides a method for preparing the electrochemical polishing solution, comprising the following steps:

[0018] The concentrated sulfuric acid, organic alcohol and additives are mixed to prepare an electrochemical polishing solution;

[0019] Based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the concentrated sulfuric acid is 30% to 36%, the volume content of the organic alcohol is 24% to 36%, and the balance is water; based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the additive is 5% to 10%, and the additive includes glycerol.

[0020] In some embodiments, the mixing comprises the following steps:

[0021] Adding concentrated sulfuric acid to the water to obtain a first mixed solution;

[0022] adding an organic alcohol to the first mixed solution to prepare a second mixed solution;

[0023] adding glycerol to the second mixed solution to prepare an electrochemical polishing solution;

[0024] Adding organic alcohol into the first mixed solution, the temperature of the first mixed solution does not exceed 60°C.

[0025] The polishing liquid is simple to prepare and easy to operate; the prepared polishing liquid is stable and has good polishing effect.

[0026] In a third aspect of the present application, there is provided a method for electrochemical polishing of a nickel material for a tube cathode, comprising the following steps:

[0027] A lead plate is used as a cathode, and a workpiece used for a tube cathode is used as an anode. The anode is immersed in the electrochemical polishing solution or the electrochemical polishing solution prepared by the preparation method of the electrochemical polishing solution to perform an electrochemical polishing treatment.

[0028] In some embodiments, the electrochemical polishing process conditions include: a current density of 32A / dm 2 ~48A / dm 2 The temperature of the polishing liquid is 20℃~35℃, and the time is 1min~4min.

[0029] In some embodiments, the current of the electrochemical polishing is a constant current; and / or

[0030] Before the step of performing electrochemical polishing, the method further includes the following steps:

[0031] The workpiece for the cathode of the bulb is pre-cleaned.

[0032] In some of the embodiments, in the workpiece, the mass fraction of nickel is ≥ 99.6%.

[0033] The above polishing liquid is used for polishing. After polishing, the alloy surface has a good appearance and obvious metallic luster. The roughness is further reduced and the size change of the tube cathode before and after polishing is slowed down. DETAILED DESCRIPTION

[0034] For ease of understanding of the present application, the present application will be described more fully below, and preferred embodiments of the present application are provided. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0035] The implementation of this application is described in detail below in combination with some implementation methods and examples. This example is implemented based on the technical solution of this application, and provides a detailed implementation method and specific operation process, but the protection scope of this application is not limited to the following examples.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0037] the term

[0038] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0039] In the present application, "plurality", "multiple" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0040] In the present application, the terms "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0041] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0042] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical range disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0043] In the present application, the term "room temperature" generally refers to 4°C to 35°C, preferably 20°C±5°C. In some embodiments of the present application, room temperature refers to 20°C to 30°C.

[0044] In this application, unless otherwise specified, the temperature parameter is allowed to be either a constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0045] In this application, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 2~5h means that the units of the left endpoint "2" and the right endpoint "5" are both h (hours).

[0046] The “water” referred to in this application may independently be distilled water, ultrapure water, filtered water, deionized water, etc.

[0047] A rectifier is a device that converts alternating current into direct current. It can be used to power devices and detect radio signals, etc.

[0048] As shown in the background art, in the conventional technology, the polishing liquid uses a mixed system of two acids to polish the workpiece to be polished.

[0049] The applicant has found through a large number of creative experimental studies that, compared with a mixed system of two acids, using an alcohol to replace the acid in conjunction with a glycerol additive can achieve a better polishing effect on the nickel material used for the cathode of the bulb.

[0050] An embodiment of the present application provides an electrochemical polishing liquid for a cathode of a tube, wherein the raw materials of the polishing liquid include: concentrated sulfuric acid, organic alcohol, additives and water;

[0051] Wherein, based on the total volume of the above-mentioned concentrated sulfuric acid, the above-mentioned organic alcohol and the above-mentioned water, the volume content of the above-mentioned concentrated sulfuric acid is 30%~36%, the volume content of the above-mentioned organic alcohol is 24%~36%, and the balance is water; based on the total volume of the above-mentioned concentrated sulfuric acid, the above-mentioned organic alcohol and the above-mentioned water, the volume content of the above-mentioned additives is 5~10%, and the above-mentioned additives include glycerol.

