Abstract: The invention provides a process for preparing magnetic recording material by depositing ferromagnetic material in particulate form into an aluminum substrate. The aluminum substrate is prepared by cleaning an aluminum or aluminum metal containing substrate; anodizing the cleaned metal substrate, to produce a suitably pitted or porous oxide substrate surface; and rinsing the anodized substrate, substantially to remove therefrom acid residues remaining from the anodizing step. The substrate in contact with a liquid solution of a salt of at least one ferromagnetic metal is then subjected to electrolysis with alternating current, to deposit the metal into the pores of the oxide in small-particle, ferromagnetic form while adjusting and controlling the frequency of the alternating current to obtain discrete particles in the pores assembled in an anisotropic configuration. Excess liquid solution is subsequently removed from the so-treated substrate.