Susumu Arai1 and Tohru Watanabe2
1Precision Technology Research Institute of Nagano Prefecture, Okaya, Nagano
Sn-Ag alloys, which are considered to be suitable for use as Pb-free solders, were formed by an electrodeposition method. In the alloys formed by an electrodeposition method, un-equilibrium phases, which do not exist in the phase diagram occasionally appear. Therefore the composition, morphology, produced phases and microstructure of the elecrtodeposited Sn-Ag alloys were studied. The results are summarized as follows.
(1) A good relationship was observed between the morphologies of the electrodeposited Sn-Ag alloys and their compositions.
(2) The electrodeposited Sn-Ag alloys had two phases (β-Sn and an intermetallic compound) in the range of 5 to 75 atomic percent Ag content, and were composed of grains of submicron-order diameter.
(3) The phases which exist in the electrodeposited Sn-Ag alloys were those reported in the Sn-Ag alloy phase diagram.
(Received April 26, 1996)
tin-silver alloy, electrodeposition method, morphology, phase, microstructure, phase diagram
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