Development of bi-base high-temperature Pb-free solders with second-phase dispersion: Thermodynamic calculation, microstructure, and interfacial reaction

• Published in: Journal of electronic materials Vol. 35; no. 11; pp. 1926 - 1932
• Main Authors: TAEAKU, Yoshikazu, OHNUMA, Ikuq, KAINUMA, Ryosuke, YAMADA, Yasushi, YAGI, Yuji, NISHIBE, Yuji, ISHIDA, Kiyohito
• Format: Conference Proceeding Journal Article
• Language: English
• Published: New York, NY Institute of Electrical and Electronics Engineers 01.11.2006; Springer Nature B.V
• Subjects: Antimony; Applied sciences; Atomizing; Bismuth; Bonding strength; Brazing. Soldering; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronics; Exact sciences and technology; High temperature; Interface reactions; Intermetallic compounds; Joining, thermal cutting: metallurgical aspects; Lead free; Lead free solders; Materials science; Mathematical analysis; Melt spinning; Melting points; Metals. Metallurgy; Microstructure; Miscibility; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Solders; Structure and morphology; thickness; Substrates; Surface and interface electron states; Surface states, band structure, electron density of states; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermodynamics; Thin film structure and morphology; Tin; Interfacial layer; Phase diagram; Miscibility gap; Melt spinning; CALPHAD; fine dispersed particles; High temperature; Precipitate; high-temperature solder; Composite material; Thin film; Actinide; Thermodynamic model; Fine particle; Pb-free solder; Database; Lead free solder; Interface reaction; Band structure; Intermetallic compound; Brittleness; Dispersion; ADAMIS (alloy database for micro-solders); Soldered joint; Microstructure; Melting point; Atomizing
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-006-0295-6

Bismuth and its alloys are candidates for Pb-free high-temperature solders that can be substituted for conventional Pb-rich Pb-Sn solders (melting point (mp) = 573-583 K). However, inferior properties such as brittleness and weak bonding strength should be improved for practical use. To that end, BiCu-X (X = Sb, Sn, and Zn) Pb-free high-temperature solders are proposed. Miscibility gaps in liquid BiCu-X alloys were surveyed using the thermodynamic database ADAMIS (alloy database for micro-solders), and compositions of the BiCu-X solders were designed on the basis of calculation. In-situ composite solders that consist of a Bi-base matrix with fine intermetallic compound (IMC) particles were produced by gas-atomizing and melt-spinning methods. The interfacial reaction between in-situ composite solders and Cu or Ni substrates was investigated. The IMCs at the interface formed a thin, uniform layer, which is an appropriate morphology for a reliable solder joint. [PUBLICATION ABSTRACT]