Mechanical circulatory support pump drive with corrosion protection

A blood pump, comprising:

• an impeller;
• a drive shaft coupled to the impeller and configured to rotate with the impeller, the drive shaft defining a longitudinal axis;
• a rotor integrated with the impeller and configured to rotate with the drive shaft, the rotor comprising a driven magnet having an outer surface including a first surface facing the impeller and an opposing second surface;
• a corrosion-resistant coating disposed on the outer surface of the driven magnet;
• a motor configured to drive the rotor, causing the rotor to rotate;
• a protection assembly disposed adjacent the motor and configured to receive a convex end of the drive shaft, the protection assembly comprising a protection assembly housing defining a protective fluid chamber, the protective fluid chamber sealed around the driven magnet and a bearing, the bearing comprising a bearing face including a concave depression receiving the convex end of the drive shaft within the protective fluid chamber, the bearing face being longitudinally spaced apart from the second surface of the driven magnet and defining a gap therebetween, the bearing being disposed between the motor and the driven magnet, the protection assembly housing comprising a cup washer having a base and peripheral wall extending away from the base, forming the protective fluid chamber bounded, in part, by an inner surface of the peripheral wall and an inner surface of the base;
• an impeller assembly housing comprising a cylindrical wall defining an internal chamber, the driven magnet and the impeller being disposed within and configured to rotate relative to the impeller assembly housing, and the protection assembly housing disposed within the internal chamber;
• wherein the entire bearing is disposed within the protective fluid chamber of the protection assembly housing.