CA2540486A1 - Pb-free solder alloy compositions comprising essentially tin (sn), silver (ag), copper (cu), nickel (ni), phosphorus (p) and/or rare earth: cerium (ce) or lanthanum (la) - Google Patents
Pb-free solder alloy compositions comprising essentially tin (sn), silver (ag), copper (cu), nickel (ni), phosphorus (p) and/or rare earth: cerium (ce) or lanthanum (la) Download PDFInfo
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- CA2540486A1 CA2540486A1 CA 2540486 CA2540486A CA2540486A1 CA 2540486 A1 CA2540486 A1 CA 2540486A1 CA 2540486 CA2540486 CA 2540486 CA 2540486 A CA2540486 A CA 2540486A CA 2540486 A1 CA2540486 A1 CA 2540486A1
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- weight
- solder
- free solder
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- electrical conductor
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- 229910000679 solder Inorganic materials 0.000 title claims abstract description 95
- 239000000203 mixture Substances 0.000 title claims abstract description 43
- 229910052709 silver Inorganic materials 0.000 title claims abstract description 23
- 229910052684 Cerium Inorganic materials 0.000 title claims abstract description 22
- 229910052746 lanthanum Inorganic materials 0.000 title claims abstract description 22
- 229910052802 copper Inorganic materials 0.000 title claims abstract description 21
- 229910052698 phosphorus Inorganic materials 0.000 title claims abstract description 19
- 229910052759 nickel Inorganic materials 0.000 title claims abstract description 18
- 229910045601 alloy Inorganic materials 0.000 title abstract description 14
- 239000000956 alloy Substances 0.000 title abstract description 14
- 229910052761 rare earth metal Inorganic materials 0.000 title abstract description 4
- 150000002910 rare earth metals Chemical class 0.000 title abstract description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 title description 22
- 239000010949 copper Substances 0.000 title description 20
- 229910052718 tin Inorganic materials 0.000 title description 16
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 title description 4
- 239000004332 silver Substances 0.000 title description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 title description 3
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 title description 3
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 title description 3
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 title description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title description 2
- 239000011574 phosphorus Substances 0.000 title description 2
- 239000004020 conductor Substances 0.000 claims description 18
- 239000012535 impurity Substances 0.000 claims description 8
- 238000005476 soldering Methods 0.000 abstract description 10
- 230000008018 melting Effects 0.000 abstract description 9
- 238000002844 melting Methods 0.000 abstract description 9
- 238000000034 method Methods 0.000 abstract description 7
- 230000007613 environmental effect Effects 0.000 abstract description 6
- 230000008569 process Effects 0.000 abstract description 4
- 229910018100 Ni-Sn Inorganic materials 0.000 abstract description 2
- 229910018532 Ni—Sn Inorganic materials 0.000 abstract description 2
- 150000001875 compounds Chemical class 0.000 abstract description 2
- 239000013078 crystal Substances 0.000 abstract description 2
- 229910052751 metal Inorganic materials 0.000 abstract description 2
- 239000002184 metal Substances 0.000 abstract description 2
- 239000000758 substrate Substances 0.000 abstract description 2
- 231100000252 nontoxic Toxicity 0.000 abstract 1
- 230000003000 nontoxic effect Effects 0.000 abstract 1
- 239000011135 tin Substances 0.000 description 30
- 229910000831 Steel Inorganic materials 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- 230000008901 benefit Effects 0.000 description 4
- 229910000765 intermetallic Inorganic materials 0.000 description 4
- 229910052745 lead Inorganic materials 0.000 description 4
- 229910020816 Sn Pb Inorganic materials 0.000 description 3
- 229910020922 Sn-Pb Inorganic materials 0.000 description 3
- 229910008783 Sn—Pb Inorganic materials 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 230000005496 eutectics Effects 0.000 description 3
- 229910017944 Ag—Cu Inorganic materials 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 2
- 229910052797 bismuth Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- 238000009428 plumbing Methods 0.000 description 2
- 239000010944 silver (metal) Substances 0.000 description 2
- 238000009736 wetting Methods 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 229910017755 Cu-Sn Inorganic materials 0.000 description 1
- 229910018082 Cu3Sn Inorganic materials 0.000 description 1
- 229910017927 Cu—Sn Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000013043 chemical agent Substances 0.000 description 1
- 230000002860 competitive effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 231100000989 no adverse effect Toxicity 0.000 description 1
- 230000001473 noxious effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 229940100890 silver compound Drugs 0.000 description 1
- 150000003379 silver compounds Chemical class 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
- B23K35/262—Sn as the principal constituent
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
Abstract
A Pb-free solder alloy is designed from the Sn based substrate, which is a non-toxic and environmental friendly metal. The Pb-free solder includes a composition consisting essentially of 0.3 - 0.4 weight % Ag, 0.6 - 0.7 weight % Cu, 0.01 - 1.0 weight % Ni, 0.01 - 0.3 weight % P, optionally 0.001 - 0.3 weight % Ce, or 0.001 - 0.3 weight %
La, and a balance of Sn, having off-eutectic melting temperatures of about 221-233 degree Celsius.
