| 摘要 |
A solder paste compsn. contains (a) 4-96 wt.% eutectic metal alloy, (b) 96-4 wt.% metal additive and (c) an organic medium. The eutectic may be a pseudo-eutectic metal alloy which may be used as a mixt. with a eutectic alloy. Both the eutectic additive are in the form of finely divided particles. The additive may be a pure metal, mixts. or alloys thereof and has a m.pt. at least 30 deg.C greater than the m.pt. of the eutectic. A paste contg. 10-50, pref. 20-30, wt.% of (a) and 90-50, pref. 80-70, wt.% of (b). The eutectic contains 63% Sn and 37% Pb or 62% Sn, 36% Pb and 2% Ag. The metal additive is a Sn-Pb-Ag lead-silver alloy contg. at least 40 wt.% Pb. The metal additive is an alloy contg. at least 70 wt.% Pb, pref. at least 88 wt.% Pb. Examples include 10Sn/90Pb, 10Sn/88Pb/2Ag, 5Sn/95Pb and 3Sn/97Pb. |
