A cadmium electroplating process with high dispersibility and no hydrogen embrittlement effect

Abstract

The present invention provides a cadmium electroplating process method with high dispersibility and no hydrogen embrittlement effect. The method comprises the following steps: (1) adding sodium acetate and cadmium acetate to ethylene glycol liquid; (2) heating the mixture in (1) while performing magnetic stirring to form a clear and transparent liquid; (3) adding ammonium chloride to the liquid in (2); (4) adding ethanol to the liquid in (3) and continuing stirring for a period of time; (5) controlling the liquid temperature to decrease and maintain; (6) electroplating with a cadmium plate as an anode and a workpiece to be plated as a cathode; (7) taking out the plated workpiece and washing and drying it with ethanol. The present invention reduces the viscosity of the ionic liquid by adding ethanol with low viscosity and completely miscible with ethylene glycol, thereby improving the dispersibility of the plating solution, and at the same time adding an appropriate amount of ammonium chloride to compensate for the decrease in conductivity caused by the addition of ethanol, and finally achieving cadmium electroplating with high dispersibility and no hydrogen embrittlement effect.

Description

Technical Field

[0001] The invention relates to an electroplating process method, in particular to an electroplating cadmium process method with high dispersibility and no hydrogen embrittlement effect. Background Art

[0002] Electroplating cadmium is a traditional surface protection technology for steel materials. Although the toxicity of metal cadmium limits its application, its corrosion resistance in salt spray environments is significantly stronger than other traditional metal protective layers, so it still plays an irreplaceable role in the fields of ocean, aerospace, etc. However, electroplating cadmium in aqueous solution is generally accompanied by a strong hydrogen evolution reaction, which can easily cause hydrogen embrittlement of steel materials. This has also become a major technical bottleneck in the electroplating protection of steel materials, especially ultra-high-strength high-speed iron materials.

[0003] Electroplating in non-aqueous solution can avoid the occurrence of hydrogen evolution reaction. Room temperature ionic liquid is a new type of electrolyte with potential, and electrodeposition of various metals and alloys has been achieved in it. However, this type of liquid generally has a large viscosity, which makes its dispersion ability weak and difficult to meet the needs of actual production. Summary of the invention

[0004] Based on this, it is necessary to provide a process method for electroplating cadmium with high dispersibility in a room temperature ionic liquid solution without hydrogen embrittlement effect in order to solve the above problems.

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

[0006] A cadmium electroplating process method with high dispersibility and no hydrogen embrittlement effect, the method comprising the following steps:

[0007] (1) adding sodium acetate and cadmium acetate to ethylene glycol liquid to obtain a mixture;

[0008] (2) heating the mixture in step (1) while magnetically stirring it to form a clear and transparent liquid;

[0009] (3) adding ammonium chloride to the clear and transparent liquid in step (2) to obtain a mixed liquid;

[0010] (4) adding ethanol to the mixed liquid in step (3) and continuing stirring for a period of time;

[0011] (5) controlling the temperature of the liquid obtained in step (4) to decrease and maintain the temperature;

[0012] (6) Electroplating is performed using the cadmium plate as the anode and the workpiece to be plated as the cathode;

[0013] (7) Take out the plated parts and clean and dry them with ethanol;

[0014] Furthermore, in step (1), the amount of sodium acetate added is 0.25-0.5 mol / L, and the amount of cadmium acetate added is 0.1-0.75 mol / L;

[0015] Furthermore, in the step (2), the heating temperature is ≥80°C and the stirring time is not less than 2 hours.

[0016] Furthermore, in step (3), the amount of ammonium chloride added is 0.1-0.5 mol / L.

[0017] Furthermore, in step (4), the amount of ethanol added is determined by the volume of ethylene glycol in step (1), and the volume ratio of ethanol to ethylene glycol is 1:2 to 1:10.

[0018] Furthermore, in step (5), the temperature is lowered and controlled at 40-55°C.

[0019] Furthermore, in step (6), the cathode current density is 0.2-1.0 A / dm 2 .

