US2004141873A1PendingUtilityA1

Solder composition substantially free of lead

42
Priority: Jan 22, 2003Filed: Feb 27, 2003Published: Jul 22, 2004
Est. expiryJan 22, 2023(expired)· nominal 20-yr term from priority
Inventors:Tadashi TakemotoTakashi NagaseTakashi UetaniMorio Yamazaki
C22C 13/02B23K 35/262B23K 2101/38B23K 35/362B23K 35/0227
42
PatentIndex Score
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Cited by
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References
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Claims

Abstract

This invention provides solder that is substantially free of lead that minimizes corrosion from occurring in the soldering equipment such as the tip of the soldering iron and soldering dipping tank. Without substantial, if any, amount of lead in the solder, the solder does not expose lead into the environment. The solder composition also includes element(s) that extend the life of the soldering tip or other equipments associated with soldering. The solder composition may include Sn (tin) along with Co (cobalt) and Fe (iron). Tin may make up the most of the content in the solder composition. The two elements cobalt and iron substantially inhibit tin from corroding the iron, thereby substantially preventing the soldering iron tip and dipping solder tank from corroding. The composition of the solder may also include Ag (silver) to improve the mechanical strength and wettability of the solder. Alternatively, the composition may include Ni (nickel) to improve the wettability of the solder as well, along with other elements.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
         1 . A solder composition having substantial content of tin by mass, the solder composition further comprising: 
 between about 0.2% and about 5% of silver by mass of the solder composition; and    between about 0.01% and about 1.0% of iron by mass of the solder composition.    
     
     
         2 . The solder composition according to  claim 1 , further including: 
 between about 0.1% and about 5.0% of bismuth by mass of the solder composition.    
     
     
         3 . The solder composition according to  claim 1 , further including: 
 between about 0.1% and about 2.50% of cobalt by mass of the solder composition.    
     
     
         4 . The solder composition according to  claim 1 , further including: 
 flux to formulate the solder composition into a wire.    
     
     
         5 . A solder composition having substantial content of tin by mass, the solder composition further comprising: 
 between about 0.2% and about 5% of silver by mass of the solder composition; and    between about 0.01% and about 1.0% of cobalt by mass of the solder composition.    
     
     
         6 . A solder composition having substantial content of tin by mass, the solder composition further comprising: 
 between about 0.2% and about 5% of silver by mass of the solder composition; and    between about 0.01% and about 1.0% of nickel by mass of the solder composition.    
     
     
         7 . A solder composition having substantial content of tin by mass, the solder composition further comprising: 
 between about 0.2% and about 5% of silver by mass of the solder composition;    between about 0.01% and about 1.0% of iron by mass of the solder composition;    between about 0.01% and about 1.0% of cobalt by mass of the solder composition; and    between about 0.01% and about 1.0% of nickel by mass of the solder composition, where the combined mass of the iron, cobalt, and nickel is less than about 1.0% of the solder composition.    
     
     
         8 . A solder composition having substantial content of tin by mass, the solder composition further comprising: 
 between about 0.2% and about 5% of silver by mass of the solder composition;    between about 0.01% and about 1.0% of nickel by mass of the solder composition; and    between about 0.01% and about 1.0% of cobalt by mass of the solder composition, where the combined mass of the nickel and cobalt is less than about 1% of the solder composition.    
     
     
         9 . A process for soldering electrical components comprising: 
 providing a lead-free solder including tin (Sn) as its main component and cobalt (Co), iron (Fe), and nickel (Ni) each in the amount of between about 0.01 to 1 percent by mass, and the combined amount of cobalt, iron and nickel being equal to or smaller than about 1 percent by mass;    heating said lead free solder with a soldering iron to melt said lead free solder; and    applying said melted lead free solder to an electrical component.    
     
     
         10 . The process of  claim 9  wherein said lead free solder further comprises silver (Ag) in the amount of between about 0.2 to 5 percent by mass.  
     
     
         11 . The process of  claim 9  wherein said lead free solder contains copper (Cu) in the amount of between about 0.1 to 2.5 percent by mass.  
     
     
         12 . A lead free solder composition for use in soldering electrical components wherein said lead free solder composition has a corrosive level approximately equal to lead based solder compositions, said lead free solder comprising:  
     
     
         13 . Tin (Sn) as its main component and cobalt (Co), iron (Fe), and nickel (Ni) each in the amount of between about 0.01 to 1 percent by mass, and the combined amount of cobalt, iron and nickel being equal to or smaller than about 1 percent by mass.  
     
     
         14 . The lead free solder of  claim 12  further comprising silver (Ag) in the amount of between about 0.2 to 5 percent by mass.  
     
     
         15 . The lead free solder of  claim 12  further comprising copper (Cu) in the amount of between about 0.1 to 2.5 percent by mass.

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