阅读说明：本技术 一种无氰电镀纳米银添加剂 (Cyanide-free electroplating nano-silver additive ) 是由 刘光明 甘鸿禹 唐荣茂 熊义 刘永强 刘欢欢 官宇 于 2020-07-13 设计创作，主要内容包括：本发明一种无氰电镀纳米银添加剂中分别含主光亮剂60~80g/L、辅助光亮剂10~20g/L、表面润湿剂5~10g/L和保护剂1~3g/L,其中主光亮剂由25%~50%的γ-丁烯内酰胺、10%~15%的聚丁烯二酰亚胺、15%~35%的δ-戊烯内酰胺、10%~15%的聚戊烯二酰亚胺和10%~15%的邻苯二甲酰亚胺组成。本发明添加剂能有效提高镀层光亮度及耐变色能力,在室温下即可达到高光亮与晶粒细化效果,镀层光亮度可达600Gu以上,晶粒可细化至纳米级；稳定性强,在长时间电镀作业或静置后仍能起到优秀的光亮效果；且生产成本低,效率高,绿色环保。(The cyanide-free electroplating nano silver additive disclosed by the invention respectively contains 60-80 g/L of main brightening agent, 10-20 g/L of auxiliary brightening agent, 5-10 g/L of surface wetting agent and 1-3 g/L of protective agent, wherein the main brightening agent consists of 25-50% of gamma-butenolide, 10-15% of polybutene diimide, 15-35% of pentenoic lactam, 10-15% of polypentene diimide and 10-15% of phthalimide. The additive can effectively improve the brightness and the discoloration resistance of the coating, can achieve high brightness and grain refinement effect at room temperature, the brightness of the coating can reach over 600Gu, and the grains can be refined to be nano-scale; the stability is strong, and the excellent brightening effect can be achieved after long-time electroplating operation or standing; and the production cost is low, the efficiency is high, and the environment is protected.)

1. The cyanide-free electroplating nano silver additive is characterized in that: the additive consists of a main brightener, an auxiliary brightener, a protective agent and a surface wetting agent, wherein the additive contains 60-80 g/L of the main brightener, 10-20 g/L of the auxiliary brightener, 5-10 g/L of the surface wetting agent and 1-3 g/L of the protective agent respectively;

the main brightening agent consists of 25-50% of gamma-butenolide, 10-15% of polybutene diimide, 15-35% of pentenyl lactam, 10-15% of polypentene diimide and 10-15% of phthalimide in percentage by mass; the auxiliary brightening agent consists of 40-50% of aminopyrimidine, 20-30% of 4-acetamidopyrimidine and 20-30% of sulfadiazine; the protective agent consists of 50-80% of sulfathiazole thioglycolic acid, 10-25% of sulfathiazole monoethanolamine and 10-25% of propane pyridinium sulfonate; the surface wetting agent consists of 30-40% of ammonium dodecyl sulfonate, 30-40% of sodium dodecyl benzene sulfonate and 30-40% of sodium dodecyl sulfate;

the preparation process of the additive comprises the following steps:

adjusting the pH value to 10-11 by using a sodium hydroxide or potassium hydroxide solution in 700 mL of pure water, sequentially adding 5-10 g of a surface wetting agent, 60-80 g of a main light agent and 10-20 g of an auxiliary brightening agent under the condition of fully and uniformly stirring, then adding a mixture of 1-3 g of a protective agent and 150mL of pure water, uniformly mixing, and continuously adding pure water until the volume of the mixture reaches 1L to obtain the cyanide-free electroplating nano-silver additive.

2. The cyanide-free electroplated nanosilver additive of claim 1, wherein: the molecular weight of the polybutylene diimide and the polypentene diimide is less than 2000.

3. The cyanide-free electroplated nanosilver additive of claim 1, wherein: the application conditions of the additive are as follows: the pH range is 7.5-11.5, and the temperature range is 10-55 ℃.

Technical Field

The invention relates to a cyanide-free electroplating nano-silver additive, which is an additive used in silver electroplating under direct current or pulse conditions in a cyanide-free plating solution, and particularly belongs to the technical field of electroplating additives.

