Stabilizer for electroplating brightening tin and tin alloy and preparation method thereof

Abstract

A stabilizer for electroplating brightening tin and tin alloy comprises, by weight, 100-120 parts of sodium hypophosphite, 20-30 parts of ascorbic acid, 30-40 parts of polyethylene glycol and 10-15 parts of sulfanilic acid. The molecular weight M of the polyethylene glycol is 6000-12000. A preparation method of the stabilizer for electroplating brightening tin and tin alloy includes the following steps that (a) polyethylene glycol is weighed, distilled water is added to the polyethylene glycol to form a polyethylene glycol solution with the concentration of 5-8%, and heating and stirring are conducted until the polyethylene glycol is completely dissolved; (b) sodium hypophosphite is added and stirred until the sodium hypophosphite is completely dissolved; (c) ascorbic acid is added into the solution and stirred until the ascorbic acid is completely dissolved; (d) sulfanilic acid is added into the solution and stirred until the sulfanilic acid is completely dissolved; and (e) distilled water is supplemented and added to enable the concentration of the polyethylene glycol to be 3-4%, and the operation is competed after uniform stirring. The stabilizer for electroplating brightening tin and tin alloy has the advantages of being high in corrosion resistance, good in covering capacity, good in stability, high in electroplating efficiency and capable of being stored for a long time. A tin plating solution is stable. A clad layer obtained through electroplating is uniform, compact and good in combination force.

Description

technical field [0001] The content of the present invention is to provide a stabilizer for tin and tin alloys for bright electroplating, and the present invention also provides a preparation method for the stabilizer for tin and tin alloys for bright electroplating. Background technique [0002] In the electronics industry, the requirements for bright tin plating and tin alloys are very strict. Not only should they meet the conventional requirements of good bonding force, fine and smooth crystallization, low brittleness, and good solderability, but also require the coating to be free of tin whiskers and leaks. , pinholes, and pitting; the plating solution should also have a fast deposition rate and be able to work at a higher temperature; because, if it exceeds 30°C, the solution is prone to turbidity, precipitation, Sn 4+ It is very easy to produce, and the appearance of the coating is foggy, gray spots, pinholes, pitting, and even whiskers. This will bring great harm to t...

AI Technical Summary

Problems solved by technology

[0003] In today's tin plating and tin alloy industry, divalent tin salt is mainly used for tin plating, and in the process of divalent tin tin plating, due to the introduction of raw materials and electrochemical anodic oxidation on the anode, the plating solution is extremely unstable. Can not effectively suppress the production of tetravalent tin

The more tetravalent tin ions accumulate, when they reach a certain concentration, it will cause many problems such as a decrease in cathode current efficiency, poor dispersion of the plating solution, rough coating, and tin whiskers.

However, the disadvantage is that the temperature of the plating solution is relatively low, generally only between 15-25°C, and if it exceeds 30°C, the solution is prone to turbidity, precipitation, Sn 4+ It is very easy to produce, and the appearance of the coating is foggy, gray spots, pinholes, pitting, and even whiskers.

But the obvious defect is that it is not suitable for higher liquid temperature, the consumption is too fast, and the brittleness of the coating increases, and the solderability decreases.

Images