Method to increase corrosion resistance in ferritic nitrocarburized treated cast iron substrates
AssigneeGM Global Technology Operations LLC
InventorsMichael D. Hanna, Michael L. Holly
Life of this patent
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Abstract
A method for improving corrosion resistance in FNC cast iron substrates without the need for additional coating or painting. The exemplary methods remove a portion of the FNC coating applied to a cast iron substrate, preferably through polishing, to expose the epsilon phase portion of the compound area. The epsilon phase portion is thought to provide improved corrosion protection as compared to non-polished FNC cast iron substrates. One exemplary product that may be provided with improved corrosion protection according to the above method is a brake rotor having a FNC treatment.
Claims20
A method for improving corrosion resistance for a cast iron substrate including a nitrocarburized surface treatment, the method comprising:
- applying the nitrocarburized surface treatment to an outer surface of the cast iron substrate to a predetermined depth, the applied nitrocarburized surface treatment including a compound area having a predetermined depth extending from said outer surface;
- and
- removing a portion of said predetermined depth of said compound area to expose a dominant epsilon phase portion.
A method for improving corrosion resistance for a brake rotor, the method comprising:
- applying a nitrocarburized surface treatment to an outer surface of the brake rotor to a predetermined depth, said applied nitrocarburized surface treatment forming a compound area having a predetermined depth extending from said outer surface;
- and
- removing a portion of said predetermined depth of said compound area in a non-frictional area of the brake rotor to expose a dominant epsilon phase portion.
Dependencies are inferred from the claim text.