CN106222710A - A kind of acid half bright tin plating solution and preparation method thereof - Google Patents

Abstract

Invention describes a kind of acid half bright tin plating solution and preparation method thereof, belong to field of material surface treatment.Component and the content thereof of solution of the present invention are as follows: stannous sulfate 20 40g/L, sulphuric acid 80 110mL/L, benzylideneacetone 0.1 0.5g/L, OP 10 2 4mL/L, NP 10 1.5 3mL/L, sodium benzoate 0.9 1.5g/L, nicotinic acid 0.1 0.25g/L, gelatin 1 4g/L, ferrous sulfate 2 3g/L, ascorbic acid 0.5 1g/L, antimony potassium tartrate 0.5 1g/L, remaining is water.The solution dispersibility of the present invention and covering power are good, operating temperature range and cathode-current density wide ranges, and plating weldability is good, and adhesion is strong, and does not adds carcinogen Beta Naphthol 99MIN and poisonous aldehydes, and to human body and environmentally friendly, and cost reduces.

Description

A kind of acid semi-bright tin plating solution and preparation method thereof

technical field

The invention relates to an acidic semi-bright tin plating solution and a preparation method thereof, belonging to the technical field of tin plating.

Background technique

Acid tin plating is an electroplating process developed in the 1960s. Tin plating has the advantages of low toxicity, good environmental performance, fast deposition speed, high current efficiency and good corrosion resistance, and has gradually been popularized and applied at home and abroad. According to the brightness of the coating, acid tin plating can be divided into bright coating and semi-bright coating. The latter is also known as dark tin, matte tin and matt tin. Compared with the former, the semi-bright tin coating has excellent reliability. It is suitable as a solderable coating for various electronic components. Good dispersion ability, while taking into account the appearance of the assembly, can also reduce the irritation of the operator's eyes from the high light during installation.

The commonly used acidic semi-bright tin plating process is divided into two types: sulfuric acid type and sulfonic acid type. The latter plating solution has good stability and high current density, and is suitable for high-speed electroplating, but the cost of the plating solution is high. In contrast, although the stability of the former is relatively low, its cost is low, and it has excellent coverage and dispersion capabilities. The plating solution does not contain lead and other harmful substances. Coatings are widely used.

The existing acid brightening technology is very mature, and there are many related literature reports at home and abroad, but there are few literature reports on semi-bright tin plating. Wherein the most classic formula is that NACHTMAN announced a kind of continuous tin plating process of steel strip in US2240265 in 1941, and its electroplating solution consists of cresol sulfonic acid, β-naphthol and animal glue. The electroplating solution of this patent has been used until now, and it is the standard electroplating solution currently used to obtain a semi-gloss coating. In addition, there are a few semi-bright tin plating processes, all of which are suitable for sulfuric acid-phenolsulfonic acid or methanesulfonic acid systems, while the semi-bright tin plating process with sulfuric acid as the dispersion medium is relatively rare. Phenolsulfonic acid has the pollution problem of phenolic compounds, so the plating solution using it as the dispersion medium is gradually being eliminated. However, the cost of the methanesulfonate system plating solution is relatively high. In addition, β-naphthol is still the main additive in the current semi-bright tin plating solution, but studies have shown that this substance is a potentially dangerous carcinogen, so it should be used less or not in the plating solution. Therefore, it is necessary to develop a semi-bright tin plating solution using sulfuric acid as a dispersion medium without using β-naphthol.

Contents of the invention

The object of the present invention is to provide a kind of acid semi-bright tin plating solution, the component and content of described acid semi-bright tin plating solution are: stannous sulfate is 20-40g/L, sulfuric acid is 80-110mL/L, benzylidene Acetone is 0.1-0.5g/L, OP-10 is 2-4mL/L, NP-10 is 1.5-3mL/L, sodium benzoate is 0.9-1.5g/L, niacin is 0.1-0.25g/L, gelatin 1-4g/L, ferrous sulfate 2-3g/L, ascorbic acid 0.5-1g/L, antimony potassium tartrate 0.5-1g/L, and the rest is water.

