受賞記念講演:平成12年度技術進歩賞 Development of Pressureless Sintered Titanium Boride Ceramics (特集 硬質材料) Development of Pressureless Sintered Titanium Boride Ceramics

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Abstract

The boride ceramics have been attracting considerable attention as one of the newest advanced ceramics. In particular, titanium diboride (TiB<SUB>2</SUB>) has various desirable properties, such as a high melting point (3253 K), high hardness (32 GPa), and moderate electrical conductivity (10<SUP>5</SUP>S). One of its major disadvantages, however, is poor sinterability. In this study, the effect of sintering aids addition on the pressureless sintering process of TiB<SUB>2</SUB> ceramics was investigated. The addition of both Cr and C or Cr<SUB>3</SUB>C<SUB>2</SUB> as the sintering aids accelerated the densification of TiB<SUB>2</SUB> significantly. Simultaneous addition of about 5 to 10 mass% Cr and C or Cr<SUB>3</SUB>C<SUB>2</SUB> resulted in high density, high bending strength and high Vickers hardness. According to the X-ray diffraction data of TiB<SUB>2</SUB> composites fired at 1173 to 2173 K showed that Cr and C or Cr<SUB>3</SUB>C<SUB>2</SUB> reacted with TiB<SUB>2</SUB> to form CrB and TiC during the sintering process. CrB and TiC were formed at the grain boundaries of TiB<SUB>2</SUB>. Also, the solid solution between TiB<SUB>2</SUB> and sintering aids was recognized. The SEM micrograph observation supported that a liquid phase was significantly concerned in the sintering of TiB<SUB>2</SUB>. The fracture surface of TiB<SUB>2</SUB> sintered body showed both transgranular and intergranular fracture mode. It is considered that the addition of both Cr and C or Cr<SUB>3</SUB>C<SUB>2</SUB> was effective in promoting the bonding between grains and removing pores to achieve high density in the sintered body. Thus, a sintered body of TiB<SUB>2</SUB> having increased density, high strength and high hardness can be obtained by the addition of Cr and C or Cr<SUB>3</SUB>C<SUB>2</SUB> to TiB<SUB>2</SUB>.

Journal

  • Journal of the Japan Society of Powder and Powder Metallurgy

    Journal of the Japan Society of Powder and Powder Metallurgy 49(4), 318-322, 2002-04-15

    Japan Society of Powder and Powder Metallurgy

References:  32

Codes

  • NII Article ID (NAID)
    10008222616
  • NII NACSIS-CAT ID (NCID)
    AN00222724
  • Text Lang
    ENG
  • Article Type
    REV
  • ISSN
    05328799
  • NDL Article ID
    6146291
  • NDL Source Classification
    ZP41(科学技術--金属工学・鉱山工学)
  • NDL Call No.
    Z17-274
  • Data Source
    CJP  NDL  J-STAGE 
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