A cyanide-free silver-nickel alloy stabilizer and its application

Abstract

The present invention relates to the technical field of metal surface treatment, and in particular to a cyanide-free silver-nickel alloy stabilizer; the cyanide-free silver-nickel alloy stabilizer is composed of 2-thiophene ethanol and tranexamic acid; the preparation method is as follows: S1: adding deionized water to 2-thiophene ethanol to prepare a 2-thiophene ethanol solution; S2: preparing tranexamic acid for standby use; S3: preparing a stabilizer: adding the tranexamic acid prepared in step S2 to the 2-thiophene ethanol solution prepared in step 1, and stirring fully; then settling to a predetermined amount with deionized water, stirring continuously until uniform mixing, and obtaining a cyanide-free silver-nickel alloy stabilizer. It also relates to the application of adding the above-mentioned cyanide-free silver-nickel alloy stabilizer to a cyanide-free silver-nickel alloy plating solution. The problem of unstable corrosion resistance of silver-nickel alloy is solved.

Description

Technical Field

[0001] The invention relates to the technical field of metal surface treatment, in particular to a cyanide-free silver-nickel alloy stabilizer and application thereof. Background Art

[0002] Conductive rings are widely used in military products as the core parts of complex equipment and instruments. Conductive rings are required to rotate 100 million times in five years for military products, and 50 million times in five years for civilian products. Ag-Ni alloy has high conductivity, mechanical properties and chemical properties, which can meet the application of conductive ring coating in military and civilian products. So far, the most mature Ag alloy electroplating process is still the century-old cyanide electroplating. However, cyanide is a highly toxic chemical, which has the potential to seriously harm the environment and workers.

[0003] In the electroplating industry, cyanide is controversial due to its highly toxic properties and huge threats to the environment and human health. Although the cyanide electroplating process is stable, easy to maintain, and has excellent coating performance, the wastewater treatment problems generated during its use and the health risks to operators have always been issues that the industry needs to solve urgently. With the increasingly stringent environmental regulations and the improvement of public environmental awareness, the traditional cyanide electroplating process is facing the pressure of being eliminated. Against this background, cyanide-free electroplating technology came into being and became an important development direction for the electroplating industry. Cyanide-free electroplating technology can not only reduce environmental pollution, but also reduce the health risks to operators, while maintaining or improving the performance of the coating.

[0004] The development of cyanide-free silver-nickel alloy plating technology provides a new solution for the production of electrical contact materials such as conductive rings. Compared with traditional cyanide electroplating, cyanide-free silver-nickel alloy plating technology has obvious advantages in environmental safety, operational safety and wastewater treatment costs. The cyanide-free electroplating solution has good deep plating ability, bonding strength, conductivity and other properties, which can meet the high performance requirements of products such as conductive rings.

[0005] However, the stability of the nickel content in the coating is poorer than that of the cyanide system, resulting in unstable corrosion resistance of the silver-nickel alloy. Summary of the invention

[0006] The invention provides a cyanide-free silver-nickel alloy stabilizer and application thereof, which can solve the problem of unstable corrosion resistance of the silver-nickel alloy.

[0007] In order to solve the above technical problems, the present application provides the following technical solutions: 1. A cyanide-free silver-nickel alloy stabilizer, characterized in that the cyanide-free silver-nickel alloy stabilizer is composed of 2-thiopheneethanol and tranexamic acid; The preparation method is as follows: S1: adding deionized water to 2-thiopheneethanol to prepare a 2-thiopheneethanol solution; S2: prepare tranexamic acid for use; S3: preparing a stabilizer: adding the tranexamic acid prepared in step S2 to the 2-thiophene ethanol solution prepared in step 1, and stirring thoroughly; then diluting to a predetermined amount with deionized water, and continuously stirring until the mixture is uniformly mixed, to obtain a cyanide-free silver-nickel alloy stabilizer.

[0008] Further: the mass ratio of the 2-thiopheneethanol to tranexamic acid is 1:(2-6).

[0009] Further: the concentration of the 2-thiopheneethanol in the cyanide-free silver-nickel alloy plating solution is 0.5-1 g / L.

[0010] Further: the concentration of tranexamic acid in the cyanide-free silver-nickel alloy plating solution is 2 to 3 g / L.

[0011] A cyanide-free silver-nickel alloy stabilizer is used, wherein the cyanide-free silver-nickel alloy stabilizer according to any one of claims 1 to 4 is used in a cyanide-free silver-nickel alloy plating solution.

