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Solder Paste – Alloys

Category:
  • Solder Alloys
  • Indium Corporation
  • Solar
  • Solder Paste
  • SAC Solder
  • Solder
  • Soldering
  • Solderability

  • Much to the surprise of the SnPb and SAC alloy consuming world, there are a number of alloys available in solder paste, each with their own unique melting points and soldering and mechanical properties. Below is a table containing some of the alloys possible in solder paste (not exhaustive).

     

    Alloy Composition

    Melting Temperature (Solidus/Liquidus)

    46Bi 34Sn 20Pb

    96C (Eutectic)

    52In 48Sn

    118C (Eutectic)

    58Bi 42Sn

    138C (Eutectic)

    57Bi 42Sn 1Ag

    139C/140C

    97In 3 Ag

    143C (Eutectic)

    80In 15Pb 5Ag

    149C/154C

    100In

    157 (Melting Point)

    43Pb 43Sn 14Bi

    144C/163C

    70In 30Pb

    165C/175C

    62Sn 36Pb 2Ag

    179C

    60In 40Pb

    173C/181C

    63Sn 37Pb

    183C (Eutectic)

    50In 50Pb

    184C/210C

    Sn Ag Cu (SAC alloys)

    217C/220C

    96.5Sn 3.5Ag

    221C (Eutectic)

    95Sn 5Sb

    235C/240C

    80Au 20Sn

    280C (Eutectic)

    88Pb 10Sn 2Ag

    267C/299C

    92.5Pb 5Sn 2.5Ag

    287C/296C

    92.5Pb 5In 2.5Ag

    300C/310C

    95Pb 5Sn

    308C/312C

     

    None of these individual metals are found pure on the planet. They have to be mined, refined and then alloyed to the proper proportion with the other metals to create these solder alloys. Oftentimes a wet chemical technique is required after alloying to validate that the alloy meets the allowable tolerances and purities spelled out in J-STD-006 or a customer specific specification.