Massenspektrometrisches Verfahren zur Bestimmung der Sauerstoff-Selbstdiffusion in Gläsern

Abstract

Abstract Mass spectrometric method for determining oxygen self-diffusion in glasses A mass spectrometric method has been developed employing 0 18 labelled oxides in order to study isotope exchange between two different glasses. The method provides self-diffusion coefficients for compact glass materials below the softening points without restrictions of the diffusion annealing time. Concentration profiles were obtained by grinding off thin layers and analysing the ratio of O18 /O16 for each layer. The extraction of oxygen from the glass is based on the reduction by mercuric cyanide at 400 °C to yield carbon dioxide. As an example diffusion profiles of O18 have been measured in samples of two lead glasses. Diffusion coefficients were calculated applying diffusion equations for two-phase systems. The temperature dependence fitted an Arrhenius plot, thus indicating the activation energies. It has been shown that the distribution of O18 is controlled by oxygen self-diffusion and is not affected by the difference in chemical composition of the two glasses nor by physical or chemical solubility of oxygen from air-atmosphere.