[0012] Further: the cyanide-free silver-nickel alloy plating solution comprises the following components by mass concentration: 70-90 g / L nickel sulfate hexahydrate, 5-7 g / L silver methanesulfonate, 200-300 g / L potassium iodide, 25-35 g / L succinic acid, and 25-35 g / L glycine.

[0013] Further: 6. The cyanide-free silver-nickel alloy plating solution comprises the following components by mass concentration: 80 g / L nickel sulfate hexahydrate, 6 g / L silver methanesulfonate, 250 g / L potassium iodide, 30 g / L succinic acid, and 30 g / L glycine.

[0014] Further: when electroplating is performed using a cyanide-free silver-nickel alloy plating solution to which a cyanide-free silver-nickel alloy stabilizer is added: the electroplating temperature is controlled at 25 to 35°C, the electroplating time is 1 to 1.5 hours, the electroplating cathode current density is 0.5 to 1.5 A / dm², and a nickel plate is used as an anode.

[0015] The basic principle of this scheme is that the cyanide-free silver-nickel alloy stabilizer of this scheme is composed of two main components, namely 2-thiopheneethanol and tranexamic acid. The combination of these two compounds can effectively improve the stability of the nickel content in the silver-nickel alloy coating. The stabilizer of this scheme is added to the cyanide-free silver-nickel alloy electroplating solution, which can further stabilize the nickel content in the coating at 10% to 15% without changing the original coating performance and the stability of the plating solution, so that the corrosion resistance of the coating is stable and reaches the level of cyanide electroplating coating, which can completely replace the cyanide silver-nickel alloy plating process and play the purpose of protecting the environment. The stabilizer of the present invention has the characteristics of environmental protection, non-toxicity, low dosage concentration, low use cost, etc., and is suitable for industrial production of electroplating.

[0016] Beneficial effects of this solution: Environmentally friendly and non-toxic: The stabilizer of the present invention is cyanide-free, which means that it does not contain highly toxic cyanide and is therefore safer for the environment and workers.

[0017] Improve corrosion resistance: By controlling the nickel content at 10% to 15%, the present invention can make the corrosion resistance of the silver-nickel alloy coating reach a level equivalent to that of traditional cyanide electroplating.

[0018] Stable performance: The electroplating solution with the addition of stabilizer can further stabilize the nickel content in the coating without changing the original coating performance and the stability of the plating solution.

[0019] Cost-effectiveness: Due to the low concentration of stabilizer, the cost of use is low and it is suitable for industrial production.

[0020] Replacement of traditional process: The stabilizer of the present invention can completely replace the traditional cyanide silver-nickel alloy plating process, which helps to reduce environmental pollution.

[0021] Meeting production needs: Under the same electroplating time and conditions, the stabilizer of the present invention has a significant effect on stabilizing the nickel content of the coating, and can meet the needs of modern production applications.

[0022] Wide application scope: The stabilizer of the present invention is suitable for production requirements in different fields and has good market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the steps for preparing a cyanide-free silver-nickel alloy stabilizer. DETAILED DESCRIPTION

[0024] The following is further described in detail through specific implementation methods: Embodiment 1 is as attached Figure 1 As shown, The present invention is further described in detail with reference to the following examples. The following examples are merely illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0025] When a certain amount, concentration or other value or parameter is expressed in the form of a range, a preferred range, or a preferred upper and lower numerical limit, it should be understood that it is equivalent to specifically revealing any range by combining any pair of upper range limits or preferred numerical values ​​with any lower range limit or preferred numerical value, regardless of whether the range is specifically disclosed. Unless otherwise indicated, the numerical range values ​​listed herein include the endpoints of the range, and all integers and fractions within the range.

[0026] Unless otherwise indicated, all percentages, parts, ratios, etc. herein are by weight.

[0027] The materials, methods, and examples herein are illustrative and are not to be construed as limiting unless specifically stated.

[0028] In the following examples, in order to test the effect of using the stabilizer in a cyanide-free silver-nickel alloy plating solution, the appearance, thickness, silver and nickel content of the coating were tested.