Another object of the present invention is to provide the preparation method of described acidic semi-bright tin plating solution, specifically comprising the following steps:

(1) Add sulfuric acid (commercially available 98% concentrated sulfuric acid) into water, cool to room temperature, then add stannous sulfate, stir to dissolve completely;

(2) Add niacin, gelatin and antimony potassium tartrate into water to dissolve completely;

(3) Add sodium benzoate, ferrous sulfate and ascorbic acid into water, and stir well to dissolve them completely;

(4) Add benzylidene acetone to the mixed solution of OP-10 and NP-10, stir to dissolve completely, then add water to stir to make it completely transparent, and then cool to room temperature;

(5) Add the solution obtained in steps (2), (3) and (4) to the solution obtained in step (1), stir well to make it evenly mixed, and then add water to the required volume to obtain acidic semi-bright tinning solution.

In step (2), in order to speed up the dissolution rate, the water can be heated to 50°C-60°C.

During the dissolution process in step (4), heat with a 50°C-60°C water bath.

The stannous sulfate, sulfuric acid, benzylidene acetone, sodium benzoate, nicotinic acid, NP-10, OP-10, gelatin, ferrous sulfate, ascorbic acid, antimony potassium tartrate are commercially available analytical pure chemical reagents described in the present invention.

Beneficial effects of the present invention: the acidic semi-bright tin plating solution of the present invention has good dispersing ability and covering ability, wide working temperature range and cathode current density range, good weldability of the plating layer, strong binding force, and no carcinogens added β-naphthol and toxic aldehydes are harmless to human body and environment, and because the added reagent is non-toxic, the raw materials are easy to obtain and the price is cheap, which reduces the production cost to a certain extent.

detailed description

The present invention will be further described below in conjunction with specific embodiments, but without departing from the core of the present invention, any simple deformation, modification or other equivalent replacements that those skilled in the art can do without creative labor all fall within the scope of the present invention. protected range.

Example 1

The components and contents of the acidic semi-bright tin plating solution in this embodiment are: 20 g/L of stannous sulfate, 80 mL/L of sulfuric acid, 0.1 g/L of benzylidene acetone, 2 mL/L of OP-10, and 1.5 mL/L of NP-10 , sodium benzoate 0.9g/L, niacin 0.1g/L, gelatin 1g/L, ferrous sulfate 2g/L, ascorbic acid 0.5g/L, antimony potassium tartrate 0.5g/L, and the rest is pure water.

Take 1L as a unit to prepare the acidic semi-bright tin plating solution described in this embodiment, and the specific steps are as follows:

(1) Take a clean beaker, add 400mL of pure water, slowly add 80mL of sulfuric acid into the water, and cool to room temperature.

(2) Add 20g of stannous sulfate in step (1), and stir until completely dissolved.

(3) Take a clean 10mL graduated cylinder, add 2mL of OP-10, 1.5mL of NP-10 and 0.1g of benzylidene acetone, heat in a water bath at 58°C, wait until the benzylidene acetone is completely dissolved, add it to a beaker filled with 100mL of pure water , heated in a water bath at 58°C until it was completely transparent, and then cooled to room temperature.

(4) Take a clean beaker, add 20mL of pure water, add 0.9g of sodium benzoate into the beaker, and stir until completely dissolved.

(5) Take a clean beaker, add 30mL of pure water, add 2g of ferrous sulfate into the beaker, stir until completely dissolved.

(6) Take a clean beaker, add 50mL of pure water, take 0.5g of ascorbic acid into the beaker, stir until completely dissolved.

(7) Take a clean beaker, add 50mL of pure water, add 0.1g of nicotinic acid into the beaker, heat in a water bath at 58°C, and stir until it is completely dissolved, then cool to room temperature.

(8) Take a clean beaker, add 50mL of pure water, add 1g of gelatin into the beaker, heat in a water bath at 58°C, and stir until it is completely dissolved, then cool to room temperature.

(9) Take a clean beaker, add 50mL of pure water, add 0.5g of antimony potassium tartrate into the beaker, heat in a water bath at 58°C, and stir until it is completely dissolved, then cool to room temperature.

(10) Add the solution obtained in step (3) (4) (5) (6) (7) (8) (9) to the solution obtained in step (2), stir well to make it evenly mixed, and then add water to set When the volume reaches 1L, an acidic semi-bright tin plating solution can be obtained.

The experiment was carried out in a 250mL Hull tank for 5 minutes, the anode was a tin plate, the cathode was a copper plate, the current density was 1A/dm ² , and the temperature was room temperature.

