Fabrication of Al2O3-W functionally graded materials by slipcasting method

Tomoyuki Katayama, Sohei Sukenaga, Noritaka Saito, Hajime Kagata, Kunihiko Nakashima

    研究成果: ジャーナルへの寄稿会議記事査読

    7 被引用数 (Scopus)


    We have successfully fabricated a functionally graded material (FGM) from tungsten and alumina powders by a slip-casting method. This FGM has applications as a sealing and conducting component for high-intensity discharge lamps (HiDLs) that have a translucent alumina envelope. Two types of W powder, with different oxidizing properties, were used as the raw powders for the Al2O3-W FGM. "Oxidized W" was prepared by heat-treatment at 200 °C for 180 min in air. Alumina and each of the W powders were mixed in ultrapure water by ultrasonic stirring. The slurry was then cast into a cylindrical acrylic mold, which had a base of porous alumina, under controlled pressure. The green compacts were subsequently dried, and then sintered using a vacuum furnace at 1600 °C for a fixed time. The microstructures of the FGMs were observed by scanning electron microscopy (SEM) of the polished section. The Al2O3-W FGM with the "oxidized W" powder resulted in a microscopic compositional gradient. However, the FGM with "as-received W" showed no compositional gradient. This result was mainly attributed to the difference between the ζ-potentials of the W powders with the different oxidizing conditions; basically "oxidized W" powder tends to disperse because of the larger ζ-potential of the oxide layer coated on the W powder core.

    ジャーナルIOP Conference Series: Materials Science and Engineering
    出版ステータス出版済み - 2011
    イベント3rd International Congress on Ceramics, ICC 2011 - Osaka, 日本
    継続期間: 11月 14 201011月 18 2010

    !!!All Science Journal Classification (ASJC) codes

    • 材料科学(全般)
    • 工学(全般)


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