The self-diffusion of 54Cr and 50Cr isotopes in monocrystals was studied by using ion implantation and thick-film methods. The concentration profiles were determined by using secondary ion mass spectrometry, and the diffusivities were calculated by using a solution to Fick's law which took account of evaporation and exchange at the surface. It was found that both methods indicated diffusion coefficients which were of the same order of magnitude, and could be described by:

D (cm2/s) = 5.84 x 10-9 exp[-280(kJ/mol)/RT

The values were lower than published ones, and did not depend upon the O pressure (table 50).

A.C.S.Sabioni, B.Lesage, A.M.Huntz, J.C.Pivin, C.Monty: Philosophical Magazine A, 1992, 66[3], 333-50

 

 

 

Table 50

Diffusion of Cr in Cr2O3

 

Temperature (C)

Method

PO2 (atm)

D (cm2/s)

1300

ion implantation

5.0 x 10-5

6.1 x 10-18

1200

thick film

5.0 x 10-5

1.0 x 10-18

1300

thick film

5.0 x 10-5

4.8 x 10-18

1300

thick film

6.9 x 10-7

4.7 x 10-18

1300

thick film

1.3 x 10-8

2.2 x 10-18

1300

thick film

1.3 x 10-10

3.1 x 10-18

1300

thick film

3.0 x 10-13

5.8 x 10-18

1350

thick film

5.0 x 10-5

3.7 x 10-18

1400

thick film

5.0 x 10-5

9.0 x 10-18

1450

thick film

5.0 x 10-5

6.3 x 10-17