Patent ID: 8241760
Filing Date: 2012-08-14
Classification: B23K,C25D,H05K,Y02P,Y10T

Abstract:
1. A joint structure, comprising: a conductive member containing copper as a major component thereof; an electrode member containing copper as a major component thereof; and a joint portion through which the conductive member and the electrode member are joined together, the joint portion consisting of a central part integrally formed with both the conductive member and the electrode member and an outer circumference part integrally formed with the central part so as to surround the central part, the outer circumference part being integrally formed with only the central part and the electrode member, wherein both the central part and the outer circumference part of the joint portion are formed of a copper-tin alloy obtained by melting a brazing material containing tin as a major component thereof and containing substantially no copper, and diffusing copper atoms of the copper contained in the conductive member and the electrode member into the brazing material; a concentration of copper atoms in the central part is higher than that in the outer circumference part and is 40 to 80 atom %; and in the case where the concentration of the copper atoms in the central part is defined as S1, and the concentration of the copper atoms in the outer circumference part is defined as S2, a difference between S1 and S2 (S1−S2) is 10 to 30 atom %.