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Tin-lead chemically plated alloy for circuit board

A technology of electroless tin plating and lead alloy, applied in the chemical field, can solve the problems of corrosion and poisoning, and achieve the effect of reducing the corrosion of equipment

Inactive Publication Date: 2014-10-08
NINGGUO XINBONENG ELECTRONICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the toxicity of fluoboric acid to people and the corrosion of equipment make people have to improve this formula

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] An electroless tin-lead alloy for circuit boards, comprising the following components in mass percent: tin methanesulfonate 200g / l, lead methanesulfonate 80g / l, thiourea 60g / l, sodium hypophosphite 6g / l , the temperature is 60°C, and the time is 20min.

[0012] The beneficial effects of the present invention are: the present invention provides stannous and plumbous ions by tin methanesulfonate and lead methanesulfonate, and the free methanesulfonic acid in the solution controls the acidity, and the thickness of the coating can reach 5 μm or thicker. The use of methanesulfonic acid instead of fluoboric acid reduces the harm to people and the corrosion of equipment, which is safe, environmentally friendly and pollution-free.

Embodiment 2

[0014] An electroless tin-lead alloy for circuit boards, comprising the following components in mass percent: tin methanesulfonate 400g / l, lead methanesulfonate 240g / l, thiourea 100g / l, sodium hypophosphite 14g / l , the temperature is 120°C, and the time is 40min.

[0015] The beneficial effects of the present invention are: the present invention provides stannous and plumbous ions by tin methanesulfonate and lead methanesulfonate, and the free methanesulfonic acid in the solution controls the acidity, and the thickness of the coating can reach 5 μm or thicker. The use of methanesulfonic acid instead of fluoboric acid reduces the harm to people and the corrosion of equipment, which is safe, environmentally friendly and pollution-free.

Embodiment 3

[0017] An electroless tin-lead alloy for circuit boards, comprising the following components in mass percent: tin methanesulfonate 300g / l, lead methanesulfonate 160g / l, thiourea 80g / l, sodium hypophosphite 10g / l , the temperature is 90°C, and the time is 30min.

[0018] The beneficial effects of the present invention are: the present invention provides stannous and plumbous ions by tin methanesulfonate and lead methanesulfonate, and the free methanesulfonic acid in the solution controls the acidity, and the thickness of the coating can reach 5 μm or thicker. The use of methanesulfonic acid instead of fluoboric acid reduces the harm to people and the corrosion of equipment, which is safe, environmentally friendly and pollution-free.

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Abstract

The invention discloses a tin-lead chemically plated alloy for a circuit board, and is characterized by including the following components by the mass percentage: 200-400 g / L of tin methanesulfonate, 80-240 g / L of lead methanesulfonate, 60-100 g / L of thiourea, and 6-14 g / L of sodium hypophosphite; the temperature is 60-120 DEG C, and the time is 20-40 min. The preparation method has the beneficial effects that stannous ions and divalent lead ions are respectively provided by tin methanesulfonate and lead methanesulfonate, methanesulfonic acid free in a solution is used for controlling the acidity, and the thickness of a plating layer can reach 5 [mu]m or thicker; and methanesulfonic acid is adopted to replace fluoboric acid, so as to reduce poison and harm to human and corrosion to equipment, and be safe, environmentally friendly and pollution-free.

Description

technical field [0001] The invention relates to the chemical field, in particular to an electroless tin-lead alloy for circuit boards. Background technique [0002] Metal tin is widely used in the electronics industry because of its excellent corrosion resistance and solderability. Sn-lead alloys, especially those with a weight ratio of 63% tin and 37% lead, are widely used on printed circuit boards because of their lowest eutectic point (only 183°C). There are two methods of tin-lead alloy plating on printed circuit boards: electroplating and electroless plating. Since Brenner and Riddle laid the foundation of electroless nickel plating in 1944, its application range has been expanding day by day. However, electroless plating has a slow deposition rate and a relatively thin coating, which greatly limits its application. As far as electroless tin-lead plating is concerned, at present, the thickness of the plating layer can only reach 5-6 μm in China, and the thickness of ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C18/48
Inventor 罗宏强
Owner NINGGUO XINBONENG ELECTRONICS