A plating bath for the electroless coating of magnetic recording media substrates includes cobalt, nickel, and zinc metal ions in a buffered solution including a reducing agent, a strong base, and chelating agents. Typically, the reducing agent will include phosphorous which will form a portion of the ferromagnetic layer being deposited on the substrate. By utilizing malic acid or a malate salt as a chelating agent, magnetic media having improved signal-to-noise ratios, switching field distributions, and corrosion resistance, have been obtained.