[0029] Example 1 1. The mass concentration ratio of each component of the stabilizer described in this embodiment is as follows: 2-Thiopheneethanol 0.7g / L Tranexamic acid 2.5 g / L 2. The preparation method of the stabilizer described in this embodiment is as follows: S1: Prepare 2-thiophene ethanol solution: weigh 0.7 g of 2-thiophene ethanol and add it into 500 ml of deionized water, stir until a uniform solution is obtained, and set aside; S2: Weigh tranexamic acid: Use an analytical balance to weigh 2.5 g of tranexamic acid and set aside; S3: Prepare a stabilizer: Add the tranexamic acid weighed in step (S2) to the 2-thiophene ethanol solution prepared in step (S1), stir well to mix them completely, and then dilute to 1 L with deionized water, and continue stirring to mix them evenly.

[0030] 3. Performance testing 10 ml of the stabilizer prepared in Example 1 is added to 1 L of cyanide-free silver-nickel alloy electroplating, and the workpiece is placed in the prepared electroplating solution for electroplating. After electroplating, the plated workpiece is taken out, the thickness, silver and nickel content of the coating are measured, and the appearance of the coating is observed. The workpiece is generally a copper piece.

[0031] The cyanide-free silver-plated nickel alloy electroplating solution used in this embodiment is: Nickel sulfate hexahydrate 80g / L Silver methanesulfonate 6g / L Potassium iodide 250g / L Succinic acid 30g / L Glycine 30 g / L The electroplating process conditions in this embodiment are: Plating temperature 30℃ Electroplating time 1h Electroplating cathode current density 1A / dm 2 Anode nickel plate used for electroplating The workpieces were electroplated under the same conditions using the same cyanide-free silver-nickel alloy plating solution without the above stabilizer, and the thickness, silver and nickel content of the silver-nickel coating were determined using a Fischei tester, and the appearance of the coating was observed.

[0032] 4. Test results The thickness of the electroplated workpiece after adding the stabilizer is 11.53μm, the silver content is 87.3%, the nickel content is 12.7%, the coating appearance is delicate and bright, and the coating is shiny. The thicker the coating thickness, the better the corrosion resistance of the coating. The corrosion resistance of the coating varies with the nickel content in the silver-nickel alloy. When the nickel content is lower than 9%, the corrosion resistance is poor. When it is higher than 15%, it is easy to passivate and cause film defects and reduced corrosion resistance. Therefore, the nickel content in the coating must be strictly controlled. The sample of the present invention is to prepare a silver-nickel coating, and its nickel content should be preferably between 10% and 15%. The coating thickness of the electroplated workpiece without adding the above stabilizer is 11.73μm, the nickel content is 8.72%, the coating appearance is delicate and bright, and the coating is shiny.

[0033] Example 2 1. The mass concentration ratio of each component of the stabilizer described in this embodiment is as follows: 2-Thiopheneethanol 0.65g / L Tranexamic acid 2.9 g / L 2. The preparation method of the stabilizer described in this embodiment is as follows: S1: Prepare 2-thiophene ethanol solution: weigh 0.65 g of 2-thiophene ethanol and add it into 500 ml of deionized water, stir until a uniform solution is obtained, and set aside; S2: Weigh tranexamic acid: Use an analytical balance to weigh 2.9 g of tranexamic acid and set aside; S3: Prepare a stabilizer: Add the tranexamic acid weighed in step (S2) to the 2-thiophene ethanol solution prepared in step (S1), stir well to mix them completely, and then dilute to 1 L with deionized water, and continue stirring to mix them evenly.

[0034] 3. Performance testing 10 ml of the stabilizer prepared in Example 2 is added to every 1 L of cyanide-free silver-nickel alloy electroplating, and the workpiece is placed in the prepared electroplating solution for electroplating. After electroplating, the plated workpiece is taken out, the thickness, silver and nickel content of the coating are measured, and the appearance of the coating is observed. The workpiece is generally a copper piece.

[0035] The cyanide-free silver-plated nickel alloy electroplating solution used in this embodiment is: Nickel sulfate hexahydrate 80g / L Silver methanesulfonate 6g / L Potassium iodide 250g / L Succinic acid 30g / L Glycine 30 g / L The electroplating process conditions in this embodiment are: Plating temperature 30℃ Electroplating time 1h Electroplating cathode current density 1A / dm 2 Anode nickel plate used for electroplating The workpieces were electroplated under the same conditions using the same cyanide-free silver-nickel alloy plating solution without the above stabilizer, and the thickness, silver and nickel content of the silver-nickel coating were determined using a Fischei tester, and the appearance of the coating was observed.

[0036] 4. Test results After adding stabilizer, the coating thickness of the electroplated workpiece is 11.29μm, the silver content is 86.73%, the nickel content is 13.27%, the coating appearance is delicate and bright, and the coating is shiny.