[0052] In some of the embodiments, the mass fraction of sulfuric acid in the concentrated sulfuric acid is 95% to 98%.

[0053] It is understood that when a numerical range is disclosed herein, the above range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0054] It should be noted that the range of concentrated sulfuric acid is "30% to 36%", which means the minimum and maximum values ​​in the range of 30% to 36%, and every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments and the following point values: 30%, 30.1%, 30.2%, 30.3%, 30.4%, 30.5%, 30.6%, 30.7%, 30.8%, 30.9%, 31%, 31.1%, 31.2%, 31.3%, 31.4%, 31.5%, 31.6%, 31.7%, 31.8%, 31.9%, 32%, 32.1%, 32.2%, 32.3%, 32.4%, 32.5%, 32.6%, 32.7%, 32.8%, 32.9%, 33%, 33.1%, 33.2% , 33.3%, 33.4%, 33.5%, 33.6%, 33.7%, 33.8%, 33.9%, 34%, 34.1%, 34.2%, 34.3%, 34.5%, 34.6%, 34.7%, 34.8%, 34.9%, 35%, 35.1%, 35.2%, 35.3%, 35.4%, 35.5%, 35.6%, 35.7%, 35.8%, 35.9% or 36%; or a range consisting of any two of these values, as examples, including: 30% to 35%.

[0055] The value range of organic alcohol is "24%~36%", which means the minimum and maximum values ​​in the range of 24%~36%, and every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments and the following point values: 24%, 24.1%, 24.2%, 24.3%, 24.4%, 24.5%, 24.6%, 24.7%, 24.8%, 24.9%, 25%, 25.1%, 25.2%, 25.3%, 25.4%, 25.5%, 25.6%, 25.7%, 25.8%, 25.9%, 26%, 26.1%, 26.2%, 26.3%, 26.4%, 26.5%, 26.6%, 26.7%, 26.8%, 26.9%, 27.1%, 27.2%, 27.3%, 27.4%, 27.5%, 27.6%, 27.7%, 27.8%, 27.9%, 28.1%, 28.2%, 28.3%, 28.4%, 28.5%, 28.6%, 28.7%, 28.8%, 28.9%, 29. .8%, 26.9%, 27%, 27.1%, 27.2%, 27.3%, 27.4%, 27.5%, 27.6%, 27.7%, 27.8%, 27.9%, 28%, 28.1%, 28.2%, 28.3%, 28.4%, 28.5%, 28.6%, 28.7%, 28.8%, 28.9%, 29%, 29.1%, 29.2%, 29.3%, 29.4%, 29.5%, 29.6%, 29.7%, 29.8%, 29.9%, 30%, 30.1%, 30.2%, 30.3%, 30.4%, 30.5%, 30.6%, 30.7%, 30.8%, 30.9%, 31%, 31.1%, 31.2%, 31.3%, 31.4%, 31.5%, 31.6%, 31.7%, 31.8%, 31.9%, 32%, 32.1%, 32.2%, 32.3%, 32.4%, 32.5%, 32.6%, 32.7%, 32.8%, 32.9%, 33%, 33.1%, 33.2%, 33.3%, 33.4%, 33.6%, 33.7%, 33.8%, 33.9%, 34.1%, 34.2%, 34.3%, 34.4%, 34.5%, 34.6%, 34.7%, 34.8%, 34.9%, 35. 3.3%, 33.4%, 33.5%, 33.6%, 33.7%, 33.8%, 33.9%, 34%, 34.1%, 34.2%, 34.3%, 34.5%, 34.6%, 34.7%, 34.8%, 34.9%, 35%, 35.1%, 35.2%, 35.3%, 35.4%, 35.5%, 35.6%, 35.7%, 35.8%, 35.9% or 36%; or a range consisting of any two of these values, including, by way of example, 24% to 30%.

