Environment-friendly and low-temperature residue-free solder paste and preparing method thereof

A technology without residue and solder paste, applied in manufacturing tools, welding equipment, metal processing equipment, etc., can solve the problems of poor weldability of Sn-Bi alloy, etc., achieve less residue after soldering, promote wetting, and transparent residue after soldering Effect

Active Publication Date: 2017-08-25
中山翰华锡业有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In actual production, there are copper, aluminum, iron and other parts on the surface of electronic components for welding. It is necessary to complete the welding of these parts under the condition that the overall melting point of the solder paste is not high, and the overall welding temperature cannot be too high. Under the circumstances, the melting point of Sn-Bi eutectic solder is 138°C, which is the main choice, which only meets the requirements of soldering temperature, and Bi is an alloy element that is easily oxidized, so the flux of the solder paste is required to have a certain inhibitory effect on its oxidation. At the same time, it is necessary to improve the defect of poor weldability of Sn-Bi alloy

Method used

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  • Environment-friendly and low-temperature residue-free solder paste and preparing method thereof
  • Environment-friendly and low-temperature residue-free solder paste and preparing method thereof
  • Environment-friendly and low-temperature residue-free solder paste and preparing method thereof

Examples

Experimental program
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Effect test

Embodiment 1～6

[0032] The preparation method of embodiment 1~6 is as follows:

[0033] Table 1: The solder paste composition ratio of Examples 1-6

[0034]

[0035] Table 2: Component distribution ratio of flux in the solder paste of Examples 1-6

[0036]

[0037]

Embodiment 1

[0039] A. Mix the activator and carrier evenly in proportion, and heat to 110°C to completely dissolve to make primary mixture a, cool to room temperature for later use;

[0040] B. Mix the film-forming agent and the surfactant evenly, and heat to 105°C to completely dissolve to obtain the primary mixture b;

[0041] C. Add corrosion inhibitor to the primary mixture b, stir to dissolve completely and cool to room temperature, then add the above primary mixture a, stir evenly to make flux, and place it in an environment with a temperature of 2°C for later use;

[0042] D. After the prepared flux is left to stand for 24 hours, add Sn-Bi solder powder and the third element alloy powder except aluminum powder according to the weight ratio, mix and stir in the vacuum disperser at 125°C for 3.7H, and cool down After reaching 45°C, add nano-aluminum powder and stir evenly, and refrigerate at 4°C to obtain a finished solder paste.

Embodiment 2

[0044] A. Mix the activator and the carrier evenly in proportion, and heat to 120°C to completely dissolve to make primary mixture a, cool to room temperature for later use;

[0045] B. Mix the film-forming agent and the surfactant evenly, and heat to 100°C to completely dissolve to obtain the primary mixture b;

[0046] C. Add corrosion inhibitor to the primary mixture b, stir to dissolve completely and cool to room temperature, then add the above primary mixture a, stir evenly to make flux, and place it in an environment with a temperature of 2°C for later use;

[0047]D. After the prepared flux is left to stand for 24 hours, add Sn-Bi solder powder and the third element alloy powder except aluminum powder according to the weight ratio, mix and stir and evaporate in the vacuum disperser at 135°C for 4H, and cool down to After 45°C, add nano-aluminum powder and stir evenly, and refrigerate at 1°C to obtain a finished solder paste.

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Abstract

The invention relates to environment-friendly and low-temperature residue-free solder paste and a preparing method thereof. According to the technical scheme, the environment-friendly and low-temperature residue-free solder paste is characterized in that the solder paste comprises, by weight, 41.0%-60.0% of Sn, 26.6%-37.7% of Bi, 2.1%-4.4% of a third element alloy and 9.0%-19.0% of scaling powder; and the scaling powder comprises, by weight, 67.0%-75.0% of a carrier, 14.8%-18.8% of an activating agent, 4.6%-8.72% of a thixotropic agent, 0.32%-3.2% of a surface active agent and 1.48%-3.5% of corrosion inhibitor. The environment-friendly and low-temperature residue-free solder paste is provided, halogen-free components are adopted in a formula, volatile components are avoided in the tin paste, and smells are avoided during using. After welding, residues are colorless and transparent, and the effect of replacing Pb containing tin paste or halogen-containing tin paste is achieved. Under the low-temperature welding condition, nano aluminum powder is added, a high-temperature solid solution is formed during welding to serve as an auxiliary part for supplementary welding, poor welding of a Sn-Bi alloy is effectively improved, and the welding requirement for aluminum components on the surface of an electronic component can be met; and meanwhile, the storage period of the tin paste is prolonged, and better wettability is brought.

Description

[0001] 【Technical field】 [0002] The invention relates to the technical field of solder paste and its preparation, in particular to an environment-friendly low-temperature residue-free solder paste and a preparation method thereof. [0003] 【Background technique】 [0004] Solder is a fusible metal with a melting point lower than the melting point of the metal to be welded. When the solder melts, it can wet the surface of the metal to be welded without melting the metal to be welded, and form an alloy layer at the contact surface to bond with the metal to be welded. Connected together, the solder paste is made by mixing solder and flux together. When soldering, the solder paste is first applied to the printed circuit board and then soldered. It is widely used in the production process of electrical and electronic products. At present, the solder paste prepared with lead-free alloy solder such as SnAgCu, SnAg, etc. generally has a reflow temperature above 230°C. However, the ope...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/26B23K35/36
CPCB23K35/262B23K35/3613
Inventor 龙斌马鑫万国晖周建林展羽童桂辉张春慧李幼成
Owner 中山翰华锡业有限公司
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