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US 5,690,890 AGranted
Solder
AssigneesMatsushita Electric Industrial Co., Ltd., Kabushiki Kaisha Nihon Genma
InventorsYasuji Kawashima, Takashi Nagashima, Akihiko Matsuike, Takeshi Meguro, Kaoru Shimizu, Hideo Chaki, Toshiaki Ogura
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Abstract
A tin-lead alloy solder is provided which exhibits high joint strength under conditions which are likely to induce fatigue fracture. The tin-lead alloy solder comprises 15-80 wt. % lead, 0.1-5 wt. % silver, 0.1-10 wt. % antimony, and 0.0005-0.3 phosphorus, the balance being tin.
Claims1
A tin-lead alloy solder having improved thermal fatigue characteristics which consists of
- 15-80 wt. % lead,
- 0.1-5 wt. % silver,
- 0.1-10 wt. % antimony,
- 0.0005-0.3 wt. % phosphorus, and
- the balance being essentially tin,
- wherein a portion up to 70% of lead is replaced with at least one metal selected from the group consisting of cadmium, zinc and gallium, wherein cadmium is present in an amount of 5-22 wt. %, zinc is present in an amount up to 22 wt. %, and gallium is present in an amount of 0.001 to 1 wt. %, all weight percentages of the replacement metal being based upon the total weight of the solder, and
- wherein a portion of the antimony, up to 70% thereof, is replaced with at least one metal selected from the group consisting of aluminum, gold, magnesium, cerium, platinum, palladium, cobalt, germanium, chromium, manganese, zirconium, nickel and tellurium, each present in an amount of from 0.001 to 1 wt. %, which proportions of said metal are based upon the total weight of the solder.
4 more elements
Dependencies are inferred from the claim text.