KR20040063025A - Alloy that there is no lead ingredient for soldering - Google Patents

Abstract

PURPOSE: A Sn-Cu-Ni-P quaternary lead free alloy for soldering is provided which does not contain lead harmful to the human body, improves mechanical strength of solder, prevents cracks on a soldering part and reduces oxidation amount of solder. CONSTITUTION: The lead free alloy for soldering is characterized in that it is a Sn-Cu-Ni-P quaternary lead free alloy for soldering formed by adding phosphorus (P) to a Sn-Cu-Ni ternary lead free alloy as constituents, wherein the Sn-Cu-Ni-P quaternary lead free alloy for soldering comprises 0.2 to 0.8 wt.% of copper (Cu), 0.02 to 0.08 wt.% of nickel (Ni), 0.001 to 0.3 wt.% of phosphorus (P) and a balance of tin (Sn).

Description

Lead-Free Alloys for Soldering {Alloy that there is no lead ingredient for soldering}

The present invention relates to a lead-free alloy for soldering used in the soldering (solaring) process for fixing various components to the substrate in the production of electrical and electronic products,

More specifically, Sn-Cu not only contains Pb that is harmful to the human body, but also increases the mechanical strength of the solder, prevents cracking of the soldering site, and reduces the amount of oxidation of the solder. It relates to a lead-free alloy for brazing Ni-P solders.

In general, Sn-Pb-based solders have been most commonly used for bonding and fixing components of various electrical and electronic products to a substrate.

Such conventional solders cause cracks in soldering parts of electronic parts and the like mounted on printed circuit boards and generate a lot of oxides, which is a major cause of cold soldering and shorts, thereby deteriorating reliability of printed circuit boards such as electronic products. .

In addition, lead (Pb) contained in the solder is not only very harmful to the human body but also causes environmental pollution. Therefore, the lead and lead countries in the EU and developed countries do not use lead (Pb) in order to protect the human body and prevent environmental pollution. In order to ban all of these, legislation is actively progressing.

This movement is rapidly spreading to other neighboring countries. Accordingly, research on lead-free solders containing no lead is being actively conducted, and various lead-free alloys for soldering have been developed.

Among the lead-free alloys for soldering, many alloy compositions containing Bi or As were formed, which were relatively expensive and costly to manufacture.

When soldering electronic components, a lot of oxides were generated.

In addition, there was a disadvantage that the melting temperature is relatively high.

The present invention has been made to solve the above-mentioned conventional problems, Sn-Cu-Ni lead-free in order to solve the above problems in the soldering process used when mounting the electronic components on the printed circuit board, such as electronic products By adding phosphorus (P) to the solder alloy to produce a lead-free alloy for Sn-Cu-Ni-P soldering,

It is relatively inexpensive than the soldering alloy containing Bi or As, and removes the substance which increases the strength of general tin-lead solder and the harmful factors of the substance, increases the mechanical strength of the soda, and the solder by thermal deformation. The purpose of the present invention is to provide a high quality, high quality, harmless lead-free alloy for soldering, which prevents cracking of the ring portion and reduces oxidation, as well as improved wettability.

When explaining the present invention in detail by the embodiment for achieving the above object as follows.

The present invention is a lead-free alloy composition for Sn-Cu-Ni-P ternary brazing in which a member element is added phosphorus (P) to a Sn-Cu-Ni ternary lead-free alloy.

Here, the Sn-Cu-Ni-P ternary solderless lead-free alloy, copper (Cu) is 0.2 to 0.8% by weight, nickel (Ni) is 0.02 to 0.08% by weight, phosphorus (P) is 0.001 to 0.3 % By weight, and the remaining amount is composed of tin (Sn).

The lead-free alloy for Sn-Cu-Ni-P braided alloy of the present invention alloyed with the chemical composition as described above is a material that increases mechanical strength and the human body due to evaporation of lead generated during the soldering operation of the material. By alloying an element that can remove harmful elements, the soda process that uses lead that is harmful to the human body can be replaced, and the amount of soda oxidation can be reduced, and the copper (Cu) element of the added material has electrical resistance. In addition, the thermal strength can be improved with nickel (Ni) element.

In addition, since copper (Cu) is soldered as the same element as the conductor of the printed circuit board, the generation of intermetallic compounds at the solder joint can be minimized, so that the solder wettability is improved as well as that of the printed circuit board on which the electronic product is mounted. It is possible to extend the life of electronic products by maximizing reliability improvement.

The lead-free alloy for soldering Sn-Cu-Ni-P of the present invention alloyed with the above chemical composition is a conventional solder (chemical composition of Sn: 62 to 64% by weight, Pb: 35.784% by weight, Sb: 0.10 wt% or less, Cu: 0.03 wt% or less, Bi: 0.03 wt% or less, Zn: 0.002 wt% or less, Fe: 0.02 wt% or less, Al: 0.002 wt% or less) As a result of comparing the crack initiation rate, tensile strength, wettability, and oxidation amount, the conclusions as shown in the following table were obtained.

As described above, the lead-free alloy for soldering Sn-Cu-Ni-P of the present invention as compared with the conventional solder according to the comparative example,

In the comparative experiment of the crack incidence of the soldering portion, the lead-free alloy for soldering of the present invention was 4.5%, while the comparative example was 40%. It can be seen that the lead-free alloy for soldering of the present invention had less cracking rate of the soldering portion. .

In the comparative experiment of tensile strength at 20 ° C., the lead-free alloy for soldering of the present invention had a tensile strength of 6 kg / mm 2, while the comparative example had only 4.8 kg / mm 2. It can be seen that the strength is much stronger.

In addition, in the comparative experiments of the wettability performed at 230 ° C., the lead-free alloy for soldering of the present invention was about 4.0 seconds compared to the wettability in about 3.0 seconds, and it can be seen that the wettability of the lead-free alloy for soldering of the present invention was much better. .

On the other hand, in the comparative experiment of the amount of oxidation, the lead-free alloy for soldering of the present invention produces only about 1/4 of the oxide compared to the comparative example, and the lead-free alloy for soldering of the present invention is less oxidized, thus reducing the consumption. It can be seen that the soldering defect is very low.

As described above, the lead-free alloy for Sn-Cu-Ni-P quaternary soldering of the present invention is a printed circuit board for adding copper (Cu) and nickel (Ni) to increase the strength of tin (Sn) and reducing electrical resistance. By adding the same copper (Cu) as the alloying element of the alloy, the thermal and electrical stability is improved, and a small amount of the fourth phosphorus (P) element is added to Sn-Cu-Ni to improve wettability. It is effective in reducing the amount of oxidation.

As a result, when the lead-free alloy for Sn-Cu-Ni-P quaternary soldering of the present invention is used, the cracking rate of the soldering portion is low, the mechanical strength of the solder is high, and the generation of oxide is less, which causes the electronics on the printed circuit board. It is not only harmful to human body but also contains no lead (Pb), which is very harmful to the human body. It is a very innovative invention with various effects.

Claims (2)

A lead-free alloy for soldering, characterized in that the member is composed of a Sn-Cu-Ni-P ternary solderless lead-free alloy obtained by adding phosphorus (P) to a Sn-Cu-Ni ternary lead-free alloy. The method of claim 1, The composition ratio of the lead-free alloy for Sn-Cu-Ni-P quaternary soldering is copper (Cu) is 0.2 to 0.8% by weight, nickel (Ni) is 0.02 to 0.08% by weight, phosphorus (P) is 0.001 to 0.3 A lead-free alloy for soldering, characterized in that the weight percentage, and the remaining amount is composed of tin (Sn).