阅读说明：本技术 中性锡电镀液 (Neutral tin electroplating solution ) 是由 李盛 于 2018-09-10 设计创作，主要内容包括：本发明公开了一种中性锡电镀液,包括以下浓度的各物质：锡盐25-60g/L、导电剂50-250g/L、络合剂50-300g/L、添加剂10-100mL/L；所述络合剂为羧酸或羧酸盐；所述添加剂由以下浓度物质的水溶液组成：聚氧丙烯醚0.01-0.5g/L、四级铵盐R<Sub>4</Sub>NX 0.1-5g/L,所述R为C<Sub>1-20</Sub>烷基、C<Sub>1-20</Sub>芳基或C<Sub>1-20</Sub>芳烷基,所述X为卤素负离子、硫酸脂负离子、磷酸酯负离子。本发明的中性锡电镀液中的添加剂能够有效的抑制粘片及凝聚现象,粘片率低于1％,且在电镀的过程中无气泡产生,电镀液的消泡性能好；本发明各组分之间的协同作用避免了Sn<Sup>2+</Sup>的水解,提高了电镀液的透明度及稳定性。(The invention discloses neutral tin electroplating solution, which comprises the following substances in concentration: 25-60g/L of tin salt, 50-250g/L of conductive agent, 50-300g/L of complexing agent and 10-100mL/L of additive; the complexing agent is carboxylic acid or carboxylate; the additive consists of an aqueous solution of the following substances in concentration: 0.01-0.5g/L of polyoxypropylene ether and quaternary ammonium salt R 4 NX0.1-5g/L, R is C 1‑20 Alkyl radical, C 1‑20 Aryl or C 1‑20 And the X is halogen anion, sulfate anion or phosphate anion. The additive in the neutral tin electroplating solution can effectively inhibit sticking and coagulation phenomena, the sticking rate is lower than 1%, no bubble is generated in the electroplating process, and the defoaming performance of the electroplating solution is good; the synergistic effect among the components of the invention avoids Sn 2+ The transparency and the stability of the electroplating solution are improved.)

1. A neutral tin plating solution comprising the following concentrations of each: 25-60g/L of tin salt, 50-250g/L of conductive agent, 50-300g/L of complexing agent and 10-100mL/L of additive;

the complexing agent is carboxylic acid or carboxylate;

the additive consists of an aqueous solution of the following substances in concentration: 0.01-0.5g/L of polyoxypropylene ether and quaternary ammonium salt R₄NX0.1-5g/L, R is C_1-20Alkyl radical, C_1-20Aryl or C_1-20And the X is halogen anion, sulfate anion or phosphate anion.

2. The neutral tin plating solution of claim 1 comprising the following concentrations of each: 40g/L of tin salt, 150/L of conductive agent, 200g/L of complexing agent and 30mL/L of additive.

3. The neutral tin plating solution of claim 1 wherein the tin salt is a tin alkyl sulfonate.

4. The neutral tin plating solution according to claim 1, wherein the carboxylic acid of the complexing agent is at least two hydroxycarboxylic acids and the carboxylic acid salt is at least two hydroxycarboxylic acid salts.

5. The neutral tin plating solution according to claim 1, wherein said conductive agent is an ammonium sulfide salt.

6. The neutral tin plating solution of claim 5 wherein said sulfide ammonium salt is an organosulfide ammonium salt.

7. The neutral tin plating solution according to claim 1, wherein the concentration of said first reagent is 50 to 200g/L and the concentration of said second reagent is 0.5 to 100 g/L.

8. The neutral tin plating solution according to claim 7, wherein the concentration of said carboxylic acid is 50 to 200g/L and the concentration of said carboxylic acid salt is 50 to 200 g/L.

Technical Field

The invention relates to the technical field of metal surface electroplating treatment, in particular to a tin electroplating solution.

Background

Tin is chemically stable, resistant to oxidation in the atmosphere and not prone to discoloration, does not react with sulfides, and hardly reacts with dilute solutions of sulfuric acid, hydrochloric acid, nitric acid, and some organic acids, so that tin plating processes are widely used industrially. The tin coating has the advantages of good stability, corrosion resistance, strong anti-tarnishing capability, non-toxic coating and the like, and has good weldability and ductility.

At present, the tin plating solution used in industry mainly adopts an acid electroplating system, and the common acid electroplating systems include a sulfate plating solution, a fluoborate plating solution and a chloride-fluoride plating solution. Among them, the main disadvantages of sulfate plating solutions are that whiskers are likely to grow on the plating layer, the internal stress of the plating layer is difficult to control, and the stability of the plating solution is poor. The fluoborate plating solution has good plating solution dispersibility, fine and high brightness of the plating layer, high weldability, but high cost and pollution to the environment, so the use is limited. The chloride-fluoride plating solution is a high-speed tin plating solution, is mainly used for high-speed electroplating of strips, and cannot be widely applied due to corrosion of chloride ions on equipment and pollution of fluoride ions on the environment.

Based on the defects, some manufacturers independently develop some neutral electroplating additives, but the defoaming property and the oxidation resistance of the electroplating solution and the thickness uniformity and the weldability of the electroplating film are poor, so that the use requirements of high-end users cannot be met.

Disclosure of Invention

The invention aims to provide a neutral tin electroplating solution, which can solve the problems of poor defoaming property, poor oxidation resistance, easy adhesion of sheets, poor thickness uniformity of an electroplating film and poor weldability of the neutral tin electroplating solution.

In order to solve the problems, the invention adopts the following technical scheme:

the invention provides neutral tin electroplating solution, which comprises the following substances in concentration: 25-60g/L of tin salt, 50-250g/L of conductive agent, 50-300g/L of complexing agent and 10-100mL/L of additive;

the complexing agent is carboxylic acid or carboxylate;

the additive consists of an aqueous solution of the following substances in concentration: 0.01-0.5g/L of polyoxypropylene ether and quaternary ammonium salt R₄NX0.1-5g/L, R is C_1-20Alkyl radical, C_1-20Aryl or C_1-20And the X is halogen anion, sulfate anion or phosphate anion.

Still further, the following concentrations of each were included: 40g/L of tin salt, 150/L of conductive agent, 200g/L of complexing agent and 30mL/L of additive.

Still further, the tin salt is a tin alkyl sulfonate.

Still further, the carboxylic acid in the complexing agent is a hydroxycarboxylic acid and the carboxylate is a salt of a hydroxycarboxylic acid.

Still further, the conductive agent is a sulfide ammonium salt.

Still further, the sulfide ammonium salt is an organosulfide ammonium salt.

Furthermore, the concentration of the first reagent is 50-200g/L, and the concentration of the second reagent is 0.5-100 g/L.

Further, the concentration of the carboxylic acid is 50 to 200g/L, and the concentration of the carboxylate is 50 to 200 g/L.

The invention has the following beneficial effects:

(1) the additive in the neutral tin electroplating solution can effectively inhibit sticking and coagulation, the sticking rate is lower than 1 percent, no bubble is generated in the electroplating process, and the defoaming performance of the electroplating solution is good.

(2) The neutral tin electroplating solution does not contain heavy metals such as fluoborate, lead, bismuth and the like, has low treatment cost, does not cause pollution to the environment, and meets the requirements of safety and environmental protection.

(3) The electroplating film formed by electroplating the neutral tin electroplating solution has good thickness uniformity and good weldability.

(4) The neutral tin electroplating solution has good dispersibility of each component, and the synergistic effect of the components avoids Sn²⁺The transparency and the stability of the electroplating solution are improved.

Detailed Description