[0037] Without adding the above stabilizer, the coating thickness of the electroplated workpiece is 11.43μm, the nickel content is 15.28%, the coating appearance is delicate and bright, and the coating is shiny.

[0038] Example 3 1. The mass concentration ratio of each component of the stabilizer described in this embodiment is as follows: 2-Thiopheneethanol 0.8g / L Tranexamic acid 2.25 g / L 2. The preparation method of the stabilizer described in this embodiment is as follows: S1: Prepare 2-thiophene ethanol solution: weigh 0.8 g of 2-thiophene ethanol and add it into 500 ml of deionized water, stir until a uniform solution is obtained, and set aside; S2: Weigh tranexamic acid: Use an analytical balance to weigh 2.25 g of tranexamic acid and set aside; S3: Prepare a stabilizer: Add the tranexamic acid weighed in step (S2) to the 2-thiophene ethanol solution prepared in step (S1), stir well to mix them completely, and then dilute to 1 L with deionized water, and continue stirring to mix them evenly.

[0039] 3. Performance testing 10 ml of the stabilizer prepared in Example 3 is added to 1 L of cyanide-free silver-nickel alloy electroplating, and the workpiece is placed in the prepared electroplating solution for electroplating. After electroplating, the plated workpiece is taken out, the thickness, silver and nickel content of the coating are measured, and the appearance of the coating is observed. The workpiece is generally a copper piece.

[0040] The cyanide-free silver-plated nickel alloy electroplating solution used in this embodiment is: Nickel sulfate hexahydrate 80g / L Silver methanesulfonate 6g / L Potassium iodide 250g / L Succinic acid 30g / L Glycine 30 g / L The electroplating process conditions in this embodiment are: Plating temperature 30℃ Electroplating time 1h Electroplating cathode current density 1A / dm 2 Anode nickel plate used for electroplating The workpieces were electroplated under the same conditions using the same cyanide-free silver-nickel alloy plating solution without the above stabilizer, and the thickness, silver and nickel content of the silver-nickel coating were determined using a Fischei tester, and the appearance of the coating was observed.

[0041] 4. Test results After adding stabilizer, the coating thickness of the electroplated workpiece is 12.14μm, the silver content is 89.37%, the nickel content is 10.63%, the coating appearance is delicate and bright, and the coating is shiny.

[0042] Without adding the above stabilizer, the coating thickness of the electroplated workpiece is 11.84μm, the nickel content is 14.72%, the coating appearance is delicate and bright, and the coating is shiny.

[0043] Example 4 1. The mass concentration ratio of each component of the stabilizer described in this embodiment is as follows: 2-Thiopheneethanol 0.5g / L Tranexamic acid 2g / L 2. The preparation method of the stabilizer described in this embodiment is as follows: S1: Prepare 2-thiophene ethanol solution: weigh 0.5 g of 2-thiophene ethanol and add it into 500 ml of deionized water, stir until a uniform solution is obtained, and set aside; S2: Weigh tranexamic acid: Use an analytical balance to weigh 2 g of tranexamic acid and set aside; S3: Prepare a stabilizer: Add the tranexamic acid weighed in step (S2) to the 2-thiophene ethanol solution prepared in step (S1), stir well to mix them completely, and then dilute to 1 L with deionized water, and continue stirring to mix them evenly.

[0044] 3. Performance testing 10 ml of the stabilizer prepared in Example 4 is added to 1 L of cyanide-free silver-nickel alloy electroplating, and the workpiece is placed in the prepared electroplating solution for electroplating. After electroplating, the plated workpiece is taken out, the thickness, silver and nickel content of the coating are measured, and the appearance of the coating is observed. The workpiece is generally a copper piece.

[0045] The cyanide-free silver-plated nickel alloy electroplating solution used in this embodiment is: Nickel sulfate hexahydrate 80g / L Silver methanesulfonate 6g / L Potassium iodide 250g / L Succinic acid 30g / L Glycine 30 g / L The electroplating process conditions in this embodiment are: Plating temperature 30℃ Electroplating time 1h Electroplating cathode current density 1A / dm 2 Anode nickel plate used for electroplating The workpieces were electroplated under the same conditions using the same cyanide-free silver-nickel alloy plating solution without the above stabilizer, and the thickness, silver and nickel content of the silver-nickel coating were determined using a Fischei tester, and the appearance of the coating was observed.