[0056] The value range of glycerol is "5%~10%", which means that it can take the minimum and maximum values ​​in the range of 5%~10%, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments and the following point values: 5%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9%, 7%, 7.1%, 7.2%, 7.3%, 7.4%, 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, 8%, 8.1%, 8.2%, 8.3%, 8.4%, 8.5%, 8.6%, 8.7%, 8.8%, 8.9%, 9%, 9.1%, 9.2%, 9.3%, 9.4%, 9.5%, 9.6%, 9.7%, 9.8%, 9.9% or 10%; or a range consisting of any two of these values, including, by way of example, 5% to 8%.

[0057] The electrochemical polishing liquid for the cathode of the tube of the present application includes specific components and their specific ratios, wherein concentrated sulfuric acid can improve the conductivity of the polishing liquid, improve the conductivity of the polishing liquid, improve the dispersion ability and the anode current efficiency, and play a major dissolving role in the polishing process; the molecules of the organic alcohol can form hydrogen bonds and associate to form a mucus film layer on the surface of the workpiece, which slows down the dissolution rate in the depressions and speeds up the dissolution rate in the protrusions; the use of the glycerol additive not only further reduces the roughness of the workpiece after polishing, but also slows down the size change of the cathode of the tube before and after polishing; the specific concentrated sulfuric acid, organic alcohol and glycerol are used in combination in a specific ratio, so that the polishing liquid is more stable and environmentally friendly, with lower cost and good operating environment, and the corrosion inhibition ability of nickel in the polishing process is improved, the polishing effect is good, the surface appearance of the workpiece after polishing is good, and the surface has obvious metallic luster.

[0058] In some embodiments, by volume percentage, based on the total volume of the concentrated sulfuric acid, the water and the organic alcohol, the volume content of the concentrated sulfuric acid is 30% to 36%, the volume content of the organic alcohol is 24% to 36%, and the balance is water. Based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the glycerol is 5% to 7%.

[0059] In some of the embodiments, by volume percentage, based on the total volume of the concentrated sulfuric acid, the water and the organic alcohol, the volume content of the concentrated sulfuric acid is 35.9%, the volume content of the water is 28.1%, and the volume content of the organic alcohol is 36%. Based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the glycerol is 6.7%.

[0060] In some embodiments, the additive further includes at least one of citric acid and oxalic acid.

[0061] In some embodiments, the organic alcohol comprises a polyol.

[0062] In some embodiments, the polyol includes at least one of ethylene glycol and butanediol.

[0063] In a specific example, the polyol is ethylene glycol.

[0064] In some embodiments, the additive further includes oxalic acid, and the mass concentration of the oxalic acid is 0.1 g / L to 2 g / L based on the total volume of the concentrated sulfuric acid, the organic alcohol, the water and the glycerol.

[0065] The mass concentration of oxalic acid ranges from "0.1 g / L to 2 g / L", i.e., the minimum and maximum values ​​of the range of 0.1 g / L to 2 g / L, and every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments and the following point values: 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L, 0.5 g / L, 0.6 g / L, 0.7 g / L, 0.8 g / L, 0.9 g / L, 1 g / L, 1.1 g / L, 1.2 g / L, 1.3 g / L, 1.4 g / L, 1.5 g / L, 1.6 g / L, 1.7 g / L, 1.8 g / L, 1.9 g / L or 2 g / L; or a range consisting of any two of these values, for example, including: 0.3 g / L to 1.8 g / L.

[0066] In some embodiments, the additive further comprises citric acid, and the mass content of the citric acid is 0.1% to 5% based on the total mass of the concentrated sulfuric acid, the organic alcohol, the water and the glycerol.

[0067] The value range of citric acid is "0.1%~5%", which means that the minimum and maximum values ​​in the range of 0.1%~5% can be taken, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments and the following point values: 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9% or 5%; or a range composed of any two of these values, as an example, including: 1% to 3%.

[0068] It can be understood that the above additives do not affect the electrochemical reaction balance, but can accelerate the reaction rate.

