Corrosion-resistant permanent magnet and intravascular blood pump comprising the magnet

An intravascular blood pump, comprising:

• a pump casing having a blood flow inlet and a blood flow outlet;
• an impeller rotatably supported at least partially within the pump casing;
• an electric motor coupled to the impeller to drive rotation of the impeller, the electric motor including a corrosion-resistant permanent magnet comprising:
• a magnet body, and
• a composite coating provided on and covering surfaces of the magnet body, the composite coating comprising a first layer structure on the magnet body, and, optionally, a second layer structure on the first layer structure, each layer structure comprising, in the order recited, an inorganic layer,
• a linker layer on the inorganic layer,
• an organic layer formed from poly(2-chloro-p-xylylene) on the linker layer, wherein
• the inorganic layer of the first layer structure either comprises an aluminum layer on the magnet body, or comprises an aluminum layer on the magnet body and an aluminum oxide layer on the aluminum layer, and
• the inorganic layer of the second layer structure comprises at least one of an aluminum layer or an aluminum oxide layer, and
• the composite coating has at least one aluminum oxide layer having a thickness of at least 50 nm.

A method of using an intravascular blood pump, the method comprising:

• moving the intravascular blood pump to a desired location via a flexible catheter coupled to the intravascular blood pump, the intravascular blood pump including:
• a pump casing having a blood flow inlet and a blood flow outlet;
• an impeller rotatably supported at least partially within the pump casing;
• an electric motor coupled to the impeller to drive rotation of the impeller, the electric motor including a corrosion-resistant permanent magnet comprising:
• a magnet body, and
• a composite coating provided on and covering surfaces of the magnet body, the composite coating comprising a first layer structure on the magnet body, and, optionally, a second layer structure on the first layer structure, each layer structure comprising, in the order recited,
• an inorganic layer,
• a linker layer on the inorganic layer,
• an organic layer formed from poly(2-chloro-p-xylylene) on the linker layer,
• wherein
• the inorganic layer of the first layer structure either comprises an aluminum layer on the magnet body, or comprises an aluminum layer on the magnet body and an aluminum oxide layer on the aluminum layer, and
• the inorganic layer of the second layer structure comprises at least one of an aluminum layer or an aluminum oxide layer, and
• the composite coating has at least one aluminum oxide layer having a thickness of at least 50 nm;
• and
• energizing electrically conductive windings of the electric motor to generate force to drive rotation of the impeller.