Stabilizer for nickel content in cyanide-free alkaline zinc-nickel alloy coating and application thereof
By adding 4-hydroxypyridine, urethane and quinolamide alcohol stabilizers to the cyanobacterial alkaline zinc-nickel alloy plating solution, the problem of difficult control of nickel content is solved, the stability and uniformity of nickel content in the plating layer is achieved, and the corrosion resistance and appearance quality of the plating layer are improved.
Patent Information
- Application Number
- CN202510466968.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-15
- Publication Date
- 2025-07-04
AI Technical Summary
The nickel content in the existing cyanobacterial zinc-nickel alloy coating is difficult to stabilize between 12 and 14%, resulting in the non-bright passivation color of the hexavalent chromium coating and the corrosion resistance is reduced.
4-hydroxypyridine, ethyl carbamate and quinamidamide alcohol were used as stabilizers and added to the cyanobacterial alkaline zinc-nickel alloy electroplating solution to adjust the nickel content in the plating layer between 12 and 14%, and improve the uniformity and stability of the plating layer.
Without changing the performance of the original electroplating solution, the nickel content in the plating layer is stabilized to ensure that the plating layer has excellent performance and appearance, and is suitable for large-scale industrial production.
Abstract
Description
Technical Field
[0001] The present invention relates to a stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating and its application, belonging to the technical field of metal surface treatment. Background Art
[0002] The zinc-nickel alloy coating is a new type of excellent protective coating, suitable for use in harsh industrial atmospheres and severe marine environments. Its corrosion resistance is significantly better than that of pure zinc coatings, mainly due to the addition of nickel. The corrosion resistance of a zinc-nickel alloy coating with a nickel content of 7-9% is more than 3 times that of a zinc coating, and the corrosion resistance of a zinc-nickel alloy coating with a nickel content of about 13% is more than 5 times that of a zinc coating, showing the best corrosion resistance. At present, the main problem in the market zinc-nickel alloy process is that it is difficult to control the nickel content in the coating at about 13%, and its content is often higher than 14%, even in the range of 18-20%. After the nickel content in the coating is higher than 14%, the color of the hexavalent chromium color passivation of the coating is not bright, and the corrosion resistance is significantly reduced. Therefore, it has great value to study a stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating and apply it to the existing cyanide-free alkaline zinc-nickel alloy electroplating process to obtain a coating with a nickel content stable between 12-14%, obtaining the best passivation appearance and excellent corrosion resistance to meet the needs of actual production. Summary of the Invention
[0003] The purpose of the present invention is to provide a stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating and its application, which solves the problem of excessive nickel content in the coating of traditional cyanide-free alkaline zinc-nickel alloys.
[0004] The technical solution of the present invention: A stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating, calculated by mass concentration, the concentrations of each component in the stabilizer are: 4-hydroxypyridine 30-50 g / L, ethyl carbamate 30-50 g / L, and quinamide alcohol 3-5 g / L.
[0005] In the aforementioned stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating, calculated by mass ratio, the ratio of 4-hydroxypyridine, ethyl carbamate, and quinamide alcohol is 10:10:1.
[0006] An application of a stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating in the preparation of a cyanide-free alkaline zinc-nickel alloy coating.
[0007] In the application of the aforementioned stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating in the preparation of a cyanide-free alkaline zinc-nickel alloy coating, the stabilizer is added to the electroplating solution as a component of the cyanide-free alkaline zinc-nickel alloy electroplating solution. The concentrations of each component of the stabilizer in the electroplating solution are: 4-hydroxypyridine 0.3-0.5 g / L, ethyl carbamate 0.3-0.5 g / L, and quinamide alcohol 0.03-0.05 g / L.
[0008] In the application of the stabilizer for nickel content in the above-mentioned cyanide-free alkaline zinc-nickel alloy coating in the preparation of the cyanide-free alkaline zinc-nickel alloy coating, the electroplating solution contains the following components by mass concentration: 4-hydroxypyridine 0.3 - 0.5 g / L, ethyl carbamate 0.3 - 0.5 g / L, quinamide alcohol 0.03 - 0.05 g / L, zinc oxide 8 - 10 g / L, sodium hydroxide 110 - 140 g / L, nickel sulfate 4 - 5 g / L, triethanolamine 20 - 25 g / L, tetraethylenepentamine 5 - 8 g / L, tetrahydroxypropyl ethylenediamine 20 - 30 g / L, DPE-3 4 - 6 ml / L.
