Magnetic field enhanced electrolytic plasma titanium alloy polishing method for improving uniformity

Abstract

The invention discloses a method for polishing titanium alloy through magnetic field enhanced electrolytic plasmas for improving uniformity, and belongs to the technical field of metal material surface treatment. The magnetic field enhanced electrolytic plasma titanium alloy polishing method for improving the uniformity comprises the following steps that a magnetic field with the strength being 0.1-0.5 T is applied while electrolytic plasma polishing is conducted on titanium alloy, and polishing of the titanium alloy is achieved; a polishing solution used for electrolytic plasma polishing is a mixed aqueous solution of ammonium fluoride and potassium fluoride; in the mixed aqueous solution, the concentration of ammonium fluoride is 3-18 g / L, and the concentration of potassium fluoride is 25-100 g / L. According to the method, the movement behavior of the electrolytic plasma is guided through the magnetic field, so that fluorine ions and hydroxyl radicals are distributed on the surface of the electrode in a concentrated manner, the uniformity of chemical reaction is optimized, the consistency of material removal is improved, and the phenomenon of local over-polishing or under-polishing is reduced. And the quality of the titanium alloy polished surface is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal material surface treatment, and more specifically relates to a method for enhancing the electrolytic plasma polishing of titanium alloy with magnetic field to improve uniformity. Background Art

[0002] Electrolytic plasma polishing (EPP) is an innovative metal surface treatment method widely used in the processing of complex-shaped parts, with the advantages of high efficiency and environmental protection. It combines the plasma physics of gas breakdown and ionization and the electrode surface process in electrochemical reactions. Through external circuit regulation, the electric field characteristics between the anode and cathode are formed, thereby generating an air-gap film on the electrode surface. When electrons pass through this air-gap film, the plasma discharge acts in combination with the electrochemical reaction to micro-flatten the metal surface. This technology was first proposed by Duradzhi in 1979 and quickly triggered global research. With the continuous development of the technology, EPP has gradually expanded the range of materials that can be processed, and has been significantly applied in fields such as aerospace, medical, and automotive manufacturing. Titanium and its alloys have become important application objects of EPP technology due to their excellent mechanical properties and biocompatibility.

[0003] The research on electrolytic plasma technology and materials is relatively extensive. The electrolytic plasma polishing technology is a precision machining method that processes the metal surface through plasma discharge in an electrolyte solution to improve the surface finish. Compared with traditional mechanical polishing, this method has higher efficiency and better surface finish. However, in the existing electrolytic plasma polishing system during use, the stability and discharge intensity of the plasma are limited by the electric field strength and the properties of the electrolyte, especially when processing workpieces with high hardness or special shapes, it is difficult to ensure the uniformity and efficiency of the polishing effect. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for enhancing the electrolytic plasma polishing of titanium alloy with magnetic field to improve uniformity, so as to solve the problems existing in the above-mentioned prior art and improve the uniformity and efficiency of the polishing effect when processing workpieces with high hardness or special shapes.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention: Provide a method for enhancing the electrolytic plasma polishing of titanium alloy with magnetic field to improve uniformity, including the following steps:

[0007] While performing electrolytic plasma polishing on the titanium alloy, apply a magnetic field with an intensity of 0.1 - 0.5 T to achieve the polishing of the titanium alloy;

[0008] The polishing liquid used in the electrolytic plasma polishing is an aqueous solution mixture of ammonium fluoride and potassium fluoride; in the aqueous solution mixture, the concentration of ammonium fluoride is 3 to 18 g / L, and the concentration of potassium fluoride is 25 to 100 g / L.

[0009] The present invention uses an aqueous solution mixture of ammonium fluoride and potassium fluoride as the polishing liquid. Combining with the action of a magnetic field, the active components of the polishing liquid can effectively promote the chemical reaction on the surface of the titanium alloy under the action of the magnetic field, improving the polishing effect. The present invention guides the movement behavior of the electrolytic plasma through the magnetic field, making the distribution of fluoride ions and hydroxyl radicals concentrated on the electrode surface, thereby optimizing the uniformity of the chemical reaction, enhancing the consistency of material removal, and reducing the phenomenon of local over-polishing or under-polishing. The action of this external magnetic field effectively optimizes the plasma discharge region, and further improves the quality of the polished surface of the titanium alloy.

