Other

Matsushita Electric Industrial Co., Ltd.

Senju Metal Industry Co., Ltd.

Hiroji Noguchi

Toshihiko Taguchi

Masahiko Hirata

Takashi Hori

Shozo Asano

Toshikazu Murata

Ryo Oishi

Sadao Kishida

Takao Hisazumi

Hisahiko Yoshida

Tetsuhiko Isobe

Mamoru Senna

Kunihito Takaura

Takashi Ohashi

A lead-free solder alloy having a relatively low melting temperature and suitable for use to solder electronic devices consists essentially of: from 7 to 10 wt % of Zn; at least one of from 0.01 to 1 wt % of Ni, from 0.1 to 3.5 wt % of Ag, and from 0.1 to 3 wt % of Cu; optionally at least one of from 0.2 to 6 wt % of Bi, from 0.5 to 3 wt % of In, and from 0.001 to 1 wt % of P; and a balance of Sn. Another such lead-free solder alloy consists essentially of: from 2 to 10 wt % of Zn; from 10 to 30 wt % of Bi; from 0.05 to 2 wt % of Ag; optionally from 0.001 to 1 wt % of P, and a balance of Sn. These solder alloys have a tensile strength of at least 5 kgf/mm and at least 10% elongation.

Lead-free solder alloys

An organic acid salt is deposited on the surface of a solder powder containing Sn and Zn. Alternatively, 0.5 to 10 wt. % of a nonionic surfactant is added to a flux. By a method comprising such a procedure, provided are a lead-free solder powder and solder paste having good soldering characteristics wherein the reaction of an activating component with an alloy component in a flux is suppressed.

Solder powder and method for preparing the same and solder paste

A lead-free solder alloy having a relatively low melting temperature and suitable for use to solder electronic devices consists essentially of: from 7 to 10 wt % of Zn; at least one of from 0.01 to 1 wt % of Ni, from 0.1 to 3.5 wt % of Ag, and from 0.1 to 3 wt % of Cu; optionally at least one of from 0.2 to 6 wt % of Bi, from 0.5 to 3 wt % of In, and from 0.001 to 1 wt % of P; and a balance of Sn. Another such lead-free solder alloy consists essentially of: from 2 to 10 wt % of Zn; from 10 to 30 wt % of Bi; from 0.05 to 2 wt % of Ag; optionally from 0.001 to 1 wt % of P, and a balance of Sn. These solder alloys have a tensile strength of at least 5 kgf/mm,and at least 10% elongation.

In order to prevent aging of an Sn--Zn system alloy solder paste, 0.5-5% by weight of a compound obtained by adding an ethylene oxide to cyclohexylamine, preferably together with 0.5-5% by weight of a polyoxyethylene alkylamine is added to a flux of said solder paste.

Solder paste

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Kadoma, Japan

Hiroji Noguchi