An inner drive for a magnetic drive pump includes a magnet supported on a yoke. The inner drive is driven about an axis to pump a corrosive process fluid. The magnet and yoke are fully encapsulated during the molding process to completely surround the magnet and yoke in a protective plastic shell. A sleeve is arranged radially outwardly of the magnet to provide further protection. Backing rings are arranged on either side of the magnet. A bonding material joins the plastic shell to the backing rings and sleeve to prevent a space from forming beneath the plastic shell that would become filled with the process fluid once it has permeated the plastic shell. A protective coating is arranged on at least a portion of the magnet to further insulate the magnet from the process fluid.