[0069] Another embodiment of the present application provides a method for preparing the electrochemical polishing solution, comprising the following steps: mixing concentrated sulfuric acid, an organic alcohol and an additive to prepare an electrochemical polishing solution;

[0070] Based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the concentrated sulfuric acid is 30% to 36%, the volume content of the organic alcohol is 24% to 36%, and the balance is water; based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the additive is 5% to 10%, and the additive includes glycerol.

[0071] In some embodiments, the mixing step includes steps S110 to S130.

[0072] Step S110: adding concentrated sulfuric acid into water to obtain a first mixed solution.

[0073] Step S120: adding organic alcohol to the first mixed solution to prepare a second mixed solution.

[0074] Step S130: adding glycerol to the second mixed solution to prepare an electrochemical polishing solution.

[0075] In some embodiments, the mixing sequence between the above steps 110 to S130 is not specific.

[0076] Specifically, step S130 includes step S131 to step S132.

[0077] Step S131: adding glycerol to the second mixed solution to obtain a third mixed solution;

[0078] Step S132: adding the other additives mentioned above into the third mixed solution to prepare an electrochemical polishing solution.

[0079] In some embodiments, an organic alcohol is added to the first mixed solution, and the temperature of the first mixed solution does not exceed 60°C.

[0080] The polishing liquid is simple to prepare, easy to operate and has good polishing effect.

[0081] An embodiment of the present application also provides an electrochemical polishing method for a nickel material used for a bulb cathode, comprising steps S210 to S220.

[0082] Step S210: pre-cleaning the workpiece for the cathode of the bulb to obtain the pre-cleaned workpiece for the cathode of the bulb.

[0083] In some of the embodiments, the pre-cleaning treatment includes rough ultrasonic cleaning and fine ultrasonic cleaning at 50° C. with a neutral degreasing cleaning agent, and rinsing and immersion with ultrapure water to remove oil and dirt from the workpiece used for the cathode of the bulb.

[0084] Step S220: Use the lead plate as the cathode and the workpiece used for the cathode of the bulb as the anode, immerse the anode in the electrochemical polishing solution or the electrochemical polishing solution prepared by the preparation method of the electrochemical polishing solution, and perform electrochemical polishing treatment.

[0085] In some embodiments, the electrochemical polishing process conditions include: a current density of 32A / dm 2 ~48A / dm 2 The temperature of the polishing liquid is 20℃~35℃, and the time is 1min~4min.