[0046] 4. Test results After adding stabilizer, the coating thickness of the electroplated workpiece is 11.97μm, the silver content is 87.82%, the nickel content is 12.18%, the coating appearance is delicate and bright, and the coating is shiny.

[0047] The coating thickness of the electroplated workpiece without adding the above stabilizer is 10.83μm, the nickel content is 17.92%, the coating appearance is delicate and bright, and the coating is shiny.

[0048] Example 5 1. The mass concentration ratio of each component of the stabilizer described in this embodiment is as follows: 2-Thiopheneethanol 1g / L Tranexamic acid 3g / L 2. The preparation method of the stabilizer described in this embodiment is as follows: S1: Prepare 2-thiophene ethanol solution: weigh 1 g of 2-thiophene ethanol and add it into 500 ml of deionized water, stir until a uniform solution is obtained, and set aside; S2: Weigh tranexamic acid: Use an analytical balance to weigh 3 g of tranexamic acid and set aside; S3: Prepare a stabilizer: Add the tranexamic acid weighed in step (S2) to the 2-thiophene ethanol solution prepared in step (S1), stir well to mix them completely, and then dilute to 1 L with deionized water, and continue stirring to mix them evenly.

[0049] 3. Performance testing 10 ml of the stabilizer prepared in Example 5 is added to 1 L of cyanide-free silver-nickel alloy electroplating, and the workpiece is placed in the prepared electroplating solution for electroplating. After electroplating, the plated workpiece is taken out, the thickness, silver and nickel content of the coating are measured, and the appearance of the coating is observed. The workpiece is generally a copper piece.

[0050] The cyanide-free silver-plated nickel alloy electroplating solution used in this embodiment is: Nickel sulfate hexahydrate 80g / L Silver methanesulfonate 6g / L Potassium iodide 250g / L Succinic acid 30g / L Glycine 30 g / L The electroplating process conditions in this embodiment are: Plating temperature 30℃ Electroplating time 1h Electroplating cathode current density 1A / dm 2 Anode nickel plate used for electroplating The workpieces were electroplated under the same conditions using the same cyanide-free silver-nickel alloy plating solution without the above stabilizer, and the thickness, silver and nickel content of the silver-nickel coating were determined using a Fischei tester, and the appearance of the coating was observed.

[0051] 4. Test results After adding stabilizer, the coating thickness of the electroplated workpiece is 11.27μm, the silver content is 86.21%, the nickel content is 13.79%, the coating appearance is delicate and bright, and the coating is shiny.

[0052] The coating thickness of the electroplated workpiece without adding the above stabilizer is 11.17μm, the nickel content is 7.71%, the coating appearance is delicate and bright, and the coating is shiny.

[0053] The above examples further show that the present invention has no adverse effect on the original properties of the plating solution and the plating layer, and can significantly stabilize the nickel content of the plating layer at 10% to 15%, thereby stabilizing the corrosion resistance of the plating layer. Under the same electroplating time and conditions, it has a significant effect on stabilizing the nickel content of the plating layer, and can fully meet the needs of current production applications.

[0054] According to the examples provided in the document, we can compare the coating properties of electroplated workpieces with and without stabilizers to draw experimental conclusions. The following are the comparison results of various examples: Summary of experimental results: Embodiment 1: Add stabilizer: coating thickness 11.53μm, silver content 87.3%, nickel content 12.7%, delicate and bright appearance.

[0055] Without stabilizer: coating thickness 11.73μm, nickel content 8.72%, delicate and bright appearance.

[0056] Embodiment 2: Add stabilizer: coating thickness 11.29μm, silver content 86.73%, nickel content 13.27%, delicate and bright appearance.

[0057] Without stabilizer: coating thickness 11.43μm, nickel content 15.28%, delicate and bright appearance.

[0058] Embodiment 3: Add stabilizer: coating thickness 12.14μm, silver content 89.37%, nickel content 10.63%, delicate and bright appearance.

[0059] Without stabilizer: coating thickness 11.84μm, nickel content 14.72%, delicate and bright appearance.

[0060] Embodiment 4: Add stabilizer: coating thickness 11.97μm, silver content 87.82%, nickel content 12.18%, delicate and bright appearance.

[0061] Without stabilizer: coating thickness 10.83μm, nickel content 17.92%, delicate and bright appearance.

[0062] Embodiment 5: Add stabilizer: coating thickness 11.27μm, silver content 86.21%, nickel content 13.79%, delicate and bright appearance.

[0063] Without stabilizer: coating thickness 11.17μm, nickel content 7.71%, delicate and bright appearance.

