Nickel-free ferrous tin-cobalt alloy plating solution and process for utilizing plating solution for electroplating

Abstract

The present invention relates to a nickel-free ferrous tin-cobalt alloy plating solution and a process for utilizing the plating solution for electroplating. The plating solution comprises the following compositions: 0.2 to 6 g / L of tin, 0.6 to 4 g / L of cobalt, 8 to 180 g / L of complexant, 2 to 20 g / L of melanizing agent and 50 to 320 g / L of pH buffer. The parameters of the plating solution are as follows: the Baume of the plating solution is between 10 and 25 baume degrees; the temperature is between 28 and 48 DEG C; and the pH is between 10 and 13. The coating of the nickel-free ferrous tin-cobalt alloy plating solution is an alloy layer taking the tin as a main material, and a small amount of cobalt is added into the coating to form a binary alloy system; the cobalt content in a general ferrous tin-cobalt alloy plating solution exceeds 8 g / L, but the novel electroplating process can reduce the cobalt content to 0.8 g / L; and due to adoption of the special biodegradable stable complexant and the special biodegradable pH buffer, the production cost can be reduced, novel EU standards can be reached simultaneously, and various problems of the prior ferrous tin-cobalt alloy plating solution and the prior process can be solved.

Description

technical field [0001] The invention relates to the technical field of alloy electroplating, in particular to a nickel-free black tin-cobalt alloy plating solution and an electroplating process using the plating solution. This technology is suitable for hardware parts, electronic products, personal digital products, clothing accessories, children's toys, jewelry, furniture, food utensils and other items that are in close contact with the human body. Background technique [0002] At present, the tin-cobalt alloy electroplating process has been widely used in the electroplating of hardware parts, electronic products, personal digital products, clothing accessories, children's toys, jewelry, furniture, food utensils and other items and accessories. The tin-cobalt alloy coating is used to obtain a black bright alloy environmental protection layer, which meets the market demand for black electroplating decorations. The current tin-cobalt alloy electroplating process generally ha...

AI Technical Summary

Problems solved by technology

The common tin-cobalt alloy electroplating process at this stage has the following problems: 1. The cobalt content exceeds 5g / L, generally 8g / L, and the cost of the plating solution is high

4. The Baume of the plating solution is as high as 24°, the viscosity of the plating solution is high, the water is serious, and a large amount of cobalt, tin metal ions and potassium pyrophosphate are lost, which increases the cost meaninglessly; the electroplating temperature is high, and energy is wasted

5. Cobalt has certain radioactivity. (For example, cobalt 60 is a nuclear radiation substance). The 15 highly concerned substances in the EU REACH directive, which came into effect on June 1, 2007, include the requirements for cobalt chloride, which requires limiting the amount of cobalt

6. The plating solution is difficult to control, and the effect in the low current area is not good, often missing plating and yellowing. Even if the worker has a high level of technology, the plating solution needs to be adjusted frequently, resulting in waste of raw materials

7. It is difficult to control the depth and color of the plating layer, and the composition of the plating solution is adjusted entirely based on experience

8. Due to the poor effect in the low-current area of ​​the coating, when producing black and white mandarin duck-color effects without nickel and black nickel, the electroplating time is long, the coating in the high-current area is very thick, and the time for drawing and rubbing is very long, so the thickness of the underlying coating is required to be very thick , a lot of waste

[0003] Although the current black tin-cobalt alloy electroplating process can meet the EU and U.S. food standards about prohibiting the inclusion of heavy metals in the electroplating layer, the cobalt content in the plating solution is too high, which may not meet the requirements of future environmental protection electroplating, and The cost of the whole electroplating system is high