粉体工学会誌
Online ISSN : 1883-7239
Print ISSN : 0386-6157
ISSN-L : 0386-6157
57 巻 , 12 号
選択された号の論文の6件中1~6を表示しています
論文
  • 田坂 太一, 大村 高弘, 萩原 伸治, 近藤 光, 内藤 牧男
    原稿種別: 論文
    2020 年 57 巻 12 号 p. 612-618
    発行日: 2020/12/10
    公開日: 2021/02/13
    ジャーナル フリー

    In recent years, new thermal insulation materials with lower thermal conductivity and light weight have been developed. However, their practical use is limited only under 1000°C. In this paper, the performances of thermal insulation properties of fibrous fumed alumina compact were evaluated at the temperature up to 1200°C. As a result, it revealed low thermal conductivity in the range of 0.040–0.065 W/(m·K) between 200°C and 1000°C. However, after receiving the temperature history of 1200°C processing, its thermal conductivity increased up to 1.4 times compared to that before heat processing. On the contrary, the compressive strength was not changed by the temperature history. The increase of thermal conductivity by the temperature history was explained by the increase of solid thermal conductivity due to the sintering of particles in the compact.

  • 中村 寿樹, 武藤 則男, 中平 敦
    原稿種別: 論文
    2020 年 57 巻 12 号 p. 619-626
    発行日: 2020/12/10
    公開日: 2021/02/13
    ジャーナル フリー

    In this study, the rapid debinding of zirconia molded bodies was carried out using a superheated steam treatment. The superheated steam treatment was performed with the heating rate of 10°C/min to a holding temperature range of 500°C to 800°C. The molded body after superheated steam treatment to 800°C resulted in the residual carbon content of 0.3%. No cracking occurred in sintered bodies obtained by debinding in the superheated steam and then firing at 1500°C in air, although many large cracks occurred in sintered bodies that had been treated in air or nitrogen under similar temperature conditions. To understand the debinding behavior under the superheated steam, thermal analyses were performed with thermogravimetric. These results suggested that the debinding in superheated steam suppressed thermal runaway and the generation of pyrolysis gas caused by the chain of exothermic reactions derived from the oxidation of the forming aid. Thus, it was suggested that superheated steam treatment is highly effective for rapid debinding of molded bodies.

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  • 田村 崇弘, 石川 剛, 木俣 光正
    原稿種別: 論文
    2020 年 57 巻 12 号 p. 627-632
    発行日: 2020/12/10
    公開日: 2021/02/13
    ジャーナル フリー

    Grinding machines are a main force in grinding work and various types of grinding machines have been developed and used. In today’s industry, where particles need to be ground down to smaller size than ever before, utilization of bead mills, a type of agitated media mill, can be an effective grinding method. On the other hand, not enough study has been made on the bead mill because it is still new in the history of the grinding machine. In this study, grinding tests were thus conducted with a dry-type bead mill, using different sizes of beads. As a result, the distribution of particle diameters changed in a similar way, regardless of the bead size, as the grinding proceeded. Further, for all bead diameters, the relationship between specific energy and median diameter followed the same rule, which demonstrated that use of smaller beads increases energy efficiency in relative terms.

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