Electrophoretic deposition of thin alumina films from water suspension

Alumina water suspensions have been prepared for thin alumina film deposition on steel. The type and quantity of deflocculant have been determined using zeta potential and viscosimetric measurements. The deposition was performed under the constant deposition voltage between 30 and 250 V. The morphology of electrodeposited alumina films was investigated using the optical microscopy coupled with image analysis, which enables the determination of pore number, percentage of film surface covered by pores and mean pore diameter, and scanning electron microscopy (SEM). It was shown that alumina films of the highest thickness and the lowest porosity can be formed at lower applied voltage and for longer deposition time. The minimum of alumina films porosity, obtained at the lowest deposition voltage of 30 V, can be explained by smaller amount of evolved hydrogen on the cathode during electrodeposition process.