Addition of Ni forms fine crystal texture, or forms Ni-Sn compounds, thereby improving strength and thermal fatigue characteristic. Furthermore, 0.001 - 0.3 weight %
Trace amount of Ce and / or La rare earth added to the said composition, to enhance better micro-structural stability and to reduce the coarse Sn grains in the microstructure of the solder joint formed, during Hand Soldering, Wave Soldering and Reflow Soldering in Electronics Assembly Processes.
La, and a balance of Sn, having off-eutectic melting temperatures of about 221-233 degree Celsius.
Addition of Ni forms fine crystal texture, or forms Ni-Sn compounds, thereby improving strength and thermal fatigue characteristic. Furthermore, 0.001 - 0.3 weight %
Trace amount of Ce and / or La rare earth added to the said composition, to enhance better micro-structural stability and to reduce the coarse Sn grains in the microstructure of the solder joint formed, during Hand Soldering, Wave Soldering and Reflow Soldering in Electronics Assembly Processes.
Description
Pb-free Solder Alloy Compositions Comprising Essentially Tin (Sn), Silver (AM, Copper (Cu), Nickel (Ni), Phosphorus (P) and/or Rare Earth: Cerium (Ce) or Lanthanum (La) Background of the Invention 1. Field of the Invention Despite Pb is a component of solder alloys in widespread use in the electronic industry, there is a drive to replace the use of Pb metal, because of its toxic nature. In addition to the toxicity of Pb, there are other problems concerning continued widespread use of the Sn-Pb and Pb-based solders. In United States, Canada, most of the Europe, and in Japan, the use of Pb in all commercial products, such as: vehicles, electronic toys, computers and appliances, shall all be banned.
2. Description of the Prior Art The excellent metallurgical wetting of 63% Sn and 37% Pb is thought to be promoted by the instantaneous formation of a thin layer of a very stable intermetallic compound at the molten solder interface. The interfacial inter-metallic compound that aids solder wetting is always based on Sn, not Pb. The role of Pb in promoting solderability is much less understood, but seems related to its ability to strongly suppress the liquid surface tension of the solder alloy, lowering the contact angel of the molten solder which leads to better spreading and more interacting surface area for the solder joint to form. The eutectic solidification reaction of 63% Sn and 37% Pb also generates a highly refined mixture of Sn and Pb phases that produces unusual strength from rather weak constituents.
In response to the possibility of a governmental ban or excessive taxation of Pb use, manufacturers and users of Pb-bearing solder for electronic and circuit joining applications recently have attempted to developed Pb-free solders as direct replacements for the conventional Sn-Pb solders in conventional hand/wave/reflow soldering processes employing general heating of an electronic wiring board to temperatures of 240-degree Celsius. Moreover, there is a need for such a solder that would be competitive in cost and as readily available as conventional Sn-Pb eutectic solders for high volume use.
A ternary, off-eutectic Sn-Ag-Cu solder alloy has been developed by the plumbing industry as a Pb-free solder with 96 weight % Sn, 3.5 weight % Cu, and 0.5 weight % Ag. This plumbing solder has a 227 degree Celsius of solidus temperature and 260 degree Celsius liquidus temperature, which would be considered not suitable for electronics manufacturers.
Recent developments of Pb-free solder alloys mainly involve the use of Ag, Bi, Cu, In, Sn, and Zn. Special attentions have been drawn on the solder composition comprising Sn, Ag, and Cu. Anderson et. al. of Iowa State University Research have reported the eutectic Pb-free solder comprising 93.6Sn/4.7Ag/1.7Cu and Sn/Ag/Cu/Ni/Fe, respectively.
