To provide a protective coating for oxidizable investment casting core.
A substrate (50) is coated by applying a first layer of an esseentially pure aluminum on the surface of the substrate (50), and at least a first portion in the first layer is oxidized so as to provide the protective coating (54) of desired nature. The substrate (50) can be made to a heat resistant metal based investment casting core (38), and the internal surface (60) of the coating system and the first layer (52) is positioned at on the outer surface of the substrate (50), and the outer surface (62) of the coating system and a second layer (54) is provided with the outer surface of RMC (38) (Refractory Metal Core). A transition part (64) separates the first layer (52) from the second layer (54) and the transition part (64) can be made considerably steep. The coating systems (52, 54) have the thickness (T1) and the first layer (52) has the thickness (T2) and the second layer (54) has the thickness (T3).
LOMASNEY GARY M
PERSKY JOSHUA E
Tomioka Kiyoshi
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