[0009] In the application of the stabilizer for nickel content in the above-mentioned cyanide-free alkaline zinc-nickel alloy coating in the preparation of the cyanide-free alkaline zinc-nickel alloy coating, the electroplating temperature range is 20 - 25 °C, the electroplating time range is 50 - 70 min, and the electroplating cathode current density range is 1.0 - 2.0 A / dm 2 , and the anode used for electroplating is an iron plate plated with semi-bright nickel or a nickel plate.
[0010] In the application of the stabilizer for nickel content in the above-mentioned cyanide-free alkaline zinc-nickel alloy coating in the preparation of the cyanide-free alkaline zinc-nickel alloy coating, the stirring method during electroplating is cathode movement, and the movement speed is 3 - 10 m / min.
[0011] Beneficial effects of the present invention: Compared with the prior art, the stabilizer for nickel content in the cyanide-free alkaline zinc-nickel alloy coating of the present invention is added to the cyanide-free alkaline zinc-nickel alloy electroplating solution, which can stabilize the nickel content in the coating between 12% and 14% without changing the properties of the original electroplating solution and the coating, improve the stability of the nickel content in the coating, and ensure that the coating has excellent properties. Quinamide alcohol in the stabilizer can stably maintain the nickel content in the coating, ethyl carbamate can effectively improve the solubility of quinamide alcohol, and 4-hydroxypyridine can greatly improve the uniformity of the alloy content in the cyanide-free zinc-nickel coating. The stabilizer of the present invention has the advantages of simple composition, low dosage concentration, and low cost, and is suitable for large-scale industrial production. Specific embodiments
[0012] The following examples are used to further illustrate the present invention, but they are not used as the basis for limiting the present invention. Examples
[0013] 1. A stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating is composed of the following components: 4-hydroxypyridine 30 g / L Ethyl carbamate 30 g / L Quinamide alcohol 3 g / L.
[0014] 2. The preparation method of the stabilizer described in this example is as follows: 1) Preparation of quinocetol solution: Weigh 3 g of quinocetol and add it to 500 ml of hot deionized water. Stir until a homogeneous solution is obtained, and let it cool for later use. 2) Weigh 4-hydroxypyridine: Weigh 30 g of 4-hydroxypyridine using an analytical balance and set it aside for later use. 3) Weigh ethyl carbamate: Weigh 30 g of ethyl carbamate using an analytical balance and set it aside for later use. 4) Preparation of stabilizer: Add the 4-hydroxypyridine weighed in step (2) to the quinocetol solution prepared in step (1), stir well to make them fully mixed, then slowly add the ethyl carbamate weighed in step (3), and then make up the volume to 1 L with deionized water. Keep stirring until they are evenly mixed.
[0015] 3. Performance testing Add 10 ml of the stabilizer prepared in Example 1 to every 1 L of the cyanide-free alkaline zinc-nickel alloy electroplating solution. Put the workpiece into the prepared electroplating solution for electroplating. After electroplating, take out the electroplated workpiece, measure the thickness and nickel content of the coating, and observe the appearance state of the coating. The workpiece is generally an iron piece.
[0016] The cyanide-free alkaline zinc-nickel alloy electroplating solution used in this example is as follows: Zinc oxide 8 - 10 g / L Sodium hydroxide 110 - 140 g / L Nickel sulfate 4 - 5 g / L Triethanolamine 20 - 25 g / L Tetraethylenepentamine 5 - 8 g / L Tetrahydroxypropyl ethylenediamine 20 - 30 g / L DPE-3 4 - 6 ml / L The electroplating process conditions in this example are as follows: Electroplating temperature 20 °C Electroplating time 60 min Electroplating cathode current density 1 A / dm 2 The anode used for electroplating Iron plate plated with semi-bright nickel Stirring method during electroplating Cathode movement (5 m / min).