Summary of the Invention This present invention provides a Pb-free solder comprising a compositions consisting essentially of Sn, Ag, Cu, Ni, P, and/or Ce or La, having a melting temperature of 221-233 degree Celsius.
In one embodiment of the invention, the Pb-free solder consists essentially of 0.3 weight % Ag, 0.7 weight % Cu, 0.3 weight % Ni, 0.05 weight % P, 0.05 weight % Ce or La, and balance of weight % Sn. To the Sn/0.3Ag/0.7Cu/0.3Ni/0.05P, 0.05 weight % of Ce or La is added to improve better micro-structural stability and hence reduce grain size of Sn in the solder composition, and the melting temperature is 223-230 degree Celsius.
In another embodiment of the invention, the Pb-free solder consists essentially of 0.4 weight % Ag, 0.6 weight % Cu, 0.3 weight % Ni, 0.05 weight % P, 0.05 weight %
Ce or La, and balance of weight % Sn. To the Sn/0.4Ag/0.6Cu/0.3Ni/0.05P, 0.05 weight % Ce or La is added to improve better micro-structural stability and hence reduce grain size of Sn in the solder composition, and the melting temperature is 221-229 degree Celsius.
The solder of the invention described here-above can be used as a replacement for Pb-containing solder in solder wave and other hand soldering processes in widespread use in the electronic and other industries.
The solder of the invention is advantageous not only from an environmental standpoint but also from the cost and availability standpoint in that the alloy compounds (Sn, Ag, Cu, Ni, P and/or Ce or La) are readily available at lower cost than the Pb-free solders including large amount of Bi, In, Zn, or Ga proposed to-date. Large volume solder applications especially will benefit from the low cost, high performance solder of the invention having the aforementioned advantages not possesses heretofore by other Pb-free solders.
The above brief description sets forth rather broadly the more important features of the present invention in order that the detailed description thereof that follows may be better understood, and in order that the present contributions to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and will form the subject matter of the claims appended hereto.
In this respect, before explaining the preferred embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangements of the components set forth in the following description. The invention is capable of other embodiments and of being practiced and camed out in various ways. Also, it is to be understood, that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for designing other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing Abstract is to enable the Intellectual Property Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms of phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. Accordingly, the Abstract is neither intended to defme the invention or the application, which only is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
It is therefore an object of the present invention to provide a new and improved composition of an environmental friendly Pb-free solder alloy, which has all of the advantages of the prior art and yet keep our environment green.
It is another object of the present invention to provide a new and improved composition of an environmental friendly Pb-free solder alloy, which may be efficiently manufactured and marketed.
An even further object of the present invention is to provide a new and improved composition of an environmental friendly Pb-free solder alloy, which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such composition available to the buying public.
Still yet a further object of the present invention is to provide a new and improved composition of an environmental friendly Pb-free solder alloy, which can be used to make Pb-free solder bar, wire, paste, BGA ball and anode in electronics industries.
These together with still other objects of the invention, along with the various features of novelty, which characterize the invention, are pointed out with particularity in the claims forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the following detailed description of the preferred embodiments of the invention.
Description of the preferred Embodiment The Pb-free solder of the present invention is based on a composition essentially of about 0.3-0.4 weight % Ag, 0.6-0.7 weight % Cu, 0.01-1.0 weight % Ni, 0.01-0.3 weight % P, 0.001-0.3 weight % Ce or La, and balance weight % Sn, with the additional of Ce or La, not exceeding 0.3 weight % of the overall composition, to enhance better micro-structural stability and to reduce grain size of the resultant solder joints. With the presence of Ni, the thermal stability of the alloy is improved. Further, addition of Ni causes fine crystal texture (forming the Ni-Sn inter-metallic compound), thereby improving strength and thermal fatigue characteristic. Still further, when soldering onto a Cu substrate, addition of Ni suppresses formation of an inter-metallic compound (Cu3Sn), of which Cu-Sn would degrade the soldering strength.
Preferably, for electronic solder applications using the solder wave process, the melting temperature range of the solder should not exceed 10 degree Celsius. This present invention has a solder melting range of 10 degree Celsius.
