Oxonium and ammonium ion-exchange

Fig- 33.3. Fracture-surface microstructurc parallel to the pressing direction for textured P -AhO.,. 

The field-assisted current is passed through a sample immersed in 10% HAC at 80 °C. The resultant current-time curves for different applied voltages are shown in Fig. 33.4. Possible sources of sample resistivity are  

The low /(P) levels ( 0.1) of 8N4 reduce the first mechanism to a minor role. Interruption of the power supply resulted in a residual potential of 2 V in the same direction as the applied voltage. This can be generated only by development of a cation concentration gradient through the sample section. As K moves towards the cathode, HjO enters from the anolyte. If more K exits than slower H30 enters, the developing polarization will slow down and stop the exit. As a 

Another possible resistivity source is the development of an layer 

Field-reversal led to increased current levels (Fig. 33.5). The polarity-reversed sample was completely ion-exchanged after 35 days under 20 V (as opposed to 50 days for single-direction current flow). This result suggests dissipation of anion layers in the liquid at the electrolyte surfaces eliminates fields opposing the applied field. 

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