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The Kinetics of Grain-Boundary Groove Growth on Alumina Surfaces

  • Wayne M. Robertson
  • Roger Chang
Conference paper
Part of the Materials Science Research book series (MSR)

Abstract

The growth of grain-boundary grooves on polished surfaces of polycrystalline aluminum oxide has been studied over the temperature range 1100–1700°C. Groove widths were measured interferometrically after annealing in air for varying times. From the kinetics of groove growth, it is shown that diffusion on the crystal surfaces controls the process. The surface diffusion coefficient (in cm2/sec) is given by the relation
$$D_s \, = \,\left( {7 \pm 5} \right)\, \cdot \,10^2 \,\exp \,\left[ { - \left( {75,000 \pm 5,000} \right)/RT} \right]$$
The surface diffusion coefficient at 1600°C is about 10−6 cm2/sec, which is nearly six orders of magnitude larger than the lattice diffusion coefficient of aluminum ions and from seven to nine orders of magnitude larger than that of oxygen ions at this temperature. Lattice diffusion does not contribute appreciably to the formation of grain-boundary grooves. Possible mechanisms of surface diffusion on aluminum oxide are discussed.

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Copyright information

© Springer Science+Business Media New York 1966

Authors and Affiliations

  • Wayne M. Robertson
    • 1
  • Roger Chang
    • 1
  1. 1.North American Aviation Science CenterThousand OaksUSA

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