The electroplating process flow is:

Grinding→water washing→pickling (30-50ml sulfuric acid/L, 10-15s)→water washing→electroplating→water washing→drying.

The surface of the coating after electroplating with the electroplating solution prepared in this example is smooth, semi-bright, free of defects such as blisters, pits, and partial absence of coating; the plated parts are immersed in flux, and then dipped in molten tin at a temperature of 250 ° C. 5s, take out the plated surface, 97% of the new tin layer (required ≥95%), no bubbles and pinholes, good welding performance; use a hard steel scratch knife to draw two 2mm deep spots on the surface of the plated piece The parallel lines of the base body, the coating between the two scribed lines does not fall off, and the bonding force is strong.

Example 2

The components and contents of the present embodiment acidic semi-bright tin plating solution are: stannous sulfate 40g/L, sulfuric acid 110mL/L, benzylidene acetone 0.5g/L, OP-10 4mL/L, NP-10 3mL/L, Sodium benzoate 1.5g/L, niacin 0.25g/L, gelatin 4g/L, ferrous sulfate 3g/L, ascorbic acid 1g/L, antimony potassium tartrate 1g/L, and the rest is pure water.

Take 1L as a unit to prepare the acidic semi-bright tin plating solution described in this embodiment, and the specific steps are as follows:

(1) Take a clean beaker, add 400mL of pure water, slowly add 110mL of sulfuric acid into the water, and cool to room temperature.

(2) Add 20g of stannous sulfate in step (1), and stir until completely dissolved.

(3) Take a clean 10mL graduated cylinder, add 3mL of NP-10, 4mL of OP-10 and 0.5g of benzylidene acetone, heat in a water bath at 58°C, wait until the benzylidene acetone is completely dissolved, add it to a beaker filled with 100mL of pure water, Heat in a water bath at 58°C until it is completely transparent, then cool to room temperature.

(4) Take a clean beaker, add 20mL of pure water, take 1.5g of sodium benzoate into the beaker, stir until completely dissolved.

(5) Take a clean beaker, add 30mL of pure water, add 3g of ferrous sulfate into the beaker, stir until completely dissolved.

(6) Take a clean beaker, add 50mL of pure water, take 1g of ascorbic acid into the beaker, stir until completely dissolved.

(7) Take a clean beaker, add 50mL of pure water, add 0.25g of nicotinic acid into the beaker, heat in a water bath at 58°C, and stir until it is completely dissolved, then cool to room temperature.

(8) Take a clean beaker, add 50mL of pure water, add 4g of gelatin into the beaker, heat in a water bath at 58°C, and stir until it is completely dissolved, then cool to room temperature.

(9) Take a clean beaker, add 50mL of pure water, add 1g of antimony potassium tartrate into the beaker, heat in a water bath at 58°C, and stir until it is completely dissolved, then cool to room temperature.

(10) Add the solution obtained in step (3) (4) (5) (6) (7) (8) (9) to the solution obtained in step (2), stir well to make it evenly mixed, and then add water to set When the volume reaches 1L, an acidic semi-bright tin plating solution can be obtained.

The experiment was carried out in a 250mL Hull tank for 5 minutes, the anode was a tin plate, the cathode was a copper plate, the current density was 1A/dm ² , and the temperature was room temperature.

The electroplating process flow is:

Grinding→water washing→pickling (30-50ml sulfuric acid/L, 10-15s)→water washing→electroplating→water washing→drying.

The surface of the coating after electroplating with the electroplating solution prepared in this example is smooth, semi-bright, free of defects such as blisters, pits, and partial absence of coating; the plated parts are immersed in flux, and then dipped in molten tin at a temperature of 250 ° C. 5s, take out the plated surface, 96% of the new tin layer (required ≥ 95%), no bubbles and pinholes, good welding performance; use a hard steel scratch knife to draw two 2mm deep spots on the surface of the plated piece The parallel lines of the base body, the coating between the two scribed lines does not fall off, and the bonding force is strong.

Example 3

The components and contents of the acidic semi-bright tin plating solution in this embodiment are: 30 g/L of stannous sulfate, 100 mL/L of sulfuric acid, 0.3 g/L of benzylidene acetone, 3 mL/L of OP-10, and 2.5 mL/L of NP-10 , sodium benzoate 1.2g/L, niacin 0.2g/L, gelatin 2g/L, ferrous sulfate 2.5g/L, ascorbic acid 0.8g/L, antimony potassium tartrate 0.7g/L, and the rest is pure water.