[0020] The electroplating process method of cadmium with high dispersibility and without hydrogen embrittlement effect of the present invention reduces the viscosity of the ionic liquid by using ethanol, which has low viscosity and is completely miscible with ethylene glycol as an additive, thereby improving its dispersibility. At the same time, the addition of ammonium chloride makes up for the decrease in solution conductivity caused by the addition of ethanol, and finally realizes the electroplating of cadmium with high dispersibility in the room temperature ionic liquid without hydrogen embrittlement effect. Implementation

[0021] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to embodiments, but the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0023] The present invention provides a cadmium electroplating process method with high dispersibility and no hydrogen embrittlement effect, comprising the following steps:

[0024] (1) adding sodium acetate and cadmium acetate to ethylene glycol liquid to obtain a mixture;

[0025] (2) heating the mixture in step (1) while magnetically stirring it to form a clear and transparent liquid;

[0026] (3) adding ammonium chloride to the clear and transparent liquid in step (2) to obtain a mixed liquid;

[0027] (4) adding ethanol to the mixed liquid in step (3) and continuing stirring for a period of time;

[0028] (5) controlling the temperature of the liquid obtained in step (4) to decrease and maintain the temperature;

[0029] (6) Electroplating is performed using the cadmium plate as the anode and the workpiece to be plated as the cathode;

[0030] (7) Remove the plated parts and clean and dry them with ethanol.

[0031] Furthermore, in step (1), the amount of sodium ethoxide added is 0.25-0.5 mol / L, and the amount of cadmium acetate added is 0.1-0.75 mol / L.

[0032] Furthermore, in the step (2), the heating temperature is ≥80°C and the stirring time is not less than 2 hours.

[0033] Furthermore, in step (3), the amount of ammonium chloride added is 0.1-0.5 mol / L.

[0034] Furthermore, in step (4), the amount of ethanol added is determined by the volume of ethylene glycol in step (1), and the volume ratio of ethanol to ethylene glycol is 1:2 to 1:10.

[0035] Furthermore, in step (5), the temperature is lowered and controlled at 40-55°C.

[0036] Furthermore, in step (6), the cathode current density is 0.2-1.0 A / dm 2 .

[0037] The electroplating process method of cadmium with high dispersibility and without hydrogen embrittlement effect of the present invention reduces the viscosity of the ionic liquid by using ethanol, which has low viscosity and is completely miscible with ethylene glycol as an additive, thereby improving its dispersibility. At the same time, the addition of ammonium chloride makes up for the decrease in solution conductivity caused by the addition of ethanol, and finally realizes the electroplating of cadmium with high dispersibility in the room temperature ionic liquid without hydrogen embrittlement effect. Example 1

[0038] The present invention provides a cadmium electroplating process method with high dispersibility and no hydrogen embrittlement effect, wherein the addition of ethanol is the main reason for reducing the viscosity of the room temperature ionic liquid plating solution and thus improving the dispersibility, which is illustrated by Example 1 and comprises the following steps:

[0039] (1) Add 0.5 mol sodium acetate and 0.5 mol cadmium acetate to 1 L ethylene glycol, heat and stir at 85 °C in an oil bath for 2.5 h to obtain a transparent liquid.

[0040] (2) Add 0.2 mol of ammonium chloride;

[0041] (3) Divide the above solution into two beakers, with 500 mL of solution in each beaker. Add 100 mL of ethanol to one of the solutions and continue stirring for 0.5 hours.

[0042] (4) Control the temperature of the two cups of solution to drop and maintain at 50°C;

[0043] (5) Electroplating was performed in the above solutions without or with ethanol, using T91 steel sheet as substrate and cadmium plate as anode. Only one anode was used during electroplating, with one side of the sample facing the anode and the other side facing away from the anode. The cathode current density was 0.5 A / dm 2 ;

[0044] (6) After 1 hour, remove the sample, wash it with ethanol and blow it dry.