A preferred Pb-free solders of the invention are listed below, exhibiting off-eutectic melting temperatures:
(1). A electrical conductor Pb-free solder composition consisting essentially of 0.3 %
weight % Ag, 0.7 weight % Cu, 0.3 weight % Ni, 0.05 weight % P, 0.05 weight %
Ce or La, balance Sn and unavoidable impurities, based on the weight of composition. The melting temperature of the solder is in the range of 223 to degree Celsius.
(2). A electrical conductor Pb-free solder composition consisting essentially of 0.4 %
weight % Ag, 0.6 weight % Cu, 0.3 weight % Ni, 0.05 weight % P, 0.05 weight %
Ce or La, balance Sn and unavoidable impurities, based on the weight of composition. The melting temperature of the solder is in the range of 221 to degree Celsius.
The Pb-free solder of the present invention includes at least one non-metallic component consisting essentially of P, in an amount not exceeding 0.3 weight %.
The Pb-free solder of the present invention, which comprises Sn/(0.3-0.4)Ag/(0.6-0.7)Cu/(0.05-0.5)Ni/(not exceeding 0.1)P/(0.001-0.1)Ce or La, is similar as the conventional Pb-free solder comprising Sn/3.OAg/0.5Cu in welding performance, conductivity, mechanical property, pliability and so on. But since the content of Ag of the Pb-free solder of the present invention is about one-tenth of other Pb-free solder comprising Sn/3.OAg/0.5Cu (Ag is trend to react with chemical agents, such as acid or alkali and so on, thereby to produce noxious substance), so the Pb-free solder of the present invention is more safe, and has no adverse effect to living beings and environments in potential. In addition, the content of Ag [less than 0.5%] of the Pb-free solder of the present invention, which comprises Sn/(0.3-0.4)Ag/(0.6-0.7)Cu/(0.01-l.0)Ni/(not exceeding 0.3)P/(0.001-0.3)Ce or La, is less than that of conventional Pb-free SnAgCu solder, so the silver compounds which are generated in the reaction between silver and halogen component of the soldering flux, are not easy to form, as a result, the phenomenon of changing to black is slight.
The method for preparing 500 Kg of the Pb-free solder of the present invention is shown below:
1. 3.5 Kg of pure Cu, 1.5 Kg of pure Ni, 250 g Ce or La and 200 Kg of pure Sn are added into a steel kettle, then heated to the temperature of 400 degree Celsius, and stirred for about 45 minutes;
2. The resulting mixture is cooled to the temperature of 300 degree Celsius, then 293 Kg pure Sn is added into the steel kettle and stirred for about 45 minutes;
In response to the possibility of a governmental ban or excessive taxation of Pb use, manufacturers and users of Pb-bearing solder for electronic and circuit joining applications recently have attempted to developed Pb-free solders as direct replacements for the conventional Sn-Pb solders in conventional hand/wave/reflow soldering processes employing general heating of an electronic wiring board to temperatures of 240-degree Celsius. Moreover, there is a need for such a solder that would be competitive in cost and as readily available as conventional Sn-Pb eutectic solders for high volume use.
A ternary, off-eutectic Sn-Ag-Cu solder alloy has been developed by the plumbing industry as a Pb-free solder with 96 weight % Sn, 3.5 weight % Cu, and 0.5 weight % Ag. This plumbing solder has a 227 degree Celsius of solidus temperature and 260 degree Celsius liquidus temperature, which would be considered not suitable for electronics manufacturers.
Recent developments of Pb-free solder alloys mainly involve the use of Ag, Bi, Cu, In, Sn, and Zn. Special attentions have been drawn on the solder composition comprising Sn, Ag, and Cu. Anderson et. al. of Iowa State University Research have reported the eutectic Pb-free solder comprising 93.6Sn/4.7Ag/1.7Cu and Sn/Ag/Cu/Ni/Fe, respectively.
Summary of the Invention This present invention provides a Pb-free solder comprising a compositions consisting essentially of Sn, Ag, Cu, Ni, P, and/or Ce or La, having a melting temperature of 221-233 degree Celsius.