Take 1L as a unit to prepare the acidic semi-bright tin plating solution described in this embodiment, and the specific steps are as follows:

(1) Take a clean beaker, add 400mL of pure water, slowly add 100mL of sulfuric acid into the water, and cool to room temperature.

(2) Add 30g of stannous sulfate in step (1), and stir until completely dissolved.

(3) Take a clean 10mL graduated cylinder, add 2.5mL of NP-10, 3mL of OP-10 and 0.3g of benzylidene acetone, heat in a water bath at 58°C, wait until the benzylidene acetone is completely dissolved, add it to a beaker filled with 100mL of pure water , heated in a water bath at 58°C until it was completely transparent, and then cooled to room temperature.

(4) Take a clean beaker, add 20mL of pure water, take 1.2g of sodium benzoate into the beaker, stir until completely dissolved.

(5) Take a clean beaker, add 30mL of pure water, add 2.5g of ferrous sulfate into the beaker, stir until completely dissolved.

(6) Take a clean beaker, add 50mL of pure water, take 0.8g of ascorbic acid into the beaker, stir until completely dissolved.

(7) Take a clean beaker, add 50mL of pure water, add 0.2g of nicotinic acid into the beaker, heat in a water bath at 58°C, and stir until it is completely dissolved, then cool to room temperature.

(8) Take a clean beaker, add 50mL of pure water, add 2g of gelatin into the beaker, heat in a water bath at 58°C, and stir until it is completely dissolved, then cool to room temperature.

(9) Take a clean beaker, add 50mL of pure water, add 0.7g of potassium antimony tartrate into the beaker, heat in a water bath at 58°C, and stir until it is completely dissolved, then cool to room temperature.

(10) Add the solution obtained in step (3) (4) (5) (6) (7) (8) (9) to the solution obtained in step (2), stir well to make it evenly mixed, and then add water to set When the volume reaches 1L, an acidic semi-bright tin plating solution can be obtained.

The experiment was carried out in a 250mL Hull tank for 5 minutes, the anode was a tin plate, the cathode was a copper plate, the current density was 1A/dm ² , and the temperature was room temperature.

The electroplating process flow is:

Grinding→water washing→pickling (30-50ml sulfuric acid/L, 10-15s)→water washing→electroplating→water washing→drying.

The surface of the coating after electroplating with the electroplating solution prepared in this example is smooth, semi-bright, free of defects such as blisters, pits, and partial absence of coating; the plated parts are immersed in flux, and then dipped in molten tin at a temperature of 250 ° C. 5s, take out the plated surface, 99% of the new tin layer (required ≥95%), no bubbles and pinholes, good welding performance; use a hard steel scratch knife to draw two 2mm deep spots on the surface of the plated piece The parallel lines of the base body, the coating between the two scribed lines does not fall off, and the bonding force is strong.

Claims (2)

1. An acidic semi-bright tin plating solution is characterized in that: the components and content of the acidic semi-bright tin plating solution are: stannous sulfate is 20-40g/L, sulfuric acid is 80-110mL/L, benzylidene Acetone is 0.1-0.5g/L, OP-10 is 2-4mL/L, NP-10 is 1.5-3mL/L, sodium benzoate is 0.9-1.5g/L, niacin is 0.1-0.25g/L, gelatin 1-4g/L, ferrous sulfate 2-3g/L, ascorbic acid 0.5-1g/L, antimony potassium tartrate 0.5-1g/L, and the rest is water. 2. a preparation method of acid semi-bright tin plating solution as claimed in claim 1, is characterized in that, specifically comprises the following steps: (1) Add sulfuric acid into water, cool to room temperature, then add stannous sulfate, stir to dissolve completely; (2) Add niacin, gelatin and antimony potassium tartrate into water to dissolve completely; (3) Add sodium benzoate, ferrous sulfate and ascorbic acid into water, and stir well to dissolve them completely; (4) Add benzylidene acetone to the mixed solution of OP-10 and NP-10, stir to dissolve completely, then add water to stir to make it completely transparent, and then cool to room temperature; (5) Add the solution obtained in steps (2), (3) and (4) to the solution obtained in step (1), stir well to make it evenly mixed, and then add water to the required volume to obtain acidic semi-bright tinning solution.