[0064] From the above results, we can get: 1. Nickel content control: In all examples, after adding the stabilizer, the nickel content was effectively controlled within the range of 10% to 15%, while the nickel content of the samples without the stabilizer exceeded this ideal range, indicating that the stabilizer has a significant effect on controlling the nickel content.

[0065] 2. Coating thickness and appearance: The coating thickness with stabilizer added is not much different from that without stabilizer added, indicating that stabilizer has little effect on coating thickness. The appearance of all samples is delicate and bright, indicating that the addition of stabilizer has no negative impact on the appearance of the coating.

[0066] 3. Silver content: The silver content of samples with stabilizer added was slightly different, but all remained at a high level, which shows that the stabilizer helps to maintain a high silver content in the silver-nickel alloy.

[0067] 4. Corrosion resistance: Since the nickel content is controlled between 10% and 15%, it can be inferred that the coating with the addition of stabilizer has better corrosion resistance, because when the nickel content is lower than 9%, the corrosion resistance is poor, and when it is higher than 15%, passivation is prone to difficulty.

[0068] 5. Stability: The use of stabilizers significantly improves the stability of the nickel content in the coating, which is crucial to improving the quality and consistency of silver-nickel alloy electroplating.

[0069] In summary, the experimental results show that the use of the stabilizer of the present invention can effectively control the nickel content in the silver-nickel alloy electroplating layer, improve the corrosion resistance and stability of the coating, while maintaining the thickness and appearance quality of the coating, meeting the needs of industrial production.

[0070] The above are only embodiments of the present invention. The invention is not limited to the fields involved in this implementation case. The common sense such as the known specific structures and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field to which the invention belongs before the application date or the priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to explain the content of the claims.

Claims

1. A cyanide-free silver-nickel alloy stabilizer, characterized in that: The cyanide-free silver-nickel alloy stabilizer consists of 2-thiopheneethanol and tranexamic acid; The preparation method is as follows: S1: adding deionized water to 2-thiopheneethanol to prepare a 2-thiopheneethanol solution; S2: prepare tranexamic acid for use; S3: preparing a stabilizer: adding the tranexamic acid prepared in step S2 to the 2-thiophene ethanol solution prepared in step 1, and stirring thoroughly; then diluting to a predetermined amount with deionized water, and continuously stirring until the mixture is uniformly mixed, to obtain a cyanide-free silver-nickel alloy stabilizer.

2. A cyanide-free silver-nickel alloy stabilizer according to claim 1, characterized in that: The mass ratio of the 2-thiopheneethanol to tranexamic acid is 1:(2-6).

3. A cyanide-free silver-nickel alloy stabilizer according to claim 1, characterized in that: The concentration of the 2-thiopheneethanol in the cyanide-free silver-nickel alloy plating solution is 0.5-1 g / L.

4. A cyanide-free silver-nickel alloy stabilizer according to claim 1, characterized in that: The concentration of tranexamic acid in the cyanide-free silver-nickel alloy plating solution is 2-3 g / L.

5. An application of a cyanide-free silver-nickel alloy stabilizer, characterized in that: The cyanide-free silver-nickel alloy stabilizer according to any one of claims 1 to 4 is used in a cyanide-free silver-nickel alloy plating solution.

6. The use of a cyanide-free silver-nickel alloy stabilizer according to claim 5, characterized in that: The cyanide-free silver-nickel alloy plating solution comprises the following components in terms of mass concentration: 70-90 g / L nickel sulfate hexahydrate, 5-7 g / L silver methanesulfonate, 200-300 g / L potassium iodide, 25-35 g / L succinic acid, and 25-35 g / L glycine.

7. The use of a cyanide-free silver-nickel alloy stabilizer according to claim 6, characterized in that: The cyanide-free silver-nickel alloy plating solution comprises the following components by mass concentration: 80 g / L nickel sulfate hexahydrate, 6 g / L silver methanesulfonate, 250 g / L potassium iodide, 30 g / L succinic acid, and 30 g / L glycine.

8. The use of a cyanide-free silver-nickel alloy stabilizer according to claim 7, characterized in that: When electroplating is performed using a cyanide-free silver-nickel alloy plating solution to which a cyanide-free silver-nickel alloy stabilizer is added: the electroplating temperature is controlled at 25-35°C, the electroplating time is 1-1.5 hours, the electroplating cathode current density is 0.5-1.5A / dm², and a nickel plate is used as the anode.

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