Study of tungsten trioxide reduction in phosphate systems

Reduction of tungsten trioxide with hydrogen in tungsten- phosphate glasses at the temperatures of 500-600 deg C is studied. It is shown that initially the process of reduction is limited by kinetic factors and reduction degree depends linearly on time (tau). After reduction of tungsten trioxide in the glass surface layer the process rate is determined by diffusion of oxygen and tungsten ions to the surface from the glass volume and reduction degree changes proportionally to √tau. On the glass surface a tungsten metal film is formed. According to the change of the glass mass oxygen diffusion coefficients are determined