[0017] Use the same cyanide-free alkaline zinc-nickel alloy electroplating solution without adding the above stabilizer to electroplate the workpiece under the same conditions. Use Fischer to measure the thickness and nickel content of the zinc-nickel coating and observe the appearance state of the coating.
[0018] 4. Test results After adding the stabilizer, the coating thickness of the electroplated workpiece is 9.33 μm, and the nickel content is 12.55%.
[0019] The coating thickness of the electroplated workpiece without the above stabilizer is 8.15 μm, and the nickel content is 18.98%. Example
[0020] 1. The concentration ratios of the components of the stabilizer described in this example are as follows: 4-Hydroxypyridine 40 g / L Ethyl carbamate 40 g / L Quinamide alcohol 4 g / L.
[0021] 2. The preparation method of the stabilizer described in this example is the same as that of Example 1, except that the amounts of the components are calculated according to the above ratios.
[0022] 3. Performance testing Add 10 ml of the stabilizer prepared in Example 2 to every 1 L of the cyanide-free alkaline zinc-nickel alloy electroplating solution, put the workpiece into the prepared electroplating solution for electroplating. The electroplating conditions in this example are the same as those in Example 1. After electroplating, take out the electroplated workpiece, measure the coating thickness and nickel content, and observe the appearance state of the coating. The workpiece is generally an iron part.
[0023] Similarly, use the cyanide-free alkaline zinc-nickel alloy electroplating solution without the above stabilizer to electroplate the workpiece under the same conditions and conduct testing.
[0024] 4. Test results After adding the stabilizer, the coating thickness of the electroplated workpiece is 9.38 μm, and the nickel content is 12.78%.
[0025] The coating thickness of the electroplated workpiece without the above stabilizer is 9.05 μm, and the nickel content is 19.31%. Example
[0026] 1. The concentration ratios of the components of the stabilizer described in this example are as follows: 4-Hydroxypyridine 50 g / L Ethyl carbamate 50 g / L Quinamide alcohol 5 g / L.
[0027] 2. The preparation method of the stabilizer described in this example is the same as that of Example 1, except that the amounts of the components are calculated according to the above ratios.
[0028] 3. Performance testing Add 10 ml of the stabilizer prepared in Example 3 to every 1 L of the cyanide-free alkaline zinc-nickel alloy electroplating solution, put the workpiece into the prepared electroplating solution for electroplating. The electroplating conditions in this example are the same as those in Example 1. After electroplating, take out the electroplated workpiece, measure the coating thickness and nickel content, and observe the appearance state of the coating. The workpiece is generally an iron part.
[0029] Similarly, a cyanide-free alkaline zinc-nickel alloy electroplating solution without the above stabilizer was used, and electroplated workpieces were compared in parallel under the same conditions and tested.
[0030] 4. Test Results After adding the stabilizer, the coating thickness of the electroplated workpiece is 9.31 μm, and the nickel content is 12.85%.
[0031] After not adding the above stabilizer, the coating thickness of the electroplated workpiece is 9.19 μm, and the nickel content is 17.81%. Example
[0032] 1. The concentration ratios of the components of the stabilizer described in this example are as follows: 4-Hydroxypyridine 35 g / L Ethyl carbamate 35 g / L Quinamidol 3.5 g / L.
[0033] 2. The preparation method of the stabilizer described in this example is the same as that of Example 1, except that the amounts of each component are calculated according to the above ratios.
[0034] Add 10 ml of the stabilizer prepared in Example 4 to every 1 L of the cyanide-free alkaline zinc-nickel alloy electroplating solution, put the workpiece into the prepared electroplating solution for electroplating. The electroplating conditions in this example are the same as those in Example 1. After electroplating, take out the electroplated workpiece, measure the coating thickness and nickel content, and observe the appearance state of the coating. The workpiece is generally an iron part.
[0035] Similarly, a cyanide-free alkaline zinc-nickel alloy electroplating solution without the above stabilizer was used, and electroplated workpieces were electroplated under the same conditions and tested.
[0036] 4. Test Results After adding the stabilizer, the coating thickness of the electroplated workpiece is 9.27 μm, and the nickel content is 12.66%.