[0086] It is understood that when a numerical range is disclosed herein, the above range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0087] It should be noted that the current density range is "32A / dm 2 ~48A / dm 2 "You can get 32A / dm 2 ~48A / dm 2The minimum and maximum values ​​of the range, and every value between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiment and the following point values: 32 A / dm 2 , 32.1 A / dm 2 , 32.2 A / dm 2 , 32.3 A / dm 2 、32.4A / dm 2 , 32.5 A / dm 2 , 32.6 A / dm 2 , 32.7 A / dm 2 , 32.8 A / dm 2 , 32.9 A / dm 2 、33 A / dm 2 , 33.1 A / dm 2 , 33.2 A / dm 2 , 33.3 A / dm 2 、334 A / dm 2 , 33.5 A / dm 2 , 33.6 A / dm 2 , 33.7 A / dm 2 , 33.8 A / dm 2 , 33.9 A / dm 2 , 34 A / dm 2 , 34.1 A / dm 2 , 34.2 A / dm 2 , 34.3 A / dm 2 , 34.4 A / dm 2 、34.5 A / dm 2 、34.6A / dm 2 , 34.7 A / dm 2 、34.8 A / dm 2 , 34.9 A / dm 2 , 35 A / dm 2 , 35.1 A / dm 2 , 35.2 A / dm 2 , 35.3 A / dm 2 , 35.4 A / dm 2 , 35.5 A / dm 2 、35.6 A / dm 2 , 35.7 A / dm 2 , 35.8 A / dm 2 、35.9 A / dm 2 , 36 A / dm 2 , 36.1 A / dm2 、36.2 A / dm 2 、36.3 A / dm 2 、36.4 A / dm 2 、36.5 A / dm 2 、36.6 A / dm 2 、36.7 A / dm 2 、36.8 A / dm 2 、36.9 A / dm 2 、37 A / dm 2 、37.1 A / dm 2 、37.2 A / dm 2 、37.3 A / dm 2 、37.4 A / dm 2 、37.5A / dm 2 、37.6 A / dm 2 、37.7 A / dm 2 、37.8 A / dm 2 、37.9 A / dm 2 、38 A / dm 2 、38.1 A / dm 2 、38.2 A / dm 2 、38.3 A / dm 2 、38.4 A / dm 2 、38.5 A / dm 2 、38.6 A / dm 2 、38.7 A / dm 2 、38.8 A / dm 2 、38.9 A / dm 2 、39 A / dm 2 、39.1 A / dm 2 、39.2 A / dm 2 、39.3 A / dm 2 、39.4 A / dm 2 、39.5 A / dm 2 、39.6 A / dm 2 、39.7 A / dm 2 、39.8 A / dm 2 、39.9 A / dm 2 、40 A / dm 2 、40.1 A / dm 2 、40.2 A / dm 2 、40.3 A / dm 2 、40.4A / dm 2 、40.5 A / dm2 、40.6 A / dm 2 、40.7 A / dm 2 、40.8 A / dm 2 、40.9 A / dm 2 、41 A / dm 2 、41.1 A / dm 2 、41.2 A / dm 2 、41.3 A / dm 2 、41.4 A / dm 2 、41.5 A / dm 2 、41.6 A / dm 2 、41.7 A / dm 2 、41.8 A / dm 2 、41.9 A / dm 2 、42 A / dm 2 、42.1 A / dm 2 、42.2 A / dm 2 、42.3 A / dm 2 、42.4 A / dm 2 、42.5 A / dm 2 、42.6 A / dm 2 、42.7 A / dm 2 、42.8 A / dm 2 、42.9 A / dm 2 、43 A / dm 2 、43.1 A / dm 2 、43.2 A / dm 2 、43.3A / dm 2 、43.4 A / dm 2 、43.5 A / dm 2 、43.6 A / dm 2 、43.7 A / dm 2 、43.8 A / dm 2 、43.9 A / dm 2 、44 A / dm 2 、44.1 A / dm 2 、44.2 A / dm 2 、44.3 A / dm 2 、44.4 A / dm 2 、44.5 A / dm 2 、44.6 A / dm 2 、44.7 A / dm 2 、44.8 A / dm 2 、44.9 A / dm2 , 45 A / dm 2 , 45.1 A / dm 2 , 45.2 A / dm 2 , 45.3 A / dm 2 , 45.4 A / dm 2 , 45.5 A / dm 2 , 45.6 A / dm 2 , 45.7 A / dm 2 , 45.8 A / dm 2 , 45.9 A / dm 2 , 46 A / dm 2 , 46.1 A / dm 2 、46.2A / dm 2 , 46.3 A / dm 2 , 46.4 A / dm 2 , 46.5 A / dm 2 , 46.6 A / dm 2 , 46.7 A / dm 2 , 46.8 A / dm 2 , 46.9 A / dm 2 , 47 A / dm 2 , 47.1 A / dm 2 , 47.2 A / dm 2 , 47.3 A / dm 2 , 47.4 A / dm 2 , 47.5 A / dm 2 , 47.6 A / dm 2 , 47.7 A / dm 2 , 47.8 A / dm 2 , 47.9 A / dm 2 or 48A / dm 2 ; or a range consisting of any two of these values, including, by way of example: 40 A / dm 2 ~48 A / dm 2 .

[0088] The temperature of the polishing liquid ranges from 20°C to 35°C, i.e., the minimum and maximum values ​​in the range of 20°C to 35°C, and every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments and the following point values: 20°C, 20.5°C, 21°C, 21.5°C, 22°C, 22.5°C, 23°C, 23.5°C, 24°C, 24.5°C, 25°C, 25.5°C, 26°C, 26.5°C, 27°C, 27.5°C, 28°C, 28.5°C, 29°C, 29.5°C, 30°C, 30.5°C, 31°C, 31.5°C, 32°C, 32.5°C, 33°C, 33.5°C, 34°C, 34.5°C or 35°C; or a range consisting of any two of these values, including, for example, 20°C to 30°C.

