Abstract
Electrophoretic deposition of Al2O3 insulation films on tungsten coils was studied by using an in-situ observation technique of the deposition process.
Morphological changes of the gel-like hydroxide deposits that were formed on tungsten coils were studied in relation to the electrolyte content of the water-ethanol suspension medium.
Tungsten surfaces were covered with gel-like deposits containing Al2O3 particles immediately when the current was passed between tungsten cathode and pure aluminum anode in the water-ethanol suspension medium containing Al3+ and Mg2+ ions. The gel-like deposits were hydroxides of Al and Mg. The shape of gel-like deposits covering tungsten coils changed with the content of Al3+ and Mg2+ ions.
The thickness of the deposit decreased with increasing Al3+ ion content and increased with increasing Mg2+ ion content of the suspension.
