Chemical Diffusion In Ce-based Glass-forming Melts

The chemical diffusion coefficient is measured in Ce-Ni binary and Ce-Al-Niternary amorphous alloy melts by use of our self-designed sliding cell method. Arelatively slow diffusion behavior is found in both alloy melts. In the diffusionexperiments in Ce-Ni binary alloy melts with a small concentration gradient, wediscussed the effect of thermodynamic factor on chemical diffusivity by employing theDarken equation and self-diffusivity measured by other researchers. An obviously"strengthening" effect is found on the chemical diffusion coefficient. In general, thispaper considers Darken equation is an approximate formulas to describe diffusionphenomena in Ce-Ni binary alloy melts. In addition, in the diffusion experiments inCe-Ni binary alloy melts with a big concentration gradient, by using the Boltzmannsolution, one achieved the Ni concentration dependent of the chemical diffusioncoefficient. With this data, we obtained the concentration dependent of self-diffusioncoefficient by use of the Darken equation, which is comparable with the measuredself-diffusion result. So this is another evidence for the applicable of Darken equationin Ce-Ni melts. But one thing we should point out is the physical diffusion mechanismremains to be further studied.In the Ce-Al-Ni ternary alloy melts, this paper analyzes the impact of the thirdelement Ce on the chemical diffusion of Al-Ni. Combined with the measured results inCe-Ni binary alloy melt, we studied the difference of chemical diffusion coefficientwhen substitute Ce by Al. And one also explored the relations between glass-formingability and chemical diffusion coefficient. Generally, the glass-forming ability andchemical diffusion coefficient in melts is inversely correlated.