[0089] The range of the polishing time is "1min~4min", which means the minimum and maximum values ​​in the range of 1min~4min, and every value between the minimum and maximum values. Specific examples include but are not limited to the point values ​​in the embodiment and the following point values: 1 min, 1.5 min, 2 min, 2.5 min, 3 min, 3.5 min or 4 min; or a range consisting of any two of these values, including, as an example: 1 min ~3 min.

[0090] It can be understood that the temperature of the above-mentioned polishing liquid is controlled by electric heating. The electric heating is turned on to heat the electro-polishing liquid to a certain temperature, the rectifier is turned on, the current is set to power on, and the electro-polishing starts. After a period of time, the electro-polishing ends.

[0091] In some embodiments, the current of the electrochemical polishing is a constant current.

[0092] It can be understood that the polishing process uses constant current to control the electropolishing reaction process. The current is unstable in the constant voltage mode, which will affect the final polishing result.

[0093] In some of the embodiments, in the workpiece, the mass fraction of nickel is ≥99.6%.

[0094] When the polishing liquid is used for polishing, the alloy surface has a good appearance and obvious metallic luster after polishing, which not only further reduces the roughness, but also slows down the size change of the tube cathode before and after polishing.

[0095] In order to make it easier to understand and implement the present application, the following easier-to-implement, more specific and detailed embodiments and comparative examples are provided as references.

[0096] The following will further illustrate the concept, specific examples and technical effects of the present application in combination with the embodiments to fully understand the present application. The purpose of providing these descriptions is only to help explain the present application and should not be used to limit the scope of the claims of the present application.

[0097] Unless otherwise specified, the raw materials used in the following experiments can be purchased from the market.

[0098] Example 1

[0099] 1. Screening and verification of acid-alcohol system

[0100] First, electrochemical polishing is performed using an acid-alcohol system polishing liquid. The specific polishing steps are: 1. Prepare the polishing liquid according to the ratio; 2. Build an electropolishing platform; 3. Hang the parts to be polished on the anode; 4. Power on; 5. Turn off the power to stop the reaction; 6. Remove the parts; 7. Rinse and soak the parts with water; 8. Dry; 9. Vacuum pack; 10. Store in a nitrogen cabinet. The composition ratio of the polishing liquid and the specific results of the polishing treatment are shown in Table 1.

[0101] The finish and size of the polished workpiece are tested. Specifically, the surface roughness is measured using the SJ-410 surface roughness measuring instrument. The workpiece before polishing is measured using the surface roughness measuring instrument and recorded as R1. After polishing with the above polishing liquid, the polished workpiece is measured and recorded as R2. Polishing rate ΔRa = (R1- R2) / R1 × 100%.

[0102] Table 1

[0103]

[0104] Under the above system, compared with Examples 1~2, Examples 3~9 have some effect on the polishing of the workpiece, but the polishing speed is too fast and the size changes greatly after polishing, which does not meet the polishing requirements of the cathode workpiece of the tube in this case (roughness is less than 0.4 and the size removal is 7µm per side).

[0105] 2. Optimal formula for acid-alcohol system and glycerin

[0106] Additives are further added to the system, which do not affect the balance of the electrochemical reaction, but can slow down the corrosion rate of the workpiece. Different types of additives are added to the above concentrated sulfuric acid-ethylene glycol system (Example 8), based on the total volume of the above concentrated sulfuric acid, the above ethylene glycol and the above water, the volume content of the above glycerol is shown in Table 2, based on the total volume of the above concentrated sulfuric acid, the above ethylene glycol and the above water, the mass concentration of the above oxalic acid is shown in Table 2, based on the total volume of the above concentrated sulfuric acid, the above ethylene glycol and the above water, the mass content of the above citric acid is shown in Table 2, and electrochemical polishing is performed. The specific polishing steps are: 1. Prepare the polishing liquid according to the ratio; 2. Build an electropolishing platform; 3. Hang the parts to be polished on the anode; 4. Power on; 5. Turn off the power to stop the reaction; 6. Remove the parts; 7. Rinse and soak the parts with water; 8. Drying; 9. Vacuum packaging; 10. Store in a nitrogen cabinet.

