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Corrosion-resistant and wettability-perfect lead-free solder and preparation method thereof

A lead-free solder, wettability technology, applied in the direction of welding equipment, welding/cutting medium/material, welding medium, etc., can solve the problems of corrosion resistance not meeting the use requirements, solder joint corrosion damage, rough surface, etc. Achieve the effects of excellent physical and mechanical properties, refine grain structure and improve corrosion resistance

Active Publication Date: 2017-09-19
GUANGXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, under various soldering conditions, the wettability of Sn-Cu solder is not as good as that of traditional Sn-Pb solder
Especially in reflow soldering, due to the poor wettability of Sn-Cu solder, the surface is rough and the texture is more obvious, which limits the wide use of Sn-Cu solder
On the other hand, when electronic products are exposed to humid atmospheres or corrosive media in industrial environments, solder joints are often the most severely damaged by corrosion, which leads to premature failure of products
However, the corrosion resistance of the current Sn-Cu eutectic solder in a corrosive environment still cannot meet the ideal requirements for use.

Method used

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  • Corrosion-resistant and wettability-perfect lead-free solder and preparation method thereof
  • Corrosion-resistant and wettability-perfect lead-free solder and preparation method thereof
  • Corrosion-resistant and wettability-perfect lead-free solder and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] 1. Preparation of Sn-Cu-Al matrix alloy

[0024] (1) Weigh respectively 0.75wt% of Cu powder and 0.075wt% of Al powder according to the weight percentage, and the balance is Sn powder, put them into a ball mill jar, vacuumize the ball mill jar and fill it with argon, and use the following parameters for ball milling and mixing : Speed ​​90r / min, ball-to-material ratio 10:1, ball milling time 25min. Press the mixed powder into tablets with a pressure of 10MPa and hold the pressure for 5 minutes, then put the metal tablets into a non-consumable vacuum electric arc furnace with a pre-vacuum degree of 4×10 -3 Pa, then filled with high-purity argon, and started melting, the melting voltage was 220V, the melting current was controlled at 1A, and the melting time was kept at 50s to obtain a Sn-Cu-Al matrix alloy. This alloy is designated as Sample 1.

[0025] 2. Performance testing

[0026] The polarization curve of sample 1 was tested with an electrochemical workstation, t...

Embodiment 2

[0029] 1. Preparation of lead-free solder with good corrosion resistance and wettability

[0030] (1) Weigh respectively 0.5wt% of Cu powder and 0.08wt% of Al powder according to the weight percentage, and the balance is Sn powder, put them into a ball mill jar, vacuumize the ball mill jar and fill it with argon, and use the following parameters for ball milling and mixing : Speed ​​150r / min, ball-to-material ratio 10:1, ball milling time 20min. Press the mixed powder into tablets with a pressure of 12 MPa and a holding time of 10 minutes, then put the metal tablets into a non-consumable vacuum electric arc furnace with a pre-vacuum degree of 6×10 -3 Pa, and then fill it with high-purity argon, start melting, the melting voltage is 220V, the melting current is controlled at 2A, the melting time is kept at 30s, and the Sn-Cu-Al matrix alloy is obtained.

[0031] (2) According to the weight percentage of 22.02wt%, 77.98wt%, respectively weigh blocky Sn and blocky rare earth Ce,...

Embodiment 3

[0037] 1. Preparation of lead-free solder with good corrosion resistance and wettability

[0038] (1) Weigh respectively 0.75wt% of Cu powder and 0.075wt% of Al powder according to the weight percentage, and the balance is Sn powder, put them into a ball mill jar, vacuumize the ball mill jar and fill it with argon, and use the following parameters for ball milling and mixing : Speed ​​90r / min, ball-to-material ratio 10:1, ball milling time 25min. Press the mixed powder into tablets with a pressure of 10MPa and hold the pressure for 5 minutes, then put the metal tablets into a non-consumable vacuum electric arc furnace with a pre-vacuum degree of 4×10 -3 Pa, and then fill it with high-purity argon, start melting, the melting voltage is 220V, the melting current is controlled at 1A, and the melting time is kept at 60s to obtain the Sn-Cu-Al matrix alloy.

[0039] (2) According to the weight percentage of 22.02wt%, 77.98wt%, respectively weigh blocky Sn and blocky rare earth Ce,...

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Abstract

The invention provides a corrosion-resistant and wettability-perfect lead-free solder and a preparation method thereof. The solder is mainly composed of, by weight, 0.5-0.8% of Cu, 0.05-0.08% of Al, 0.10-0.50% of rare earth and the balance Sn. The preparation method comprises the steps that firstly, tin powder, copper powder and aluminum powder are weighed according to percentage to be subjected to ball mill mixing, then tabletting is conducted, and finally Sn-Cu-Al substrate alloy is obtained through smelting; secondly, tin and the rare earth are weighed according to designed compositions, and an intermediate alloy is prepared through smelting; and finally, the substrate alloy and the intermediate alloy are weighed according to designed compositions, and put into a non-self-consuming vacuum electric-arc furnace to be smelted, and the corrosion-resistant and wettability-perfect lead-free solder is prepared. According to the corrosion-resistant and wettability-perfect lead-free solder and the preparation method thereof, rare earth elements are added into a Sn-Cu series, a dense corrosion product passive film is formed on an alloy surface, the corrosion resistance of the solder is enhanced, and the wettability of an alloy is enhanced at the same time.

Description

technical field [0001] The invention belongs to the technical field of lead-free solder, in particular to a preparation method of Sn-Cu series lead-free solder alloy. Background technique [0002] With the requirements of environmental protection, lead-free solder has become an important solder, which is an environmentally friendly material, and the research and development of lead-free solder needs to consider whether it meets the requirements of performance from the following aspects: 1) low melting point; 2) suitable Electrical conductivity, thermal conductivity, thermal expansion coefficient and other physical properties; 3) Good wettability with existing component substrates, leads and PCB materials; 4) Sufficient mechanical properties: shear strength, creep resistance, isothermal fatigue resistance , Thermal fatigue resistance, stability of metallographic structure. In addition to meeting performance requirements, the development of new lead-free solders also needs to...

Claims

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Application Information

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IPC IPC(8): C22C13/00C22C1/03B23K35/26
Inventor 湛永钟杜再翔杨文超李吉东吴凯峰黄金芳陈晓娴叶海梅吴俊彦张建锋
Owner GUANGXI UNIV
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