阅读说明：本技术 一种无氰镀银光亮剂及其制备方法 (Cyanide-free silver plating brightener and preparation method thereof ) 是由 田志斌 许荣国 詹益腾 于 2020-07-13 设计创作，主要内容包括：本发明涉及无氰镀银技术领域,具体涉及一种无氰镀银光亮剂及其制备方法,以去离子水为溶剂,包含下述浓度的组分：十二烷基二苯磺酸钠10～25g/L、HEDTA 1～2.5g/L、稳定剂0.5～2.0g/L、分散剂20～35g/L、尿素10～20g/L、1-苄基-1,2,3,4-四氢异喹啉10～15g/L、含硫杂环化合物30～45g/L。本发明无氰镀银光亮剂可以改变镀层的晶体取向,显著细化晶粒,获得的镀层耐磨性、光亮效果明显,不容易受电流密度大小的影响。(The invention relates to the technical field of cyanide-free silver plating, in particular to a cyanide-free silver plating brightener and a preparation method thereof, wherein deionized water is used as a solvent, and the brightener comprises the following components in concentration: 10-25 g/L, HEDTA 1-2.5 g/L of sodium dodecyl diphenyl sulfonate, 0.5-2.0 g/L of stabilizer, 20-35 g/L of dispersant, 10-20 g/L of urea, 10-15 g/L of 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline and 30-45 g/L of sulfur-containing heterocyclic compound. The cyanide-free silver plating brightener can change the crystal orientation of a plating layer, obviously refines crystal grains, and obtains the plating layer with obvious wear resistance and bright effect, which is not easily influenced by the current density.)

1. The cyanide-free silver plating brightener is characterized in that deionized water is used as a solvent, and the brightener comprises the following components in concentration: 10-25 g/L, HEDTA 1-2.5 g/L of sodium dodecyl diphenyl sulfonate, 0.5-2.0 g/L of stabilizer, 20-35 g/L of dispersant, 10-20 g/L of urea, 10-15 g/L of 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline and 30-45 g/L of sulfur-containing heterocyclic compound.

2. The cyanide-free silver plating brightener according to claim 1, wherein deionized water is used as a solvent, and the component comprises the following components in concentration: 10g/L, HEDTA1g/L of sodium dodecyl diphenyl sulfonate, 0.5g/L of stabilizer, 20g/L of dispersant, 10g/L of urea, 10g/L of 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline and 30g/L of sulfur-containing heterocyclic compound.

3. The cyanide-free silver plating brightener according to claim 1, wherein deionized water is used as a solvent, and the component comprises the following components in concentration: 12g/L, HEDTA1g/L of sodium dodecyl diphenyl sulfonate, 1g/L of stabilizer, 28g/L of dispersant, 12g/L of urea, 14g/L of 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline and 38g/L of sulfur-containing heterocyclic compound.

4. The cyanide-free silver plating brightener according to claim 1, wherein deionized water is used as a solvent, and the component comprises the following components in concentration: 25g/L, HEDTA 2.5.5 g/L of sodium dodecyl diphenyl sulfonate, 2.0g/L of stabilizer, 35g/L of dispersant, 20g/L of urea, 15g/L of 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline and 45g/L of sulfur-containing heterocyclic compound.

5. The cyanide-free silver plating brightener according to claim 1, wherein the stabilizer comprises at least one of potassium dihydrogen phosphate, citric acid, and potassium sorbate.

6. The cyanide-free silver plating brightener according to claim 1, wherein the dispersant comprises beta-naphthol polyoxyethylene ether and polyethylene glycol.

7. The cyanide-free silver plating brightener as claimed in claim 6, wherein the mass ratio of the beta-naphthol polyoxyethylene ether to the polyethylene glycol is 1: (0.5 to 1).

8. The cyanide-free silver plating brightener according to claim 1, wherein the sulfur-containing heterocyclic compound comprises one or more of 2-methyltetrahydrofuran-3-thiol, 2-isobutylpyrazine, 2-methoxythiazole, 2-ethoxythiazole, and pyrazineethylthiol.

