Electroplating solution and preparation method thereof
Patent Information
- Application Number
- TW114106777
- Authority / Receiving Office
- TW · TW
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-02-24
- Publication Date
- 2026-09-01
- Estimated Expiration
- 2045-02-23
AI Technical Summary
Cyanide-based electroplating solutions are highly toxic and contribute to significant environmental pollution, necessitating costly and complex wastewater treatment processes to ensure worker safety and ecological protection.
A non-toxic electroplating solution composed of choline chloride, urea, and cobalt chloride is used, forming a cobalt oxide film on the workpiece surface, which is environmentally friendly and does not require strong acids, with a molar concentration ratio of choline chloride to urea at 1:2 and cobalt chloride at 0.3M.
The solution prevents surface rusting while maintaining a metallic texture and luster, reducing environmental impact by eliminating toxic pollutants and avoiding the need for harsh chemical treatments.
Smart Images
Figure TWG2TA001073918_001 
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Abstract
Description
Technical Field
[0001] This invention relates to the technical field of electroplating solutions, and more particularly to a pollution-free electroplating solution and its preparation method. Prior Technology
[0002] As consumer electronics have evolved, consumers now consider aesthetics as well as functionality when making purchasing decisions. Most consumer electronics on the market today have casings made of metals such as aluminum alloy or aluminum-magnesium alloy. To achieve a decorative effect, the casings of electronic products such as mobile phones, computers, and digital cameras often undergo surface treatment. Among these, products treated with electroplating have a superior metallic texture and better wear resistance.
[0003] Electroplating is a common surface treatment method. The product to be electroplated is placed in an electroplating tank containing a chemical electroplating solution, and an electroplating layer is formed on the surface of the product using the principle of electrolysis. This prevents metal oxidation (such as rust) and creates a visually appealing effect on the metal product. However, pollutants generated during the electroplating process, such as ineffective (active) electroplating solutions, surface impurities, and metal deposits, can become a significant source of water pollution and severely harm the surrounding environment if not properly recycled and treated. Therefore, electroplating plants must first chemically neutralize the wastewater generated after electroplating before discharging it into a sludge tank for sedimentation and then undergo environmentally friendly recycling treatment.
[0004] Specifically, electroplating solutions can be broadly classified into two types: cyanide-based and non-cyanide-based. Due to their superior stability, cyanide-based electroplating solutions are the mainstream technology used in traditional industries. However, this method has a major drawback: cyanide-containing electroplating solutions are highly toxic. Therefore, electroplating workplaces must meet safety standards and have comprehensive wastewater treatment procedures to ensure the health of workers and prevent pollution of the working and ecological environments. The environmental hazards caused by electroplating are primarily due to the electroplating solutions themselves. These solutions contain heavy metals such as nickel, copper, and chromium, while the pre-plating processes involve strong acids and corrosive solutions like sulfuric acid and hydrochloric acid, all of which contribute to water and soil pollution. With increasing environmental awareness, the treatment of electroplating wastewater has become an urgent problem to solve. Summary of the Invention
[0005] In view of the shortcomings of the prior art, the main purpose of this invention is to provide an environmentally friendly and pollution-free electroplating solution. The composition of the electroplating solution is non-toxic and the inorganic acid used is weakly acidic, which is relatively friendly to the working environment and ecological environment and will not cause pollution.
[0006] Another objective of this invention is that the metal coating formed by the pollution-free electroplating solution of this invention can prevent the surface of the workpiece from rusting, while retaining the metallic texture and luster. The composition of the electroplating solution is environmentally friendly and non-toxic, and will not cause toxic pollution to the environment.
[0007] In accordance with the above objectives, the present invention discloses an electroplating solution suitable for electroplating processes. The electroplating solution comprises choline chloride, urea, and cobalt chloride, wherein the molar concentration ratio of choline chloride to urea is 1:2, and the molar concentration of cobalt chloride is 0.3M.
[0008] In accordance with the above objectives, the present invention also discloses an oxide coating formed using an electroplating solution, wherein the oxide coating is deposited on the surface of the workpiece to be electroplated, and the oxide coating is a cobalt oxide film.