In one embodiment of the invention, the Pb-free solder consists essentially of 0.3 weight % Ag, 0.7 weight % Cu, 0.3 weight % Ni, 0.05 weight % P, 0.05 weight % Ce or La, and balance of weight % Sn. To the Sn/0.3Ag/0.7Cu/0.3Ni/0.05P, 0.05 weight % of Ce or La is added to improve better micro-structural stability and hence reduce grain size of Sn in the solder composition, and the melting temperature is 223-230 degree Celsius.
In another embodiment of the invention, the Pb-free solder consists essentially of 0.4 weight % Ag, 0.6 weight % Cu, 0.3 weight % Ni, 0.05 weight % P, 0.05 weight %
Ce or La, and balance of weight % Sn. To the Sn/0.4Ag/0.6Cu/0.3Ni/0.05P, 0.05 weight % Ce or La is added to improve better micro-structural stability and hence reduce grain size of Sn in the solder composition, and the melting temperature is 221-229 degree Celsius.
The solder of the invention described here-above can be used as a replacement for Pb-containing solder in solder wave and other hand soldering processes in widespread use in the electronic and other industries.
The solder of the invention is advantageous not only from an environmental standpoint but also from the cost and availability standpoint in that the alloy compounds (Sn, Ag, Cu, Ni, P and/or Ce or La) are readily available at lower cost than the Pb-free solders including large amount of Bi, In, Zn, or Ga proposed to-date. Large volume solder applications especially will benefit from the low cost, high performance solder of the invention having the aforementioned advantages not possesses heretofore by other Pb-free solders.
The above brief description sets forth rather broadly the more important features of the present invention in order that the detailed description thereof that follows may be better understood, and in order that the present contributions to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and will form the subject matter of the claims appended hereto.
In this respect, before explaining the preferred embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangements of the components set forth in the following description. The invention is capable of other embodiments and of being practiced and camed out in various ways. Also, it is to be understood, that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for designing other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing Abstract is to enable the Intellectual Property Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms of phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. Accordingly, the Abstract is neither intended to defme the invention or the application, which only is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
It is therefore an object of the present invention to provide a new and improved composition of an environmental friendly Pb-free solder alloy, which has all of the advantages of the prior art and yet keep our environment green.
It is another object of the present invention to provide a new and improved composition of an environmental friendly Pb-free solder alloy, which may be efficiently manufactured and marketed.
An even further object of the present invention is to provide a new and improved composition of an environmental friendly Pb-free solder alloy, which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such composition available to the buying public.
Still yet a further object of the present invention is to provide a new and improved composition of an environmental friendly Pb-free solder alloy, which can be used to make Pb-free solder bar, wire, paste, BGA ball and anode in electronics industries.
These together with still other objects of the invention, along with the various features of novelty, which characterize the invention, are pointed out with particularity in the claims forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the following detailed description of the preferred embodiments of the invention.
Description of the preferred Embodiment The Pb-free solder of the present invention is based on a composition essentially of about 0.3-0.4 weight % Ag, 0.6-0.7 weight % Cu, 0.01-1.0 weight % Ni, 0.01-0.3 weight % P, 0.001-0.3 weight % Ce or La, and balance weight % Sn, with the additional of Ce or La, not exceeding 0.3 weight % of the overall composition, to enhance better micro-structural stability and to reduce grain size of the resultant solder joints. With the presence of Ni, the thermal stability of the alloy is improved. Further, addition of Ni causes fine crystal texture (forming the Ni-Sn inter-metallic compound), thereby improving strength and thermal fatigue characteristic. Still further, when soldering onto a Cu substrate, addition of Ni suppresses formation of an inter-metallic compound (Cu3Sn), of which Cu-Sn would degrade the soldering strength.
Preferably, for electronic solder applications using the solder wave process, the melting temperature range of the solder should not exceed 10 degree Celsius. This present invention has a solder melting range of 10 degree Celsius.
A preferred Pb-free solders of the invention are listed below, exhibiting off-eutectic melting temperatures:
(1). A electrical conductor Pb-free solder composition consisting essentially of 0.3 %
weight % Ag, 0.7 weight % Cu, 0.3 weight % Ni, 0.05 weight % P, 0.05 weight %
Ce or La, balance Sn and unavoidable impurities, based on the weight of composition. The melting temperature of the solder is in the range of 223 to degree Celsius.