9. The cyanide-free silver plating brightener according to claim 8, wherein the sulfur-containing heterocyclic compound is 2-methyltetrahydrofuran-3-thiol.

10. A method for preparing a cyanide-free silver plating brightener as claimed in any one of claims 1 to 9, comprising the steps of:

s1, weighing sodium dodecyl benzene sulfonate, a dispersing agent and HEDTA in a formula amount, adding into deionized water, and stirring until the sodium dodecyl benzene sulfonate, the dispersing agent and the HEDTA are completely dissolved to obtain a mixture A;

s2, heating to 40-50 ℃, measuring the sulfur-containing heterocyclic compound, the stabilizer and the urea 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline according to the formula amount, and stirring and dissolving to obtain a mixture B;

s3, adding the mixture B in the step S2 into the mixture A in the step S1, exhausting for 4-5min, and continuing stirring for 20-25min under inert gas to obtain the cyanide-free silver plating brightener.

Technical Field

The invention relates to the technical field of cyanide-free silver plating, in particular to a cyanide-free silver plating brightener and a preparation method thereof.

Background

Because silver has the characteristics of softness, easy polishing, convenient soldering, good conductivity, stable chemical property and the like, the electroplated silver occupies an extremely important position in the electronic industry and the manufacturing industry of instruments and meters, and has good decorative effect in daily life. With the increasing living standard and the rapid development of high-tech information industry, people have increasing demand for silver plating, especially bright silver plating.

The practical application system of the electro-silvering can be divided into cyanide silvering and cyanide-free silvering. Compared with cyanide silver plating, the development of cyanide-free silver plating is only a matter of decades, and processes such as thiosulfate plating, iminodisulfonic acid argentum plating, sulfosalicylic acid argentum plating, sulfite argentum plating, ferrous thiocyanate argentum plating, potassium pyrophosphate argentum plating, butanediimide argentum plating, potassium thiocyanate argentum plating, glim nicotinate plating solution argentum plating, isonicotinic acid argentum plating and the like are successively proposed, the first cyanide-free argentum plating patent in the U.S. is a plating solution using hydrabamine as a complexing agent, and the U.S. patent in 2001 proposes that organic sulfide and organic carboxylic acid are used as brightening agents in alkylsulfonic acid, alkylsulfthalimide or alkylsulfthalimide cyanide-free argentum plating solutions; in 2005, silver nitrate-thiosulfate silver plating was studied, electroplating was carried out in a pulse mode, and a mirror bright coating with a smooth surface, high corrosion resistance and strong bonding force with a substrate was obtained from a mixture of diaminothiourea, phenanthroline, sodium dodecyl diphenyl ether sulfonate, fluorocarbon surfactant and polyethylene glycol as a brightening agent. However, in practical application, the domestic cyanide-free silver plating brightener is used for a cyanide-free silver plating system taking 5, 5-dimethylhydantoin as a complexing agent, and the plating appearance is poor and the appearance is not bright, so that the improvement space is provided.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the cyanide-free silver plating brightener which can change the crystal orientation of a plating layer, obviously refine crystal grains, and obtain the plating layer with better wear resistance and obvious brightening effect.

The above object of the present invention is achieved by the following technical solutions:

the cyanide-free silver plating brightener takes deionized water as a solvent and comprises the following components in concentration: 10-25 g/L, HEDTA 1-2.5 g/L of sodium dodecyl diphenyl sulfonate, 0.5-2.0 g/L of stabilizer, 20-35 g/L of dispersant, 10-20 g/L of urea, 10-15 g/L of 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline and 30-45 g/L of sulfur-containing heterocyclic compound.

Preferably, deionized water is used as a solvent, and the following components are contained in the following concentrations: 10g/L, HEDTA1g/L of sodium dodecyl diphenyl sulfonate, 0.5g/L of stabilizing agent, 20g/L of dispersing agent, 10g/L of urea, 10g/L of 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline and 30g/L of sulfur-containing heterocyclic compound.