[0107] The composition ratio of the polishing liquid and the specific results of the polishing treatment are shown in Tables 2 and 3.

[0108] Table 2

[0109]

[0110] Table 3

[0111]

[0112] It can be seen from Tables 2 and 3 that, compared with Example 8, Examples 10-11 and Example 17 add glycerol to the polishing liquid to further reduce the roughness, that is, the polishing effect is good, and slow down the size change of the workpiece before and after polishing; and compared with Examples 10-11, Examples 13-16 and Examples 20-21 show that the addition of citric acid or oxalic acid increases the size reduction while the roughness does not continue to decrease significantly, and the polishing effect of the concentrated sulfuric acid-ethylene glycol system can be maintained.

[0113] 3. Formula of concentrated sulfuric acid-ethylene glycol synergistic with glycerol

[0114] Glycerol was added to the concentrated sulfuric acid-ethylene glycol system, and the total volume of the concentrated sulfuric acid, the water and the ethylene glycol was used as a reference, and the volume content of the glycerol was as shown in Table 4, and electrochemical polishing was performed. The specific polishing steps were: 1. polishing liquid was prepared according to the ratio; 2. an electropolishing platform was built; 3. parts to be polished were hung on the anode; 4. power was turned on; 5. the power was turned off to stop the reaction; 6. parts were removed; 7. parts were rinsed and soaked with water; 8. drying was performed; 9. vacuum packaging was performed; and 10. nitrogen cabinet storage was performed.

[0115] The composition ratio of the polishing liquid and the specific results of the polishing treatment are shown in Table 4.

[0116] Table 4

[0117]

[0118] 4. Electrochemical polishing method of tube cathode workpiece

[0119] 4.1 Steps for preparing electrochemical polishing solution: first prepare water, concentrated sulfuric acid and ethylene glycol into a mixed solution (note that heat will be released when preparing the solution, and the solution temperature does not exceed 60°C when ethylene glycol is present), and then add glycerol; stir the polishing solution thoroughly for 10 minutes to mix evenly; wherein the raw materials of the above-mentioned polishing solution include: concentrated sulfuric acid, ethylene glycol, water and glycerol, calculated by volume percentage, based on the volume of the above-mentioned concentrated sulfuric acid, the above-mentioned ethylene glycol and the above-mentioned water, the concentrated sulfuric acid is 35.9%, the water is 28.1% and the ethylene glycol is 36%; based on the volume of the above-mentioned concentrated sulfuric acid, the above-mentioned ethylene glycol and the above-mentioned water, the volume content of the above-mentioned glycerol is 6.7%; stir the polishing solution thoroughly for 10 minutes to mix evenly for use.

[0120] 4.2 The steps of electrochemical polishing are as follows:

[0121] 1) Degreasing and cleaning of the nickel parts to be polished; the specific steps are: ultrasonic rough cleaning and ultrasonic fine cleaning at 50°C with a neutral degreasing cleaning agent, and rinsing and immersion cleaning with ultrapure water.

[0122] 2) The nickel parts to be polished are compatible with the tooling;

[0123] 3) Build an electropolishing device: Use a lead plate as the electropolishing cathode, and the nickel-polished part as the electropolishing anode. Connect the positive pole of the rectifier to the electropolishing anode, and the negative pole of the rectifier to the electropolishing cathode. Completely immerse the anode part in the electrochemical polishing liquid. Place the anode and cathode in parallel. Turn on the rectifier. The current density is 32-48A / dm2. The temperature of the polishing liquid is controlled at 20-35℃ (turn on electric heating when it is not room temperature). The polishing time is 1-4min. The polishing process uses constant current to control the electropolishing reaction process. The current is unstable in the constant voltage mode, which will affect the final polishing result.

[0124] 4) After polishing, rinse the surface of the nickel part and vacuum dry it.