[0037] After not adding the above stabilizer, the coating thickness of the electroplated workpiece is 8.76 μm, and the nickel content is 17.64%. Example
[0038] 1. The concentration ratios of the components of the stabilizer described in this example are as follows: 4-Hydroxypyridine 45 g / L Ethyl carbamate 45 g / L Quinamidol 4.5 g / L 2. The preparation method of the stabilizer described in this example is the same as that of Example 1, except that the amounts of each component are calculated according to the above ratios.
[0039] Add 10 ml of the stabilizer prepared in Example 5 to every 1 L of the cyanide-free alkaline zinc-nickel alloy electroplating solution. Place the workpiece into the prepared electroplating solution for electroplating. The electroplating conditions in this example are the same as those in Example 1. After electroplating, take out the electroplated workpiece, measure the thickness and nickel content of the coating, and observe the appearance state of the coating. The workpiece is generally an iron piece.
[0040] Similarly, use a cyanide-free alkaline zinc-nickel alloy electroplating solution without adding the above stabilizer to electroplate the workpiece under the same conditions and conduct detection.
[0041] 4. Detection Results After adding the stabilizer, the coating thickness of the electroplated workpiece is 9.67 μm and the nickel content is 12.51%.
[0042] The coating thickness of the electroplated workpiece without adding the above stabilizer is 9.26 μm and the nickel content is 18.64%.
[0043] The above examples further show that the present invention has no adverse effects on the original performance of the electroplating solution. On the basis of not changing the original coating performance, it can further stably maintain the nickel content in the coating at about 13%. It can fully meet the requirements in current production applications.
[0044] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.
Claims
1. A stabilizer for nickel content in a non-cyanide alkaline zinc-nickel alloy coating, characterized in that: By mass concentration, the concentrations of the components in the stabilizer are: 4-hydroxypyridine 30-50 g / L, ethyl carbamate 30-50 g / L, and quinamide alcohol 3-5 g / L.
2. The stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating according to claim 1, characterized in that: By mass ratio, the ratio of 4-hydroxypyridine, ethyl carbamate, and quinamide alcohol is 10:10:
1.
3. Use of a stabilizer for the nickel content in a non-cyanide alkaline zinc-nickel alloy coating as described in any one of claims 1-2 in the preparation of a non-cyanide alkaline zinc-nickel alloy coating.
4. Use of a stabilizer for nickel content in a non-cyanide alkaline zinc-nickel alloy coating according to claim 3 in the preparation of a non-cyanide alkaline zinc-nickel alloy coating, characterized in that: Add the described stabilizer as a component of the non-cyanide alkaline zinc-nickel alloy electroplating solution to the electroplating solution. The concentrations of the components of the stabilizer in the electroplating solution are: 4-hydroxypyridine 0.3-0.5 g / L, ethyl carbamate 0.3-0.5 g / L, and quinamide alcohol 0.03-0.05 g / L.
5. Use of a stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating according to claim 4 in the preparation of a cyanide-free alkaline zinc-nickel alloy coating, characterized in that: The electroplating solution, by mass concentration, contains the following components: 4-hydroxypyridine 0.3-0.5 g / L, ethyl carbamate 0.3-0.5 g / L, quinamide alcohol 0.03-0.05 g / L, zinc oxide 8-10 g / L, sodium hydroxide 110-140 g / L, nickel sulfate 4-5 g / L, triethanolamine 20-25 g / L, tetraethylenepentamine 5-8 g / L, tetrahydroxypropyl ethylenediamine 20-30 g / L, and DPE-3 4-6 ml / L.
6. Use of a stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating according to claim 3 in the preparation of a cyanide-free alkaline zinc-nickel alloy coating, characterized in that: The electroplating temperature range is 20 - 25 °C, the electroplating time range is 50 - 70 min, and the electroplating cathode current density range is 1.0 - 2.0 A / dm 2 , and the anode used for electroplating is an iron plate plated with semi-bright nickel or a nickel plate.
7. Use of a stabilizer for nickel content in a cyanide-free alkaline zinc-nickel alloy coating according to claim 3 in the preparation of a cyanide-free alkaline zinc-nickel alloy coating, characterized in that: During electroplating, the stirring method is cathode movement, and the movement speed is 3-10 m / min.