Preferably, deionized water is used as a solvent, and the following components are contained in the following concentrations: 12g/L, HEDTA1g/L of sodium dodecyl diphenyl sulfonate, 1g/L of stabilizer, 28g/L of dispersant, 12g/L of urea, 14g/L of 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline and 38g/L of sulfur-containing heterocyclic compound.

Preferably, deionized water is used as a solvent, and the following components are contained in the following concentrations: 25g/L of sodium dodecyl diphenyl sulfonate, 2.5g/L of HEDTA2, 2.0g/L of stabilizer, 35g/L of dispersant, 20g/L of urea, 15g/L of 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline and 45g/L of sulfur-containing heterocyclic compound.

Preferably, the stabilizer comprises at least one of potassium dihydrogen phosphate, citric acid and potassium sorbate.

Preferably, the dispersant comprises beta-naphthol polyoxyethylene ether and polyethylene glycol.

Preferably, the mass ratio of the beta-naphthol polyoxyethylene ether to the polyethylene glycol is 1: (0.5 to 1).

Preferably, the sulfur-containing heterocyclic compound comprises one or more of 2-methyltetrahydrofuran-3-thiol, 2-isobutylpyrazine, 2-methoxythiazole, 2-ethoxythiazole and pyrazinethiol.

More preferably, the sulfur-containing heterocyclic compound is 2-methyltetrahydrofuran-3-thiol.

The invention also provides a preparation method of the cyanide-free silver plating brightener, which comprises the following steps:

s1, weighing sodium dodecyl benzene sulfonate, a dispersing agent and HEDTA in a formula amount, adding into deionized water, and stirring until the sodium dodecyl benzene sulfonate, the dispersing agent and the HEDTA are completely dissolved to obtain a mixture A;

s2, heating to 40-50 ℃, measuring the sulfur-containing heterocyclic compound, the stabilizer, the urea and the 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline according to the formula amount, and stirring to dissolve to obtain a mixture B;

s3, adding the mixture B in the step S2 into the mixture A in the step S1, exhausting for 4-5min, and continuing stirring for 20-25min under inert gas to obtain the cyanide-free silver plating brightener.

Preferably, the stirring speed of the step S1 is 100-200r/min, and the stirring time is 20-25 min; the step S2 is performed at a stirring speed of 150-.

In the cyanide-free silver plating brightener, the sulfur-containing heterocyclic compound plays a main brightening role, but small molecular sulfides generated by the decomposition of the sulfur-containing heterocyclic compound on an electrode easily enter a plating layer, so that the nucleation process and the preferred orientation of the plating layer are obviously changed, the plating layer is easy to discolor, and the mechanical property is also reduced, in order to improve the situation, the inventor finds that after 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline is added, the crystal preferred orientation of the plating layer prepared by the cyanide-free silver plating brightener is easy to adsorb on the surface of the silver electrode along the (111) crystal face and the 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline is easy to adsorb on the surface of the silver electrode to form the preferred orientation along the (111) crystal face, and the 1-benzyl-1 is added, the 2,3, 4-tetrahydroisoquinoline can refine grains, and the grain refining effect is best after the polyethylene glycol is added, presumably because the polyethylene glycol treats the 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline, the supercooling degree is improved, the growth of grains is inhibited, and the grains of the plating layer are refined. In addition, the plating layer obtained by the cyanide-free silver plating brightener has good wear resistance and obvious brightening effect, and is not easily influenced by current density.

The sodium dodecyl benzene sulfonate is used as wetting agent of cyanide-free silver plating brightener to assist dissolution and wetting in the plating solution, so that the plating layer presents mirror bright appearance, the surface tension is reduced, and the generation of plating layer pinholes is reduced.

In summary, the invention has the following beneficial technical effects:

the invention provides a cyanide-free silver plating brightener, which is characterized in that 1-benzyl-1, 2,3, 4-tetrahydroisoquinoline and polyethylene glycol are added into a brightening system, so that the crystal orientation of a plating layer is changed, crystal grains are obviously refined, the wear resistance of the plating layer is better, and the brightening effect is obvious.

Detailed Description

The present invention will be described in further detail below.