Background

With the increasing living standard and the development of science and technology, the demand and the requirement of people on silver plating parts are increased day by day. The silver plating layer for industrial production generally adopts an electroplating means, the current mainstream silver electroplating system contains cyanide which is often extremely toxic, and the cyanide electroplating is gradually eliminated along with the enhancement of environmental protection consciousness and safety consciousness. However, in the silver electrodeposition layer prepared without any additive, it is difficult to obtain a dense and bright plating layer regardless of the plating conditions used, and a dendrite segregation phenomenon may even occur. Therefore, it is very important to develop a stable plating additive capable of effectively improving the plating state. At present, cyanide-free silver electroplating is the development direction of green electroplating, but the problems of poor glossiness, low binding force and the like exist, and cyanide electroplating is still difficult to replace. The cyanide-free bright silver plating solution mentioned in patent CN 107299367A has a current density range of 0.1-0.2A/dm²The current density of the conventional cyanide silver plating is 0.2-1.2A/dm²On the one hand, a lower current density leads to low production efficiency, and on the other hand, a narrower current density interval leads to lower yield. The alkaline cyanide-free silver plating electroplating solution and the silver plating method provided in patent CN 1073130841A have the plating temperature range of 40-60 ℃, and the plating can be carried out only by heating, so that the energy consumption in production is increased, the production cost is improved, and the production efficiency is lower. The cyanide-free bright silver plating bath mentioned in patent CN201710738117.3 gave a silver plating layer with a gloss of only 110 Gu.

Therefore, the additive of the cyanide-free silver electroplating solution, which is stable, efficient and environment-friendly, can improve the displacement capability of the plating solution, the glossiness of a silver coating and the grain refinement degree of the silver coating and widen the current density range of the plating solution at room temperature, is always a research hotspot in the field of cyanide-free silver plating.

Disclosure of Invention

The invention aims to provide a cyanide-free electroplating nano silver additive, which mainly depends on imide or lactam containing unsaturated bonds, can widen the current density range of a plating solution, effectively improve the anti-tarnishing capability and glossiness of a silver deposition layer obtained by electroplating and enable the plating layer to achieve mirror surface brightness.

The cyanide-free electroplating nano-silver additive disclosed by the invention consists of a main brightener 60-80 g/L, an auxiliary brightener 10-20 g/L, a surface wetting agent 5-10 g/L and a surface wetting agent 1-3 g/L;

the main brightening agent consists of 25-50% of gamma-butenolide, 10-15% of polybutene diimide, 15-35% of pentenyl lactam, 10-15% of polypentene diimide and 10-15% of phthalimide in percentage by mass; the auxiliary brightening agent consists of 40-50% of aminopyrimidine, 20-30% of 4-acetamidopyrimidine and 20-30% of sulfadiazine; the protective agent consists of 50-80% of sulfathiazole thioglycolic acid, 10-25% of sulfathiazole monoethanolamine and 10-25% of propane pyridinium sulfonate; the surface wetting agent consists of 30-40% of ammonium dodecyl sulfonate, 30-40% of sodium dodecyl benzene sulfonate and 30-40% of sodium dodecyl sulfate.

The preparation process of the additive comprises the following steps:

adjusting the pH value to 10-11 by using a sodium hydroxide or potassium hydroxide solution in 700 mL of pure water, sequentially adding 5-10 g of a surface wetting agent, 60-80 g of a main light agent and 10-20 g of an auxiliary brightening agent under the condition of fully and uniformly stirring, then adding a mixture of 1-3 g of a protective agent and 150mL of pure water, uniformly mixing, and continuously adding pure water until the volume of the mixture reaches 1L to obtain the cyanide-free electroplating nano-silver additive.

The molecular weight of the polybutylene diimide and the polypentene diimide is less than 2000.

The application conditions of the additive are as follows: the pH range is 7.5-11.5, and the temperature range is 10-55 ℃.

The invention has the beneficial effects that:

1. the cyanide-free electroplating nano silver additive can refine crystal grains of a plating layer and reduce internal stress of the plating layer, and mainly depends on imide or lactam of unsaturated bonds contained in the cyanide-free electroplating nano silver additive, so that the current density range of the plating solution can be widened, the anti-tarnishing capability and the glossiness of a silver deposition layer obtained by electroplating are effectively improved, the mirror surface brightness of the plating layer can be achieved, the maximum glossiness can reach more than 600Gu, the crystal grains of the plating layer can be refined to be nano-scale, and the average size is 30-80 nm.

2. The cyanide-free silver plating additive does not contain harmful cyanide components, is green and environment-friendly, belongs to the development direction of green electroplating, has strong stability, and still has good brightening effect after long-time electroplating operation or long-time standing.

3. The cyanide-free silver plating additive can play an excellent bright effect when being used for electroplating at room temperature, does not need heating in the electroplating process, and has low production cost and high efficiency.

Drawings

FIG. 1 is a diagram of a plated article obtained in a Hull cell without adding a brightener to the silver plating solution of the present invention;

FIG. 2 is a diagram of a plated article obtained in a Hull cell after addition of a cyanide-free silver plating additive in example 1 of the present invention;

FIG. 3 shows the gloss test results of the plated article obtained in a Hull cell after the cyanide-free silver plating additive was added in example 1 of the present invention;

FIG. 4 is an FESEM image of a plated article obtained in a Hell cell after a plating layer is enlarged by 10 ten thousand times after a cyanide-free silver plating additive is added in example 1 of the present invention.

Detailed Description