[0009] The present invention also discloses a method for preparing an electroplating solution, comprising: mixing choline chloride and urea to form a first mixed solution, wherein the molar concentration ratio of choline chloride to urea is 1:2; and adding cobalt chloride to the first mixed solution to form an electroplating solution, wherein the molar concentration of cobalt chloride added to the first mixed solution is 0.3M. Simple Explanation of the Diagram
[0010] Figure 1 is a flowchart illustrating an embodiment of the method for preparing the electroplating solution of the present invention, based on the technology disclosed herein. Figure 2 is a schematic diagram of the electroplating equipment used in the pollution-free electroplating solution of the present invention, according to the technology disclosed in the present invention. Figure 3 is a SEM diagram showing the electroplated film layer formed by deposition of the pollution-free electroplating solution of the present invention at different magnifications according to the technology disclosed in the present invention. Implementation
[0011] To fully understand the purpose, features and effects of the present invention, the present invention will be described in detail below with reference to the following specific embodiments and accompanying drawings.
[0012] The electroplating solution disclosed in this invention is suitable for electroplating processes. The electroplating solution includes choline chloride, urea and cobalt chloride, wherein the molar concentration ratio of choline chloride to urea is 1:2 and the molar concentration of cobalt chloride is 0.3M.
[0013] Next, please refer to Figure 1. Figure 1 is a flowchart illustrating an embodiment of the method for preparing the electroplating solution according to the technology disclosed in this invention. Step S11: Mix choline chloride and urea, and heat to 80°C to form a colorless and transparent ionic liquid (first mixed solution), wherein the molar concentration ratio of choline chloride to urea is 1:2. It should be noted that the proportion of choline chloride used in this invention is 560 g / L, which is equivalent to a molar concentration of 4M, while the proportion of urea used is 480 g / L, which is equivalent to a molar concentration of 8M. Therefore, the molar concentration ratio of choline chloride to urea is 1:2. Further, in this invention, the range of choline chloride is 460 g / L to 660 g / L, and the range of urea is 380 g / L to 580 g / L. Preferably, the first mixed solution is formed by mixing 560 g / L of choline chloride and 480 g / L of urea.
[0014] Next, in step S12: cobalt chloride is added to the first mixed solution to form an electroplating solution. In this step, the molar concentration of cobalt chloride is 0.3M, and stirring is performed during mixing to ensure that the cobalt chloride and the first mixed solution are uniformly mixed. The purpose of adding cobalt chloride in this invention is to provide a source of metal ions for the film layer deposited on the workpiece 14 to be electroplated (as shown in Figure 2). Therefore, in this invention, cobalt metal is to be plated on the workpiece 14 to be electroplated (as shown in Figure 2), and cobalt chloride is selected because its cobalt ions are of the same material as the target material (cobalt) used in the electroplating equipment 10 (as shown in Figure 2).
[0015] Please refer to Figure 2. Figure 2 is a schematic diagram of the electroplating equipment used in the pollution-free electroplating solution disclosed in this invention. In Figure 2, the electroplating equipment 10 includes an electroplating tank 11, a pollution-free electroplating solution 12 contained in the electroplating tank 11, a target material 13 and a workpiece 14 to be electroplated placed in the electroplating tank 11, and a portion of the target material 13 and the workpiece 14 to be electroplated are immersed in the pollution-free electroplating solution 12. It should be noted that the pollution-free electroplating solution 12 in Figure 2 includes choline chloride, urea and cobalt chloride, and their concentrations and proportions are the same as described above, and will not be repeated here.
[0016] The target material 13 and the workpiece 14 to be electroplated are electrically connected to the positive and negative terminals of the power supply 15, respectively. The target material 13 must be a conductive material; in this embodiment, the target material 13 is cobalt. When the power supply 15 is started, it provides DC power to the target material 13 and the workpiece 14 to be electroplated for the electroplating process. In the electroplating process, the half-reaction of the positive electrode is... The half-reaction at the negative electrode is: Specifically, target 13 releases electrons. And become metal ions Dissolved in electroplating solution 12, while the metal ions to be plated in electroplating solution 12 Accepted electronic , reduction to form metal atoms And deposited on the surface of the workpiece 14 to be electroplated.
