bonding geometries are disclosed between permanent magnets and steel portions of magnetic assemblies . when employed in permanent magnet motors , this particular bonding construction reduces or even eliminates the loosening of permanent magnets inside of electric motors . the bonding geometry consists of interlocking protrusions and voids at the bonding interface . a bonding agent is employed that may be filled with finely divided iron or other magnetic material . the result is a strong bond between the permanent magnet and steel assembly portions with virtually no loss in overall magnetic properties .