ISSN:
1573-4870
Keywords:
Alumina
;
surface
;
kinetics
;
diffusion
;
SALK
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The kinetics of shape evolution of a completely faceted crystal/internal void by surface diffusion was modeled. Arrays of micron-sized cavities were generated in sapphire substrates with known surface orientations using microlithography and ion beam etching and converted to internal intragranular pores of nonequilibrium shape by diffusion bonding of the etched substrate to an identical-orientation unetched sapphire substrate. Pore shape evolution rates during high-temperature anneals were monitored and found to be highly sensitive to the orientation of the substrate surface. The observed evolution rates were compared with the predictions of the kinetic model using diffusivity values for alumina that span the range from the highest to the lowest diffusion constants reported in the literature. The comparison suggests that surface-attachment-limited kinetics (SALK) play a major role in surface mass transport on stable low-index planes of alumina.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1022665418505
