Motion of WC Grains in the Liquid Matrix during Liquid Phase Sintering of WC-Co Alloys

WC-Co계의 액상소결시 코발트 액상 내에서 WC 입자의 움직임

  • 김소나 (한국과학기술연구원 세라믹공정센터)
  • Published : 1996.09.01

Abstract

The dispersion of WC grains Into the interior of an eutectic liquid has been studied by superimposing the eutectic WC-85wt.%Co liquid on the top surface of presintered WC-l0wt.%Co alloy compacts. The heavy WC grains diffused into the interior of liquid from the WC-l0wt.%Co compacts. According to increasing the treating temperatures and times, the dispersion distance from WC-l0wt.%Co substrates increased. The fine WC grains diffused into the liquid faster than the coarse WC grains. The high microstructural stability of WC-Co alloys having the heavier WC grains dispersed in a lighter Co-rich liquid was attributed to Brownian motion of WC grains in liquid. The motion of WC grains in the liquid appears to be same with the colloid(the disperse phase) in a dispersing medium. The dihedral angle of 0 degree of WC-Co at. toy seems one of key parameters, which enables the WC-Co alloys to have high structural stability without settling the WC grains during liquid phase sintering.

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References

  1. Trans. AIME v.175 C. S. Smith
  2. Metall. Trans. v.16A H. H. Park;D. N. Yoon
  3. Acta metall. v.31 A. N. Niemi;T. H. Courtney
  4. Metall. Trans. v.15A T. H. Courtney
  5. Principles of Colloid and Surface Chemistry Paul C. Hiemenz
  6. Nature v.187 L. E. Scriven;C. V. Sternling
  7. Modern Devel. Powder Metall. v.12 A. N. Niemi;L. E. Baxa;J. K. Lee;T. H. Coutney
  8. Acta metall. v.33 L. Ratke;W. K. Thieringer