[0017] It should be noted that a pretreatment step is performed on the workpiece 14 to be electroplated before the electroplating process. The pretreatment step includes: first, polishing the surface of the workpiece 14 with sandpaper, or rinsing with diluted hydrochloric acid to remove rust spots. Next, the workpiece 14 with the rust removed is cleaned with sodium hydroxide to remove surface oil. Finally, the workpiece 14 is rinsed with distilled water to complete the pretreatment step. After the electroplating process is completed, the workpiece 14 is removed from the electroplating tank 11 and rinsed with distilled water to remove any residual electroplating solution 12. Further, the distilled water is removed with acetone, resulting in a metal workpiece with a deposited coating. It should be noted that the electroplating process of this invention can be performed at room temperature and does not require heating of the electroplating solution 12. In actual operation, a magnet can be placed in the electroplating solution and continuously rotated to uniformly stir the electroplating solution 12. In this operation, the rotational speed of the magnet is related to the internal stress of the electroplating film layer deposited on the surface of the workpiece 14 to be electroplated. Therefore, the faster the magnet rotates, the brighter the electroplating film layer formed on the surface of the workpiece 14 to be electroplated. In this embodiment, the rotational speed of the magnet is preferably between 300 rpm and 1,000 rpm.
[0018] In one embodiment, the operating temperature of the electroplating solution 12 is 60°C, the electroplating time is 2 hours, the current of the power supply 15 is controlled between 0.01A (Amperes) and 0.05A, and the voltage is controlled below 20V (Volts). After the electroplating operation is completed, the electroplated workpiece 14 is removed from the electroplating solution 12 and then subjected to a heat treatment step. In this invention, the heat treatment step involves placing the electroplated workpiece 14 in a vacuum environment with pure oxygen and a temperature of 400°C for heat treatment, and holding the heat treatment at this temperature for 4 hours. After the heat treatment is completed and cooled to room temperature, an oxide coating film, a cobalt oxide film, formed by the electroplating solution disclosed in this invention can be obtained. This oxide coating film is deposited on the surface of the workpiece to be electroplated, and a cobalt oxide coating film is formed on the surface of the electroplated workpiece after the above-mentioned heat treatment.
[0019] Next, please refer to Figure 3. Figure 3 is a SEM image of an electroplated workpiece with a deposited electroplated film layer obtained under an oxygen-filled environment at a temperature of 400°C, showing different magnifications according to the technology disclosed in this invention. Figures 3 and 4 show that the formation of nanoscale, cone-shaped crystalline morphology on the surface has a positive correlation with the mechanical and physical properties of the material, improving surface hardness and wear resistance, and significantly reducing the oxygen-filled heat treatment time after sputtering.
[0020] In summary, the pollution-free electroplating solution obtained by the preparation method of the present invention consists of non-toxic and environmentally friendly components, and does not use any strong acid solutions. When applied to actual mass production electroplating, it will not cause serious pollution to the working environment and the ecological environment.
[0021] 10: Electroplating equipment 11: Electroplating bath 12: Electroplating solution 13: Target Material 14: Workpiece to be electroplated 15: Power Supply S11-S14: Preparation steps of electroplating solution S11-S12: Preparation steps of electroplating solution
Claims
1. An electroplating solution suitable for an electroplating process to form a cobalt oxide coating on a surface of a workpiece to be electroplated, the electroplating solution comprising: Choline monochloride; One urea, the molar concentration ratio of the choline chloride to the urea is 1:2; And cobalt chloride, with a molar concentration of 0.3 M.
2. A method for preparing an electroplating solution suitable for an electroplating process to form a cobalt oxide coating on a surface of a workpiece to be electroplated, the method comprising the following steps: mixing choline chloride and urea to form a first mixed solution, wherein the molar concentration ratio of choline chloride to urea is 1:2; and adding cobalt chloride to the first mixed solution to form the electroplating solution, wherein the molar concentration of the cobalt chloride added to the first mixed solution is 0.3M.
3. A method for forming a cobalt oxide coating on a workpiece to be electroplated using the electroplating solution as described in claim 1 or 2 via an electroplating process, comprising: An electroplating apparatus is provided, comprising: an electroplating tank; an electroplating solution contained within the electroplating tank; a cobalt target immersed in the electroplating solution; and a workpiece to be electroplated, immersed in the electroplating solution; activating a power supply to provide a DC current to the cobalt target and the workpiece to be electroplated to form a cobalt oxide film on a surface of the workpiece to be electroplated; and performing a heat treatment step on the workpiece having the cobalt oxide film in a vacuum environment, such that the cobalt oxide film is formed on the surface of the workpiece to be electroplated.