Processing of Highly Concentrated Aqueous α-Alumina Suspensions Stabilized with Polyelectrolytes

Authors

  • JOSEPH CESARANO III,

    1. Department of Materials Science and Engineering, and Advanced Materials Technology Program, Washington Technology Center, University of Washington, Seattle, Washington 98195
    Search for more papers by this author
    • Member, the American Ceramic Society.

  • ILHAN A. AKSAY

    1. Department of Materials Science and Engineering, and Advanced Materials Technology Program, Washington Technology Center, University of Washington, Seattle, Washington 98195
    Search for more papers by this author
    • Member, the American Ceramic Society.


  • Presented at the 87th Annual Meeting of the American Ceramic Society, Cincinnati, OH, May 7, 1985 (Basic Science Division, Paper No. 95-B-85).

  • The work summarized in the Background Information section of this paper was sponsored by the Air Force Office of Scientific Research (AFOSR) and the Advanced Research Projects Agency of the Department of Defense and was monitored by the AFOSR under Grant No. AFOSR-083–0375. The work discussed in the main body of this paper was sponsored by the Oak Ridge National Laboratory under subcontract No. 19X-27458C.

Abstract

Stability and rheology of aqueous α-Al2O3 suspensions with poly(methacrylic acid) and poly(acrylic acid) polyelectrolytes were studied as a function of pH, solids loading, and molecular weight. Past work has found polyelectrolyte-stabilized suspensions to be fairly pH independent at low (e.g., 20 vol%) solids loadings. However, we now show that the effective pH range to provide dispersed and fluid suspensions narrows as the concentration of solids increases as related to interparticle forces. At high solids levels, the presence of excess polymer in solution has detrimental effects on stability, which increases as the molecular weight increases. Finally, with knowledge of these concepts, highly concentrated fluid suspensions of 60 vol% Al2O3 (>85 wt%) with submicrometer-size particles have been processed. Higher consolidated densities and reduced sintering temperatures are attained when compared with more conventional processing techniques.

Ancillary