(2). A electrical conductor Pb-free solder composition consisting essentially of 0.4 %
weight % Ag, 0.6 weight % Cu, 0.3 weight % Ni, 0.05 weight % P, 0.05 weight %
Ce or La, balance Sn and unavoidable impurities, based on the weight of composition. The melting temperature of the solder is in the range of 221 to degree Celsius.
The Pb-free solder of the present invention includes at least one non-metallic component consisting essentially of P, in an amount not exceeding 0.3 weight %.
The Pb-free solder of the present invention, which comprises Sn/(0.3-0.4)Ag/(0.6-0.7)Cu/(0.05-0.5)Ni/(not exceeding 0.1)P/(0.001-0.1)Ce or La, is similar as the conventional Pb-free solder comprising Sn/3.OAg/0.5Cu in welding performance, conductivity, mechanical property, pliability and so on. But since the content of Ag of the Pb-free solder of the present invention is about one-tenth of other Pb-free solder comprising Sn/3.OAg/0.5Cu (Ag is trend to react with chemical agents, such as acid or alkali and so on, thereby to produce noxious substance), so the Pb-free solder of the present invention is more safe, and has no adverse effect to living beings and environments in potential. In addition, the content of Ag [less than 0.5%] of the Pb-free solder of the present invention, which comprises Sn/(0.3-0.4)Ag/(0.6-0.7)Cu/(0.01-l.0)Ni/(not exceeding 0.3)P/(0.001-0.3)Ce or La, is less than that of conventional Pb-free SnAgCu solder, so the silver compounds which are generated in the reaction between silver and halogen component of the soldering flux, are not easy to form, as a result, the phenomenon of changing to black is slight.
The method for preparing 500 Kg of the Pb-free solder of the present invention is shown below:
1. 3.5 Kg of pure Cu, 1.5 Kg of pure Ni, 250 g Ce or La and 200 Kg of pure Sn are added into a steel kettle, then heated to the temperature of 400 degree Celsius, and stirred for about 45 minutes;
2. The resulting mixture is cooled to the temperature of 300 degree Celsius, then 293 Kg pure Sn is added into the steel kettle and stirred for about 45 minutes;
3. 1.5 Kg of pure silver is added into the steel kettle, then heated to the temperature of 370 degree Celsius, and stirred for about 45 minutes;
4. 250 g P is pulverized and added into the steel kettle and stirred for about minutes at the temperature of 370 degree Celsius.
The solder of the present invention can be provided in many forms as needed for particular solder applications. The solder of the present invention can be provided as solder wire, solder bar, solder ingot, and solder powder. The solder bar and ingot can be manufactured by convention solder smelting technique. The smelting solder should be stirred 360 30 degree Celsius for 45 minutes, then let drop to 300 degree Celsius. The solder the can be chilled cast, from 300 degree Celsius to 65 10 degree Celsius, into suitable steel molds to produce bars or ingots having high purity and compositional accuracy. The solder wire can be extruded from ingot into hollow wire, which is then filled with core flux.
The above brief description sets forth rather broadly the more important features of the present invention in order that the detailed description thereof that follows may be better understood, and in order that the present contributions to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and will form the subject matter of the claims appended hereto.
In this respect, before explaining the preferred examples of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangements of the components set forth in the following description. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood, that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
It is an object of the present invention to provide a Sn-Ag-Cu Pb-free solder alloy, addition of Ni (0.01-1.0 weight %), trace amount of P(0.01-0.3 weight %) and trace amount of rare earth (Ce or La in the range 0.001-0.3 weight %), can improve thermal stability, better micro-structural stability and reduce joint oxidation rate, hence, reduce the formation of course grain solder joint. Furthermore, the surface of soldering tin is not trend to change black, so the amount of metal oxide produced in the steel kettle of solder can be reduced, and the defective fraction rate can be reduced during electro wiring board soldering.
Example 1 The Pb-free solder of this example consists of the following components, based on the weight %: 0.3 weight % Ag, 0.7 weight % Cu, 0.3 weight % Ni, 0.05 weight %
Ce or La, 0.05 weight % P, and balance Sn.
Example 2 The Pb-free solder of this example consists of the following components, based on the weight %: 0.4 weight % Ag, 0.6 weight % Cu, 0.3 weight % Ni, 0.05 weight %
Ce or La, 0.05 weight % P, and balance Sn.
