Fabrication of fine α-alumina powders by thermal decomposition of ammonium aluminum carbonate hydroxide (AACH)

K. Morinaga, T. Torikai, K. Nakagawa, S. Fujino

    Research output: Contribution to journalArticle

    74 Citations (Scopus)

    Abstract

    In this paper, the phase transformations that occur during the thermal decomposition of ammonium aluminum carbonate hydroxide (AACH) into α-Al2O3 have been studied. Amorphous, γ-, and θ-Al2O3 were identified as intermediate products. A time-temperature-transformation (TTT) diagram for thermal decomposition in air was determined. The critical particle size of θ-Al2O3 in the θ→α phase transformation is approximately 30 nm; the size does not depend on the firing atmosphere. However, the atmosphere affects the grain size distribution of the final α-Al2O3 particles. Powders with an average grain size of 60 nm were obtained by firing in vacuum or hydrogen.

    Original languageEnglish
    Pages (from-to)4735-4741
    Number of pages7
    JournalActa Materialia
    Volume48
    Issue number18-19
    DOIs
    Publication statusPublished - Dec 1 2000

    All Science Journal Classification (ASJC) codes

    • Electronic, Optical and Magnetic Materials
    • Ceramics and Composites
    • Polymers and Plastics
    • Metals and Alloys

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