Silver-free and lead-free solder composition
A silver lead-free solder, high-strength technology, applied in the direction of welding medium, welding equipment, welding/cutting medium/material, etc., can solve problems such as cracks or peeling of solder joints, poor bonding strength of soldering interface, insufficient wettability, etc. , to reduce costs, improve the strength and wettability of the base material, and improve the strength of the welding interface
Inactive Publication Date: 2014-05-21
ACCURUS SCI
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Problems solved by technology
However, because the aforementioned solder has low silver content or no silver, the tensile strength of the solder body (hereinafter referred to as the base material strength) is poor and the wettability is insufficient, so the strength of the internal solder joints after the substrate is soldered is relatively insufficient, and the soldering process is also difficult. It is easy to cause cracks or peeling of the solder joints after soldering due to poor wettability, and the bonding strength of the soldering interface (hereinafter referred to as the interface strength) is not good, which further causes electronic products to be reworked or scrapped
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[0011] In a preferred embodiment of the high-strength silver-free lead-free solder of the present invention, the total weight of the high-strength silver-free lead-free solder is 100wt%, and the high-strength silver-free lead-free solder includes: 2 to 8wt% of bismuth, 0.1 to 1.0wt% copper, 0.01 to 0.2wt% at least one of nickel (Ni), iron (Fe) or cobalt (Co), and the balance is tin. Using bismuth to replace the expensive silver in the previous composition can improve the strength and wettability of the substrate, thereby reaching or surpassing the performance of tin-silver-copper solder, and because it does not contain silver, the cost is greatly reduced, and the price of bismuth is lower than Pure tin is low, so the price can be more competitive than existing tin-copper solders. In addition, by adding at least one of iron, nickel, and cobalt, the interface strength of the solder alloy can be improved.
[0012] Preferably, the high-strength silver-free lead-free solder furthe...
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The invention relates to a solder composition and discloses a silver-free and lead-free solder composition, which includes 2 wt % to 8 wt % of Bi, 0.1 wt % to 1.0 wt % of Cu, 0.01 wt % to 0.2 wt % of at least one of Ni, Fe, and Co, and the balance of Sn based on 100 wt % of the silver-free and lead-free solder composition. In this invention, bismuth is used to replace silver so as to significantly reduce manufacturing costs. Moreover, the tensile strength and wetting capability are surprisingly increased, so that the solder composition of this invention provides a performance equal to or superior to that of the conventional Sn-Ag-Cu solder composition. In addition, a bonding strength could be increased by adding at least one of Ni, Fe, and Co in the solder composition of this invention.
Description
technical field [0001] The invention relates to a solder composition, in particular to a high-strength silver-free lead-free solder suitable for solder joints of electronic parts. Background technique [0002] Among the known techniques, tin-lead alloys are often used as solders for electronic parts, but due to the serious pollution of lead and its compounds to the environment, coupled with the increasing awareness of environmental protection, lead-containing solders have gradually been subject to international restrictions in recent years. Therefore, it is gradually replaced by "lead-free solder". [0003] In the application of lead-free solder, lead-free solder composed of tin-silver-copper (SAC305) and tin-copper (Sn-Cu) is the most widely used. In particular, tin-silver-copper (SAC305) is used the most. In recent years, due to the soaring price of silver, the price of tin-silver-copper alloy solder has remained high, thus increasing the packaging cost of electronic comp...
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IPC IPC(8): B23K35/24
CPCB23K35/262B23K35/0222C22C13/02
Inventor 陈添丁
Owner ACCURUS SCI