The raw materials, weights thereof, processing steps and processing conditions for preparing the Pb-free solder have been described in detail in foregoing paragraphs. Now, the example 1 and 2 are listed in table 1. [see table 1]
The solder of the present invention can be provided in many forms as needed for particular solder applications. The solder of the present invention can be provided as solder wire, solder bar, solder ingot, and solder powder. The solder bar and ingot can be manufactured by convention solder smelting technique. The smelting solder should be stirred 360 30 degree Celsius for 45 minutes, then let drop to 300 degree Celsius. The solder the can be chilled cast, from 300 degree Celsius to 65 10 degree Celsius, into suitable steel molds to produce bars or ingots having high purity and compositional accuracy. The solder wire can be extruded from ingot into hollow wire, which is then filled with core flux.
The above brief description sets forth rather broadly the more important features of the present invention in order that the detailed description thereof that follows may be better understood, and in order that the present contributions to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and will form the subject matter of the claims appended hereto.
In this respect, before explaining the preferred examples of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangements of the components set forth in the following description. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood, that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
It is an object of the present invention to provide a Sn-Ag-Cu Pb-free solder alloy, addition of Ni (0.01-1.0 weight %), trace amount of P(0.01-0.3 weight %) and trace amount of rare earth (Ce or La in the range 0.001-0.3 weight %), can improve thermal stability, better micro-structural stability and reduce joint oxidation rate, hence, reduce the formation of course grain solder joint. Furthermore, the surface of soldering tin is not trend to change black, so the amount of metal oxide produced in the steel kettle of solder can be reduced, and the defective fraction rate can be reduced during electro wiring board soldering.
Example 1 The Pb-free solder of this example consists of the following components, based on the weight %: 0.3 weight % Ag, 0.7 weight % Cu, 0.3 weight % Ni, 0.05 weight %
Ce or La, 0.05 weight % P, and balance Sn.
Example 2 The Pb-free solder of this example consists of the following components, based on the weight %: 0.4 weight % Ag, 0.6 weight % Cu, 0.3 weight % Ni, 0.05 weight %
Ce or La, 0.05 weight % P, and balance Sn.
The raw materials, weights thereof, processing steps and processing conditions for preparing the Pb-free solder have been described in detail in foregoing paragraphs. Now, the example 1 and 2 are listed in table 1. [see table 1]
Claims (16)
1. A Pb-free electrical conductor solder composition consisting essentially of about 0.3-0.4 weight % Ag, 0.6-0.7 weight % Cu, 0.01-1.0 weight % Ni, optionally 0.001-0.3 weight % Ce, and not more than 0.3 weight % P, balance Sn and unavoidable impurities, based on the weight of composition.
2. A Pb-free electrical conductor solder composition consisting essentially of about 0.3-0.4 weight % Ag, 0.6-0.7 weight % Cu, 0.01-1.0 weight % Ni, optionally 0.001-0.3 weight % La, and not more than 0.3 weight % P, balance Sn and unavoidable impurities, based on the weight of composition.
3. The Pb-free electrical conductor solder composition of claim 1 consisting essentially of 0.3 weight % Ag, 0.7 weight % Cu, 0.01-1.0 weight % Ni, optionally 0.001-0.3 weight % Ce, and 0.01 to 0.3 weight % P, balance Sn and unavoidable impurities, based on the weight of composition.
4. The Pb-free electrical conductor solder composition of claim 2 consisting essentially of 0.3 weight % Ag, 0.7 weight % Cu, 0.01-1.0 weight % Ni, optionally 0.001-0.3 weight % La, and 0.01 to 0.3 weight % P, balance Sn and unavoidable impurities, based on the weight of composition.
5. The Pb-free electrical conductor solder composition of claim 1 consisting essentially of 0.4 weight % Ag, 0.6 weight % Cu, 0.01-1.0 weight % Ni, optionally 0.001-0.3 weight % Ce, and 0.01 to 0.3 weight % P, balance Sn and unavoidable impurities, based on the weight of composition.
6. The Pb-free electrical conductor solder composition of claim 2 consisting essentially of 0.4 weight % Ag, 0.6 weight % Cu, 0.01-1.0 weight % Ni, optionally 0.001-0.3 weight % La, and 0.01 to 0.3 weight % P, balance Sn and unavoidable impurities, based on the weight of composition.
