Chemical diffusion in nonstoichiometric chromium sulfide, Cr2+yS3
Abstract Using the re-equilibration kinetic method the chemical diffusion coefficient in nonstoichiometric chromium sesquisulfide, Cr 2+ y S 3 , has been determined as a function of temperature (1073–1373 K) and sulphur vapour pressure (10−10 4 Pa). It has been found that this coefficient is independent of sulphur pressure and can be described by the following empirical equation: D Cr 2+y S 3 =50.86 exp(-39070 cal/mole/ RT) (cm 2 s −1) . It has been shown that the mobility of the point defects inCr 2+ y S 3 is independent of their concentration and that the self-diffusion coefficient of chromium in this sulfide has the following function of temperature and sulphur pressure: D Cr =2.706×10 2 P −1 4.85 S 2 exp(-56070 cal/mole/ RT) . (cm 2 s −1 ).