溶銅中への硫黄, セレン, テルルの相互拡散

Abstract

Chemical inter-diffusion coefficients of sulfur, selenium, and tellurium in liquid copper have been measured with the modified capillary reservoir method in the temperature range from 1, 100°to 1, 300°C. Several liquid Cu-S Cu-Se, and Cu-Te alloys ranging in composition from 0.2 to 0.8 wt% S, from 0.5 to 3. 0 wt% Se, and 5.0 wt%Te were used as the liquid alloys for reservoir. From the re-examination of the applicability of simplified equations for the calculation of diffusion coefficient, it was found that the equation derived by Derge et. al. can only be used when the ratio ofCa/Cs, ratio between the average concentration of sample-Caand the concentration of reservoir liquid Cs, is less than 0.6 or, θ(=π2Dt/4l2)<0.7. Experimental error due to the chemical analysis of sample increases with the decreasing ratio ofCa/Cs. To obtain accuratediffusion coefficients by the use of this simplified equation, the experimental condition should be controlled so that the ratio ofCa/Csis in the range from 0.4 to 0.6. Results obtained are summerized as follows:1) The diffusion data fit the following Arrhenius type equations; for sulfurDc=2.0×10-2exp (-14, 500/RT) cm2/secQ=14.5±1.4kcal/molefor seleniumDc=4.0×10-3exp (-11, 900/RT) cm2/secQ=11.9±1.6kcal/molefor telluriumDc=3.4×10-3exp (-12, 800/RT) cm2/secQ=12.8±2.3kcal/mole2) The diffusivity increases (DS>DSe>DTe) with the decreasing radius of diffusing particle (rs<rse<rTe).