7. The Pb-free electrical conductor solder composition of any one of claims 1, 3, and 5, wherein the content of Ce is less than 0.1 weight %.
8. The Pb-free electrical conductor solder composition of any one of claims 1, 3, and 5, wherein the content of Ce is 0.05 weight %.
9. The Pb-free electrical conductor solder composition of any one of claims 2, 4, and 6, wherein the content of La is less than 0.1 weight %.
10. The Pb-free electrical conductor solder composition of any one of claims 2, 4, and 6, wherein the content of La is 0.05 weight %.
11. The Pb-free electrical conductor solder composition of any one of claims 1 to 2, wherein the content of La is in the range of 0.001 to 0.1 weight %.
12. The Pb-free electrical conductor solder composition of any one of claims 1 to 2, wherein the content of Ni is less than 0.8 weight %.
13. The Pb-free electrical conductor solder composition of any one of claims 1 to 2, wherein the content of Ni is less than 0.5 weight %.
14. The Pb-free electrical conductor solder composition of any one of claims 1 to 2, wherein the content of Ni is less than 0.1 weight %.
15. The Pb-free electrical conductor solder composition of any one of claims 1 to 2, wherein the content of P is less than 0.1 weight %.
16. The Pb-free electrical conductor solder composition of any one of claims 1 to 2, wherein the content of P is 0.05 weight %.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2540486 CA2540486A1 (en) | 2006-03-20 | 2006-03-20 | Pb-free solder alloy compositions comprising essentially tin (sn), silver (ag), copper (cu), nickel (ni), phosphorus (p) and/or rare earth: cerium (ce) or lanthanum (la) |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2540486 CA2540486A1 (en) | 2006-03-20 | 2006-03-20 | Pb-free solder alloy compositions comprising essentially tin (sn), silver (ag), copper (cu), nickel (ni), phosphorus (p) and/or rare earth: cerium (ce) or lanthanum (la) |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2540486A1 true CA2540486A1 (en) | 2007-09-20 |
Family
ID=38520907
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2540486 Abandoned CA2540486A1 (en) | 2006-03-20 | 2006-03-20 | Pb-free solder alloy compositions comprising essentially tin (sn), silver (ag), copper (cu), nickel (ni), phosphorus (p) and/or rare earth: cerium (ce) or lanthanum (la) |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2540486A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102581516A (en) * | 2012-03-27 | 2012-07-18 | 郑州机械研究所 | Super-plastic copper and phosphorous welding rod and preparation method thereof |
| CN106607650A (en) * | 2015-10-23 | 2017-05-03 | 东莞市天铖锡业有限公司 | Rare earth cerium solder alloy soldering paste |
| CN112222680A (en) * | 2020-09-14 | 2021-01-15 | 中国航发北京航空材料研究院 | A method for designing multi-component solder components based on valence bond theory |
| CN112222681A (en) * | 2020-09-14 | 2021-01-15 | 中国航发北京航空材料研究院 | Method for designing Ti-Zr-based brazing filler metal components based on thermodynamic factors and unit cell structural factors |
| CN113843546A (en) * | 2021-09-23 | 2021-12-28 | 金华市金钟焊接材料有限公司 | CuPSnAg Ni-Re ultra-silver solder, preparation method and application |
-
2006
- 2006-03-20 CA CA 2540486 patent/CA2540486A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102581516A (en) * | 2012-03-27 | 2012-07-18 | 郑州机械研究所 | Super-plastic copper and phosphorous welding rod and preparation method thereof |
| CN106607650A (en) * | 2015-10-23 | 2017-05-03 | 东莞市天铖锡业有限公司 | Rare earth cerium solder alloy soldering paste |
| CN112222680A (en) * | 2020-09-14 | 2021-01-15 | 中国航发北京航空材料研究院 | A method for designing multi-component solder components based on valence bond theory |
| CN112222681A (en) * | 2020-09-14 | 2021-01-15 | 中国航发北京航空材料研究院 | Method for designing Ti-Zr-based brazing filler metal components based on thermodynamic factors and unit cell structural factors |
| CN113843546A (en) * | 2021-09-23 | 2021-12-28 | 金华市金钟焊接材料有限公司 | CuPSnAg Ni-Re ultra-silver solder, preparation method and application |
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