Tin-based lead-free solder and preparing method thereof

A lead-free solder, tin-based technology, applied in the direction of welding equipment, welding/cutting media/materials, welding media, etc., can solve the problems of low wettability, increased cost, yellowing of solder joints, etc., to achieve a durable surface mirror, Effects of saving cost and improving wetting power

Active Publication Date: 2009-08-26
宏桥新电子材料(深圳)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are many types of solder used in electronic products at present. Most of the existing lead-free solders are tin-silver, tin-copper, tin-silver-copper, tin-silver-copper-bismuth, tin-antimony-silver-copper, tin-silver Composed of copper-nickel, etc., but the above-mentioned lead-free solder still has shortcomings: high melting point, low wettability, fast oxidation, more tin slag, yellow solder joints, high cost
The above three patent applications all use Ni as one of the raw material components. Ni is a heavy metal, which is toxic and will increase the cost

Method used

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  • Tin-based lead-free solder and preparing method thereof
  • Tin-based lead-free solder and preparing method thereof
  • Tin-based lead-free solder and preparing method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The formula of the solder in this example is 99.185% tin, 0.5% silver, 0.3% copper, 0.01% phosphorus, and 0.005% gallium.

[0036] The preparation method is:

[0037] Refined tin containing 99.95% of tin and metal gallium containing 99.99% of gallium are put into the crucible for melting at a weight ratio of 97:3, heated to 870°C, kept for 3.5 hours, stirred for 40 minutes, taken out of the furnace, cooled and cast into Gallium 3% tin-gallium master alloy ingot.

[0038] Refined tin containing 99.95% tin and silver powder containing 99.99% silver are put into the crucible for smelting according to the weight ratio of the two at 90:10, heated to 1000°C, kept for 3.5 hours, stirred for 40 minutes, taken out of the furnace, cooled and cast into silver-containing 10% tin-silver master alloy ingot.

[0039] Refined tin containing 99.95% tin and refined copper containing 99.95% copper are put into the crucible for melting at a weight ratio of 70:30, heated to 870°C, kept fo...

Embodiment 2

[0043]The formula of the solder in this example is 99.599% tin, 0.1% silver, 0.1% copper, 0.001% phosphorus, and 0.2% gallium.

[0044] The preparation method is:

[0045] Refined tin containing 99.95% of tin and metal gallium containing 99.99% of gallium are put into the crucible for melting at a weight ratio of 97:3, heated to 920°C, kept for 2.8 hours, stirred for 20 minutes, taken out of the furnace, cooled and cast into a Gallium 3% tin-gallium master alloy ingot.

[0046] Put 99.95% tin-containing refined tin and 99.99% silver-containing silver powder into the crucible for smelting according to the weight ratio of the two at 90:10, heat up to 1300°C, keep warm for 2.8 hours, stir for 20 minutes, take out of the furnace, cool and cast into silver-containing 10% tin-silver master alloy ingot.

[0047] Refined tin containing 99.95% tin and refined copper containing 99.95% copper are put into the crucible for melting at a weight ratio of 70:30, heated to 920°C, kept for 2....

Embodiment 3

[0051] The formula of the solder in this example is 98.9% tin, 0.3% silver, 0.7% copper, 0.05% phosphorus, and 0.05% gallium.

[0052] The preparation method is:

[0053] Refined tin containing 99.95% of tin and metal gallium containing 99.99% of gallium are put into the crucible for melting at a weight ratio of 97:3, heated to 900°C, kept for 3 hours, stirred for 30 minutes, taken out of the furnace, cooled and cast into a Gallium 3% tin-gallium master alloy ingot.

[0054] Refined tin containing 99.95% tin and silver powder containing 99.99% silver are put into the crucible for smelting according to the weight ratio of the two at 90:10, heated to 1200°C, kept for 3 hours, stirred for 30 minutes, taken out of the furnace, cooled and cast into silver-containing 10% tin-silver master alloy ingot.

[0055] Refined tin containing 99.95% tin and refined copper containing 99.95% copper are put into the crucible for melting at a weight ratio of 70:30, heated to 900°C, kept for 3 h...

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Abstract

The invention relates to a tin-based lead-free solder and a preparing method thereof, the tin-based lead-free solder contains, based on weight percentage, 0.005-0.5% of gallium, 0.1-1% of silver, 0.1-1% of copper, 0.001-0.5% of phosphor and tin as the balance. The method for preparing the tin-based lead-free solder comprises the steps of: first of all, preparing four intermediate alloy ingots including tin-gallium, tin-silver, tin-copper and tin-phosphor; adding the four intermediate alloy ingots according to particular weight parts and then additionally adding the balancing tin; in the meantime, adding the mixture into a manganese alloy pot for melting, and heating up to 450 DEG C; discharging, cooling and casting into the lead-free solder so as to obtain the lead-free solder that contains gallium, silver, copper and phosphor with tin being the balance. The invention has the advantage that the lead-free solder is low in melting point, excellent in wettability, bright in soldering spot, persistent in anti-oxidation under high temperature operation and low in cost.

Description

technical field [0001] The invention relates to a tin-based alloy and a preparation method thereof, in particular to a tin-based lead-free solder and a preparation method thereof. Background technique [0002] Tin-lead solder is the main soldering material in electronic assembly soldering, and has been valued by people for its high-quality performance and low cost. However, it is well known that lead and its compounds are toxic substances, and human beings will bring greater harm to the living environment and safety if they are exposed to them for a long time. Among them, lead is more harmful to children and will affect their IQ and normal development. With the rapid development of the electronics industry and the higher and higher requirements for the soldering quality of electronic products, in order to avoid this problem, human beings are calling for restricting or even prohibiting the use of leaded solder. There are many types of solder used in electronic products at p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/26C22C1/03
Inventor 林世聪
Owner 宏桥新电子材料(深圳)有限公司
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