[0125] In summary, the polishing effect of the workpiece using the electrochemical polishing liquid compound according to the technical solution in claim 1 of the present application is good. The surface appearance of the nickel part after polishing is good and the surface has obvious metallic luster. The polishing process not only further reduces the roughness, but also slows down the dimensional change of the tube cathode before and after polishing.

[0126] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims, and the description may be used to interpret the content of the claims.

Claims

1. An electrochemical polishing solution for a tube cathode, characterized in that: Measured by volume percentage, the raw materials of the polishing liquid include: concentrated sulfuric acid, organic alcohol, additives and water; Wherein, based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the concentrated sulfuric acid is 30% to 36%, the volume content of the organic alcohol is 24% to 36%, and the balance is water; Based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the additive is 5% to 10%, and the additive includes glycerol.

2. The electrochemical polishing liquid for the cathode of the tube according to claim 1, characterized in that: Calculated by volume percentage, based on the total volume of the concentrated sulfuric acid, the water and the organic alcohol, the volume content of the concentrated sulfuric acid is 30% to 36%, the volume content of the organic alcohol is 24% to 36%, the volume content of the glycerol is 5% to 7%, and the balance is water.

3. The electrochemical polishing liquid for a tube cathode according to any one of claims 1 to 2, characterized in that: The additive further comprises at least one of citric acid and oxalic acid; and / or The organic alcohol includes a polyol; Optionally, the polyol includes at least one of ethylene glycol and butanediol.

4. The electrochemical polishing liquid for the cathode of the tube according to claim 3, characterized in that: The additive further comprises oxalic acid, and the mass concentration of the oxalic acid is 0.1 g / L to 2 g / L based on the total volume of the concentrated sulfuric acid, the organic alcohol, the water and the glycerol; and / or The additive further comprises citric acid, and the mass content of the citric acid is 0.1% to 5% based on the total mass of the concentrated sulfuric acid, the organic alcohol, the water and the glycerol.

5. A method for preparing an electrochemical polishing solution, characterized in that: The following steps are involved: The concentrated sulfuric acid, organic alcohol and additives are mixed to prepare an electrochemical polishing solution; Based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the concentrated sulfuric acid is 30% to 36%, the volume content of the organic alcohol is 24% to 36%, and the balance is water; based on the total volume of the concentrated sulfuric acid, the organic alcohol and the water, the volume content of the additive is 5% to 10%, and the additive includes glycerol.

6. The method for preparing an electrochemical polishing solution according to claim 5, characterized in that: The mixing comprises the following steps: Adding concentrated sulfuric acid to the water to obtain a first mixed solution; adding an organic alcohol to the first mixed solution to prepare a second mixed solution; adding glycerol to the second mixed solution to prepare an electrochemical polishing solution; Adding organic alcohol into the first mixed solution, the temperature of the first mixed solution does not exceed 60°C.

7. A method for electrochemical polishing of nickel material for a tube cathode, characterized in that: The following steps are involved: A lead plate is used as a cathode and a workpiece used for a tube cathode is used as an anode. The anode is immersed in an electrochemical polishing liquid as described in any one of claims 1 to 4 or an electrochemical polishing liquid prepared by the preparation method of the electrochemical polishing liquid as described in any one of claims 5 to 6 to perform an electrochemical polishing treatment.

8. The electrochemical polishing method for nickel material used for the cathode of the bulb according to claim 7, characterized in that: The electrochemical polishing treatment conditions include: a current density of 32A / dm 2 ~48A / dm 2 The temperature of the polishing liquid is 20℃~35℃, and the time is 1min~4min.

9. The electrochemical polishing method for nickel material used for a tube cathode according to any one of claims 7 to 8, characterized in that: The current of the electrochemical polishing is a constant current; and / or Before the step of performing electrochemical polishing, the method further includes the following steps: The workpiece for the cathode of the bulb is pre-cleaned.

10. The electrochemical polishing method for nickel material used for a tube cathode according to any one of claims 7 to 8, characterized in that: In the workpiece, the mass fraction of nickel is ≥99.6%.

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