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ZIRCONIUM BORIDE/BORON CARBIDE COMPOSITE AND METHOD FOR MANUFACTURING SAME

Foreign code F210010284
File No. (S2019-0386-N0)
Posted date 2021年1月28日
Country 世界知的所有権機関(WIPO)
International application number 2020JP006751
International publication number WO 2020202878
Date of international filing 令和2年2月20日(2020.2.20)
Date of international publication 令和2年10月8日(2020.10.8)
Priority data
  • 特願2019-070753 (2019.4.2) JP
  • 特願2019-154503 (2019.8.27) JP
Title ZIRCONIUM BORIDE/BORON CARBIDE COMPOSITE AND METHOD FOR MANUFACTURING SAME
Abstract To provide: a high-density zirconium boride/boron carbide composite having a Vickers hardness Hv of 23 GPa or more and a fracture toughness value KIC of 9.0 MPa•m1/2 or more, said zirconium boride/boron carbide being represented by ZrB2/B4C; and a method for manufacturing the same. The method according to the present invention comprises: a step for preparing a starting material by mixing an amorphous boron powder with an amorphous carbon powder to give a molar ratio B:C of (3.6-6.5):1; a step for weighing a ZrB2 powder in such an amount as to give a theoretical ratio by volume to B4C, which is synthesized from the starting material, ZrB2/B4C of 10/90-60/40 vol% and mixing with the starting material to give a mixed powder; and a step for molding the mixed powder using a die to give a molded article and then sintering the obtained molded article to thereby simultaneously synthesize and sinter the ZrB2/B4C composite.
Outline of related art and contending technology BACKGROUND ART
Zirconium boride (ZrB2), which is an ultra-high temperature heat-resistant ceramic (UHTC) recently attracting attention in the field of engineering ceramics, is a covalent material having a high melting point of Tm = 3200 °C. and is expected to be UHTC for space aircraft at present, but it is difficult to produce dense and high-density sintered compact because of being a difficult-to-sinter material. For example, Patent Document 1 below discloses a method for producing tungsten-added ZrB2 by wet-mixing a predetermined amount of Zr powder, a predetermined amount of tungsten (W) powder, and a predetermined amount of B powder, press-molding the mixture to form a compact, and subjecting the compact to discharge plasma sintering (another name: pulse energization press-sintering). However, the Vickers hardness (Hv) of the sintered compact obtained by using such a manufacturing method is 20.7 GPa at the maximum, and it is desirable to further improve the mechanical properties, and particularly to further improve the strength at high temperatures.
For UHTC which can be used in the atmosphere, the preparation of composites of ZrB2/SiC, ZrB2/B4C, ZrB2/LaB6 based mainly on ZrB2 of metal boride has been studied, however, high melting point compounds are difficult to sinter due to covalent bonding, It is difficult to produce a high-density sintered compact, and it is difficult to produce a high-density sintered compact even if a pulse energization pressure sintering method (Pulsed Electric-current Pressure Sintering: PECPS) suitable for producing a high-density sintered compact of a hard-to-sinter material is used.
Boron carbide (B4C) is known as a material having a light weight (theoretical density Dx = 2.515 Mg · m-3) and a high melting point (Tm = 2450 °C), Since the cubic boron nitride (c-BN) has a hardness (Vickers hardness Hv: 29 ~ 33 GPa) next to cubic boron nitride (c-BN), a composite composed of both ZrB2 and B4C is also one of the possible materials for use as UHTC. However, since B4C is also a covalent hard sintering material, a high temperature and high pressure of 2050 ~ 2150 °C./30 ~ 50 MPa is required for the preparation of ZrB2/B4C composite added to ZrB2, resulting in a high cost production, and there are few reports on the preparation.
  • Applicant
  • ※All designated countries except for US in the data before July 2012
  • THE DOSHISHA
  • Inventor
  • HIROTA Ken
  • KATO Masaki
  • MIYAMOTO Hiroyuki
  • Tung Duy Le
IPC(International Patent Classification)
Specified countries National States: AE AG AL AM AO AT AU AZ BA BB BG BH BN BR BW BY BZ CA CH CL CN CO CR CU CZ DE DJ DK DM DO DZ EC EE EG ES FI GB GD GE GH GM GT HN HR HU ID IL IN IR IS JO JP KE KG KH KN KP KR KW KZ LA LC LK LR LS LU LY MA MD ME MG MK MN MW MX MY MZ NA NG NI NO NZ OM PA PE PG PH PL PT QA RO RS RU RW SA SC SD SE SG SK SL ST SV SY TH TJ TM TN TR TT TZ UA UG US UZ VC VN WS ZA ZM ZW
ARIPO: BW GH GM KE LR LS MW MZ NA RW SD SL SZ TZ UG ZM ZW
EAPO: AM AZ BY KG KZ RU TJ TM
EPO: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
OAPI: BF BJ CF CG CI CM GA GN GQ GW KM ML MR NE SN ST TD TG

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