[0010] In addition, the magnetic field strength in the present invention is controlled at 0.1 to 0.5 T. Under the action of the magnetic field at this intensity, the movement directions of fluoride ions and hydroxyl radicals can be guided to make them more concentrated on the surface of the titanium alloy. It effectively promotes the uniformity of the chemical reaction, thereby further enhancing the uniformity and consistency of polishing.

[0011] Furthermore, the acting direction of the magnetic field is adjusted according to the processing requirements of the titanium alloy.

[0012] Preferably, it also includes electrolytic plasma polishing by heating the polishing liquid to 60 to 100 °C. Electrolytic plasma polishing at this temperature can enhance the stability and uniformity of the chemical reaction on the surface of the titanium alloy, thereby improving the polishing effect.

[0013] Preferably, the anode of the electrolytic plasma polishing is the titanium alloy, and the cathode is a conductive metal.

[0014] Furthermore, the conductive metal includes stainless steel.

[0015] Preferably, the voltage of the electrolytic plasma polishing is 200 to 600 V. Effective surface treatment of the titanium alloy can be achieved at this voltage, improving the polishing effect of the titanium alloy.

[0016] Preferably, before electrolytic plasma polishing of the titanium alloy, it also includes a step of pre-treating the titanium alloy.

[0017] Preferably, the pre-treatment includes: mechanical grinding and surface impurity removal of the titanium alloy.

[0018] Furthermore, the specific steps of the pre-treatment are:

[0019] (1) Mechanical grinding: The surface of the titanium alloy was ground step by step using 120-mesh, 240-mesh, and 600-mesh sandpapers to remove large-particle surface impurities and lay the foundation for subsequent polishing treatment;

[0020] (2) Ultrasonic cleaning: The titanium alloy after mechanical grinding was ultrasonically cleaned with water to remove impurities generated during the grinding process, and then cleaned with ethanol to remove surface oil stains to ensure the cleanliness of the titanium alloy surface.

[0021] The second technical solution of the present invention: A method for improving the polishing uniformity and efficiency of titanium alloy workpieces with complex shapes is provided. The above-mentioned method of magnetic field-enhanced electrolytic plasma polishing of titanium alloy for improving uniformity is used to polish the titanium alloy workpieces with complex shapes.

[0022] The present invention discloses the following technical effects:

[0023] The magnetic field-enhanced electrolytic plasma polishing method of the present invention is particularly suitable for the high-efficiency precision polishing of titanium alloy workpieces with complex shapes. By optimizing the uniformity of electrolytic plasma polishing, the surface roughness can be effectively reduced, the surface quality can be significantly improved, and the problem of insufficient uniformity existing in traditional electrolytic plasma polishing is solved, having strong industrial application prospects. Description of the Drawings

[0024] Figure 1 Magnetic field-enhanced electrolytic plasma device diagram used for implementing the method of magnetic field-enhanced electrolytic plasma polishing of titanium alloy for improving uniformity;

[0025] Figure 2 Surface morphology diagram of the titanium alloy polished by the methods described in Example 1 and Comparative Example 1;

[0026] Figure 3 Three-dimensional surface morphology diagram of the titanium alloy polished by the methods described in Example 1 and Comparative Example 1;

[0027] Figure 4 SEM diagram of the titanium alloy polished by the methods described in Example 1 and Comparative Example 1;

[0028] Figure 5 Surface morphology diagram of the titanium alloy polished by mechanical grinding in Example 1 and the method described in Comparative Example 2;

[0029] Figure 6 Three-dimensional surface morphology diagram of the titanium alloy polished by mechanical grinding in Example 1 and the method described in Comparative Example 2. Detailed Description of the Invention

[0030] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and implementation manners of the present invention.

[0031] It should be understood that the terms used in the present invention are only for describing particular embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0032] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0033] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the present invention specification, which are obvious to those skilled in the art. Other implementation manners obtained from the present invention specification are also obvious to those skilled in the art. The present invention specification and examples are merely exemplary.

[0034] Regarding "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0035] It should be noted that the parts not described in detail in the present invention are all conventional operation means in the art and are not the focus of the present invention.

