Agglomeration of thin platinum films on a zirconia substrate

Thin films of Pt (100-200 nm) were sputtered onto a zirconia substrate and annealed for several days at 700 degrees C. Agglomeration occurred accompanied by loss of continuous electronic conduction for surface coverages below a critical level. AC impedance analysis showed that at elevated temperatures conduction across the surface involved a mixed mechanism of electronic conduction in the metallic islands and ionic conduction in the electrolyte between the islands.