Ion migration on pyrolytic silicon dioxide in a humid medium

Measurements have been made on the mobility $\mu$ of ions on pyrolytic $SiO_2$ films at elevated humidity. It is found that $\mu$ is very much dependent on the $SiO_2$-film production temperature. It is considered that the main reason for this is increase in the microporositу as the pyrolysis temperature is reduced. It is concluded that the use of pyrolytic $SiO_2$ films as protective coatings will be effective only for sufficiently low degrees of microporosity.