Phase formation in the diffusion couple of aluminum thin film and gold bulk and the influence of calcium on the phase formation

Masaki Hanai, Masafumi Houkyou, Naoki Utiyama, Akio Fuwa

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    The behavior of phase layer growth in the diffusion couple of aluminum thin films and gold bulks at the temperatures from 523 K to 773 K was studied by means of SEM, EPMA and optical microscopy. The effect of calcium addition on phase layer growth was also studied. The experimental results show: before the disappearance of aluminum thin films, five intermetallic phases in its equilibrium phase diagram form in the couple and after the aluminum disappearance, the phases with a lesser gold content disappear in sequences. After the disappearance of the AuAl2, AuAl and Au2Al phases, the Au4Al phase grows in the Au5Al2. Kirkendall voids are found to form in the Au5Al2, adjacent to Au4Al. The addition of a small amount of calcium to the Au bulks affects the morpohology, making void sizes smaller and diffusion easier, thus promoting the growth of the Au4Al phase.

    Original languageEnglish
    Pages (from-to)37-43
    Number of pages7
    JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
    Issue number1
    Publication statusPublished - 1996



    • Aluminum thin film
    • Calcium addition
    • Diffusion couple
    • Gold bulk
    • Kirkendall void
    • Phase formation

    ASJC Scopus subject areas

    • Metals and Alloys

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