Characteristics of press-soldered joints by using resistance heating

In order to increase the strengths of soldered joints, a novel press-soldering method was investigated. In this method, materials of low melting points and low strengths (mainly Pb) were discharged from the joint interface and an alloyed layer of high strength was left. Copper-to-copper lap joints were press-soldered using a resistance heating apparatus. In this process, heating and pressure were applied simultaneously. The copper plate was presoldered using Pb-50 Sn solder, and the alloyed layer was formed. The tensile strengths increased at a pressure above 45 N, and fracturing occurred in the copper base metal above a 75-N pressure load. The joints fractured in the copper base metal during the 150 degrees C and 250 degrees C tensile testing and showed excellent thermal resistance. Changes in joint strengths after high-temperature heating (150 degrees C, 250 degrees C, 1000 h) are also considered.<
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