X-ray energy analysis of Hg diffusion in Ag3Sn amalgams

Publisher Website
Google Scholar
Abstract
Mercury diffusion in the various phases of dental amalgams is a matter of considerable importance with regard to mechanical strength and corrosive properties. At a sufficiently early stage of the diffusion of a diffusant into a diffusate it is appropriate to treat even very small diffusate particles as semi‐infinite bodies. Using this idea, we discuss a convenient general scheme for determining the diffusion coefficient D from a profile of relative diffusant concentration C/Cs vs depth x from the surface where a constant concentration Cs exists. If the initial concentration is zero, the result of the method is that a plot of x vs erf−1 (1−C/Cs) should be a straight line through the origin and that the slope should be (4D t)1/2. X‐ray energy dispersion spectrometry provides data well suited for analysis by the theoretical method. We have made analyses for Hg diffusion into Ag3Sn over a range of temperature so that D, D0, and ED from the relation D =D0e−ED/RT were obtained. The results are D0 =4.20 cm2/sec and ED =78±6 kJ/mol (18.6±1.5 kcal). At 37°C, D =3.2×10−13 cm2/sec.

This publication has 6 references indexed in Scilit: