The kinetics of thermal grooving, at the intersection of rhombohedral twin boundaries with the (1010) plane, were measured from 1773 to 2273K. Analysis of the data, using the Mullins model, showed that surface diffusion was the predominant mechanism for mass transport. The results could be described by:

D (cm2/s) = 4.05 x 105 exp[-452(kJ/mol)/RT]

Surface Mass Transport of Alumina. A.R.Gaddipati, W.D.Scott: Journal of Materials Science, 1986, 21[2], 419-23

 

Table 1

Surface Diffusivity on Polycrystalline Al2O3

 

Temperature (K)

Atmosphere

D(cm2/s)

1273

air

1.73 x 10-11

1431

air

2.49 x 10-10

1573

air

1.72 x 10-9

1736

air

1.02 x 10-8

1273

vacuum

1.18 x 10-11

1573

vacuum

1.05 x 10-9

1736

vacuum

7.39 x 10-9

1273

Ar

1.44 x 10-11

1431

Ar

1.87 x 10-10

1573

Ar

1.82 x 10-9

1736

Ar

1.02 x 10-8