Diffusion of Argon in a Potassium‐Lime‐Silica Glass

Diffusion coefficients for bulk diffusion of argon in a potassium‐lime‐silica glass have been determined at temperatures in the range 308° to 470°C. by a radioactive counting technique. Argon diffusion was found to follow classical bulk diffusion theory within the limits of experimental accuracy. From a plot of log D versus 1000/ T , an activation energy of 42 kcal. per mole was obtained for the argon diffusion process. The activation energy and diffusion coefficients obtained for argon by the radioactive counting technique are compared with values for helium and argon obtained by other investigators by use of the permeation technique.