[0036] The research on electrolytic plasma technology and materials is relatively extensive. Electrolytic plasma polishing is a new type of special metal surface processing method with high precision, high efficiency, and environmental friendliness. This technology can achieve high-precision and high-efficiency polishing of workpieces with complex shapes and structures. Moreover, the polishing solution is a low-concentration inorganic salt aqueous solution, which greatly reduces the processing cost. The polishing process is environmentally friendly, eliminating noise pollution and dust pollution, and can effectively solve the related problems brought by traditional processing methods. There are various existing methods for polishing titanium alloys with complex shapes. For example, the electrolyte plasma polishing method for titanium alloy femoral stem prostheses can efficiently and environmentally achieve low-cost polishing of the surface of prostheses with complex shapes and structures, showing good industrial application prospects. Another example is the electrolyte plasma polishing technology applicable to pure titanium denture frameworks. By using a low-concentration inorganic salt aqueous solution as the polishing solution, it not only reduces environmental pollution but also achieves high-efficiency polishing of complex structures. In addition, there is a method of reducing the surface roughness by treating diesel engine components in an electrolyte plasma polishing bath, thereby improving the surface quality of the components. The above-mentioned technologies demonstrate the extensive application and significant advantages of electrolyte plasma polishing in different fields. However, during the use of existing electrolyte plasma polishing systems, the stability and discharge intensity of the plasma are limited by the electric field strength and the properties of the electrolyte, especially when processing workpieces with high hardness or special shapes, it is difficult to ensure the uniformity and efficiency of the polishing effect.

[0037] Based on the above defects existing in the prior art, the present invention provides a method for magnetic field-enhanced electrolytic plasma polishing of titanium alloys to improve uniformity. This method combines the selection of a specific polishing solution with the action of a magnetic field. By guiding the movement behavior of the electrolytic plasma through the magnetic field, the distribution of fluoride ions and hydroxyl radicals is concentrated on the electrode surface, thereby optimizing the uniformity of the chemical reaction, improving the consistency of material removal, and reducing the phenomenon of local over-polishing or under-polishing. The action of this external magnetic field effectively optimizes the plasma discharge region, and further improves the surface quality of the titanium alloy, solving the problems existing in the above-mentioned prior art.

[0038] Unless otherwise specified, the raw materials used in the following examples and comparative examples of the present invention are commercially available products, and the sources of the commercially available products do not affect the technical effects of the present invention.

[0039] Example 1

[0040] This example provides a method for magnetic field-enhanced electrolytic plasma polishing of titanium alloys to improve uniformity. The specific steps are as follows:

[0041] (1) Mechanical grinding: The cast titanium alloy workpiece is ground step by step with 120-mesh, 240-mesh, and 600-mesh sandpapers. By step-by-step grinding, large particle impurities on the surface are removed.

[0042] (2) Ultrasonic cleaning: Place the ground titanium alloy workpiece in a beaker containing 200 mL of deionized water and ultrasonically clean it for 10 min to remove surface impurities after grinding; then place it in a beaker containing 200 mL of absolute ethanol and ultrasonically clean it for 10 min to remove surface oil stains.

[0043] (3) Electrolytic plasma polishing electrode setting: Connect the cleaned titanium alloy as the anode to the positive pole of the power supply, and connect the stainless steel material as the cathode to the negative pole of the power supply. The size of the processed titanium alloy workpiece is 15×20×3 mm, and the area of the used stainless steel cathode material is 10 - 20 times that of the surface area of the titanium alloy to ensure sufficient current flow and form a uniform electrolytic plasma.

[0044] (4) Electrolytic plasma polishing voltage setting: In this step, the titanium alloy is connected as the anode to the positive pole of the power supply, and the stainless steel is connected as the cathode to the negative pole of the power supply, and the power supply voltage is adjusted to 350 V.

[0045] (5) Electrolytic plasma polishing solution component and concentration setting: Use a mixed aqueous solution of ammonium fluoride and potassium fluoride dihydrate as the polishing solution. Among them, the concentration of ammonium fluoride is 18 g / L, and the concentration of potassium fluoride dihydrate is 100 g / L.

[0046] (6) Electrolytic plasma polishing solution temperature setting: Heat the polishing solution to 80 °C and use a temperature sensor for real-time monitoring. Ensure that the temperature of the polishing solution is maintained within an appropriate range to optimize the efficiency and uniformity of the polishing reaction.

[0047] (7) Magnetic field enhanced electrolytic plasma polishing setting: Use Figure 1 the electromagnetic coil in

[0048] Example 2

[0049] A method for magnetic field enhanced electrolytic plasma polishing of titanium alloy to improve uniformity, comprising the following steps:

[0050] (1) Mechanical grinding: Gradually grind the cast titanium alloy workpiece with 120-mesh, 240-mesh, and 600-mesh sandpapers. By gradually grinding, remove large particle impurities on the surface.

[0051] (2) Ultrasonic cleaning: Place the ground titanium alloy workpiece in a beaker containing 200 mL of deionized water and ultrasonically clean it for 10 min to remove surface impurities after grinding; then place it in a beaker containing 200 mL of absolute ethanol and ultrasonically clean it for 10 min to remove surface oil stains.

[0052] (3) Electrolytic plasma polishing electrode setting: The cleaned titanium alloy is used as the anode and connected to the positive pole of the power supply, and the stainless steel material is used as the cathode and connected to the negative pole of the power supply. The size of the processed titanium alloy workpiece is 15×20×3 mm, and the area of the used stainless steel cathode material is 10 - 20 times that of the surface area of the titanium alloy, ensuring sufficient current flow and forming a uniform electrolytic plasma.

[0053] (4) Electrolytic plasma polishing voltage setting: In this step, the titanium alloy is used as the anode and connected to the positive pole of the power supply, and the stainless steel is used as the cathode and connected to the negative pole of the power supply. The power supply voltage is adjusted to 300 V.

[0054] (5) Electrolytic plasma polishing solution component and concentration setting: A mixed aqueous solution of ammonium fluoride and potassium fluoride dihydrate is used as the polishing solution. Among them, the concentration of ammonium fluoride is 15 g / L, and the concentration of potassium fluoride dihydrate is 90 g / L.

[0055] (6) Electrolytic plasma polishing solution temperature setting: The polishing solution is heated to 100 °C and monitored in real time using a temperature sensor. Ensure that the temperature of the polishing solution is maintained within an appropriate range to optimize the efficiency and uniformity of the polishing reaction.

[0056] (7) Magnetic field enhanced electrolytic plasma polishing setting: Use Figure 1 the electromagnetic coil in

[0057] Example 3

[0058] A method for magnetic field enhanced electrolytic plasma polishing of titanium alloy to improve uniformity, comprising the following steps:

[0059] (1) Mechanical grinding: The cast titanium alloy is ground step by step using sandpapers of 120 mesh, 240 mesh, and 600 mesh. By step-by-step grinding, large particle impurities on the surface are removed.

[0060] (2) Ultrasonic cleaning: The ground titanium alloy sample is placed in a beaker containing 150 mL of deionized water and ultrasonically cleaned for 10 min to remove surface impurities after grinding; then it is placed in a beaker containing 150 mL of absolute ethanol and ultrasonically cleaned for 10 min to remove surface oil stains.

[0061] (3) Electrolytic plasma polishing electrode setting: The cleaned titanium alloy is used as the anode and connected to the positive pole of the power supply, and the stainless steel material is used as the cathode and connected to the negative pole of the power supply. The size of the processed titanium alloy workpiece is 15×20×3 mm, and the area of the used stainless steel cathode material is 10 - 20 times that of the surface area of the titanium alloy, ensuring sufficient current flow and forming a uniform electrolytic plasma.

[0062] (4) Electrolytic plasma polishing voltage setting: In this step, the titanium alloy is connected to the positive electrode of the power supply as the anode, and the stainless steel is connected to the negative electrode of the power supply as the cathode. The power supply voltage is adjusted to 400V.

[0063] (5) Electrolytic plasma polishing solution composition and concentration setting: A mixed aqueous solution of ammonium fluoride and potassium fluoride dihydrate is used as the polishing solution. Among them, the concentration of ammonium fluoride is 10g / L, and the concentration of potassium fluoride dihydrate is 100g / L.

[0064] (6) Electrolytic plasma polishing solution temperature setting: The polishing solution is heated to 85°C and monitored in real time using a temperature sensor. Ensure that the temperature of the polishing solution is maintained within an appropriate range to optimize the efficiency and uniformity of the polishing reaction.

[0065] (7) Magnetic field enhanced electrolytic plasma polishing setting: Use Figure 1 the electromagnetic coil in it to generate an adjustable magnetic field. The magnetic induction intensity is 0.35T, and the magnetic field direction is perpendicular to the surface of the titanium alloy workpiece. In this way, the polishing of the titanium alloy workpiece is realized.

[0066] Comparative Example 1

[0067] The difference from Example 1 is that the setting of the magnetic field is omitted, and the others are the same as Example 1.

