Anomalous diffusion of hydrogen in fused quartz glasses for lamps above 800°C

抄録

To clarify the mechanism of hydrogen diffusion in fused quartz at elevated temperatures over 800°C, a mass filter was used to measure diffusion coefficients, permeabilities and solubities of hydrogen in several types of fused quartz tubes. The diffusion coefficient obtained at 800°C was 2-3×10^-6 cm²/sec, and the activation energy of the hydrogen diffusion at 400°-800°C was 11.6 Kcal/mol. These values are in good agreement with the values previously reported. Precise measurements at temperatures abobe 800°C resulted in diffusion anomaly, or an unusual fall-off of diffusion coeffusion coefficient, while premeabilities kept monotonous increase with rising temperature. In consequence the solubilities, obtained from the coefficient and permeability, showed a sharp increase up to 2×10¹⁹ molecules/cm³.