The system was studied at 300 to 600C by using diffusion couples, and the effects of composition, temperature and Hg over-pressure were determined (figure 29). Significant differences were found in the behaviour of the interdiffusion coefficients in 2 temperature ranges. A dual mechanism was proposed for diffusion at temperatures greater than 450C; with a vacancy mechanism and an interstitial mechanism predominating at low and high x-values, respectively, and an interstitial mechanism predominating at lower temperatures.

M.S.Tang, D.A.Stevenson: Applied Physics Letters, 1987, 50[18], 1272-4