[0068] Figure 2 Figure shows the surface morphology of the titanium alloy polished by the methods described in Example 1 and Comparative Example 1. The results show that there are still scratches and holes that have not been removed on the surface after electrolytic plasma polishing, while the surface of the titanium alloy workpiece is flat and smooth after the magnetic field enhanced electrolytic plasma polishing described in the present invention.

[0069] Figure 3 Figure shows the three-dimensional surface morphology of the titanium alloy polished by the methods described in Example 1 and Comparative Example 1. The results show that the maximum roughness of electrolytic plasma polishing is 35μm, while the maximum roughness of the magnetic field enhanced electrolytic plasma polishing described in the present invention is only 5μm, and the roughness is significantly reduced.

[0070] Figure 4 Figure shows the SEM image of the titanium alloy polished by the methods described in Example 1 and Comparative Example 1. The results show that there are still pits that have not been removed on the surface after electrolytic plasma polishing, while the overall discharge on the surface of the titanium alloy workpiece is more uniform after the magnetic field enhanced electrolytic plasma polishing described in the present invention.

[0071] Comparative Example 2

[0072] The difference from Example 1 is that the polishing solution is composed of 30g potassium chloride, 10g oxalic acid and 1000mL water, and the others are the same as Example 1.

[0073] Figure 5The surface topography of the titanium alloy after mechanical grinding in Example 1 and polishing by the method described in Comparative Example 2. The results show that the polishing liquid in Comparative Example 2 caused corrosion pits on the surface and did not achieve the polishing effect.

[0074] Figure 6 The three-dimensional surface topography of the titanium alloy after mechanical grinding in Example 1 and polishing by the method described in Comparative Example 2. The results show that the surface roughness of the titanium alloy after mechanical grinding is 6.59 μm, and the surface roughness of the titanium alloy polished by the method described in Comparative Example 2 is 8.78 μm. The roughness increases and the surface protrusions are not removed.

[0075] Figure 1 The magnetic field enhanced electrolytic plasma device diagram for the method of magnetic field enhanced electrolytic plasma polishing of titanium alloy for improving uniformity. It includes a magnetic field generating device and an electrolytic plasma polishing device. The magnetic field generating device includes a pair of opposed electromagnets whose magnetic field intensity is controlled by an input power supply; the electrolytic plasma polishing device includes a titanium alloy workpiece anode, a stainless steel cathode and an electrolytic cell.

[0076] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0077] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for polishing titanium alloy by magnetic field enhanced electrolytic plasma to improve uniformity, characterized in that: The steps include: While electrolytic plasma polishing the titanium alloy, a magnetic field with a strength of 0.1 to 0.5 T is applied to achieve polishing of the titanium alloy; The polishing liquid used in the electrolytic plasma polishing is a mixed aqueous solution of ammonium fluoride and potassium fluoride; in the mixed aqueous solution, the concentration of ammonium fluoride is 3-18 g / L, and the concentration of potassium fluoride is 25-100 g / L.

2. The method for polishing titanium alloy by magnetic field enhanced electrolytic plasma for improving uniformity according to claim 1, characterized in that: The method also includes heating the polishing liquid to 60-100° C. to perform electrolytic plasma polishing.

3. The method for polishing titanium alloy by magnetic field enhanced electrolytic plasma for improving uniformity according to claim 1, characterized in that: The anode of the electrolytic plasma polishing is a titanium alloy, and the cathode is a conductive metal.

4. The method for polishing titanium alloy by magnetic field enhanced electrolytic plasma for improving uniformity according to claim 1, characterized in that: The voltage of the electrolytic plasma polishing is 200-600V.

5. The method for polishing titanium alloy by magnetic field enhanced electrolytic plasma for improving uniformity according to claim 1, characterized in that: Before electrolytic plasma polishing of the titanium alloy, the method also includes a step of pre-treating the titanium alloy.

6. The method for polishing titanium alloy by magnetic field enhanced electrolytic plasma for improving uniformity according to claim 5, characterized in that: The pre-treatment includes: mechanical grinding and surface impurity removal of the titanium alloy.

7. A method for improving the polishing uniformity and efficiency of complex-shaped titanium alloy workpieces, characterized in that: The method for polishing titanium alloy with magnetic field enhanced electrolytic plasma for improving uniformity as claimed in any one of claims 1 to 6 is used to polish titanium alloy workpieces with complex shapes.

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