Synthesis of $TiB_2-Al_2O_3$ Composite by Self-Propagating High Temperature Synthesis (SHS) and Its Pressureless Sintering

SHS법에 의한 $TiB_2-Al_2O_3$계 복합물의 합성 및 상압소결에 관한 연구

  • 최상욱 (인하대학교 무기재료공학과) ;
  • 조동수 (인하대학교 무기재료공학과) ;
  • 김세용 (인하대학교 무기재료공학과) ;
  • 남건태 (인하대학교 무기재료공학과)
  • Published : 1994.05.01

Abstract

A composite of TiB2-Al2O3 system was successfully prepared from a mixture of TiO2, B2O3, and Al by self-propagating high temperature synthesis (SHS) with a novel characteristic, utilizing the internal oxidation heat of aluminium metal of the mixture, instead of by a conventional technique, externally heating a mixture of Ti, B and Al2O3. From a mixture with B/Ti molar ratio of =2.0, pure two phases of TiB2 and $\alpha$-Al2O3 with good crystallinity and small, uniform sizes were formed. However, when the B/Ti molar ratio of the mixture goes to a value less than 2.0, in addition to the above main minerals, a small smounts of metastable phases such as TiB and Ti3B4 were formed. It was found that about 60%, the optimum green density of compacts gave their highest reaction rate and temperature during SHS process. TiB2-Al2O3 system composite with B/Ti molar ratio of =2.0 could be pressurelessly sintered even at 190$0^{\circ}C$ under Ar gas flows without any addition of sintering aids, showing their good properties such as 91.2% in relative density, 2750 kgf/$\textrm{mm}^2$ in Vickers hardness and 2620 kgf/$\textrm{cm}^2$ in flexural strength.

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References

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