[0045] By comparison, it was found that the color and thickness distribution of the coating on the side facing the anode of the test piece electroplated in the solution without ethanol added were seriously uneven, while more than 80% of the surface of the side facing away from the anode was not covered with coating. However, the entire test piece electroplated in the solution with ethanol added was completely covered with coating. The comparison shows that the addition of ethanol can significantly improve the dispersion ability of the plating solution. Example 2

[0046] The addition of ammonium chloride is to make up for the decrease in solution conductivity caused by the addition of ethanol, thereby further improving the quality of the coating, which is illustrated by Example 2, comprising the following steps:

[0047] (1) Add 0.5 mol sodium acetate and 0.5 mol cadmium acetate to 1 L ethylene glycol, heat and stir at 85 °C in an oil bath for 2.5 h to obtain a transparent liquid.

[0048] (2) Divide the above solution into two beakers, with 500 mL of solution in each beaker. Add 0.1 mol of ammonium chloride to one of the beakers.

[0049] (3) Add 100 mL of ethanol to each of the two beakers and continue stirring for 0.5 hours;

[0050] (4) Control the temperature of the two cups of solution to drop and maintain at 45°C;

[0051] (5) Electroplating was performed in the above solutions without or with ethanol, using T91 steel sheet as substrate and cadmium plate as anode. Only one anode was used during electroplating, with one side of the sample facing the anode and the other side facing away from the anode. The cathode current density was 1 A / dm 2 ;

[0052] (6) After 0.5 hours, remove the sample, wash it with ethanol and blow it dry.

[0053] By comparison, it can be found that the coating color of the test piece surface in the solution without ammonium chloride is unevenly distributed, and the coating is obviously dark as a whole, while the coating of the test piece surface in the solution with ammonium chloride presents a uniform gray-white metallic color.

[0054] The above only describes the specific embodiments of the present invention, but cannot be regarded as the protection scope of the present invention. Any equivalent changes or modifications made according to the design spirit of the present invention should be considered to fall within the protection scope of the present invention.

Claims

1. A cadmium electroplating process with high dispersibility and no hydrogen embrittlement effect, characterized in that: The method comprises the following steps: (1) adding sodium acetate and cadmium acetate to ethylene glycol liquid to obtain a mixture; (2) heating the mixture in step (1) while magnetically stirring it to form a clear and transparent liquid; (3) adding ammonium chloride to the clear and transparent liquid in step (2) to obtain a mixed liquid; (4) adding ethanol to the mixed liquid in step (3) and continuing stirring for a period of time; (5) controlling the temperature of the liquid obtained in step (4) to decrease and maintain the temperature; (6) In the above liquid, electroplating is performed with the cadmium plate as the anode and the workpiece to be plated as the cathode; (7) Remove the plated parts, clean them with ethanol and dry them.

2. A cadmium electroplating process with high dispersibility and no hydrogen embrittlement effect according to claim 1, characterized in that: In the step (1), the amount of sodium acetate added is 0.25-0.5 mol / L, and the amount of cadmium acetate added is 0.1-0.75 mol / L.

3. A cadmium electroplating process with high dispersibility and no hydrogen embrittlement effect according to claim 1, characterized in that: In the step (2), the heating temperature is ≥80°C and the stirring time is not less than 2 hours.

4. A cadmium electroplating process with high dispersibility and no hydrogen embrittlement effect according to claim 1, characterized in that: In the step (3), the amount of ammonium chloride added is 0.1 to 0.5 mol / L.

5. The method of electroplating cadmium with high dispersibility and without hydrogen embrittlement effect according to claim 1, characterized in that: In the step (4), the amount of ethanol added is determined by the volume of ethylene glycol in the step (1), and the volume ratio of ethanol to ethylene glycol is 1:2 to 1:

10.

6. The method of electroplating cadmium with high dispersibility and no hydrogen embrittlement effect according to claim 1, characterized in that: In the step (5), the temperature is lowered and controlled at 40-55°C.

7. The method of electroplating cadmium with high dispersibility and without hydrogen embrittlement effect according to claim 1, characterized in that: In the step (6), the cathode current density is 0.2 to 1.0 A / dm.