Metallurgy, Vol. 42 No. 4, 2003.
Original scientific paper
Aluminium Protective Coatings Produced on Creep-Resisting Steel Directly in a Casting Mould
J. Kubicki
B. Piekarski
Abstract
The structure of coatings and their ability to protect the castings made of G-X25NiCrSi 36-17 (DIN 17006) cast steel against carburization have been described. Al-Cu and Al-Si protective coatings, produced directly in a casting mould, have a considerable thickness (400 - 2000 µm), and complex multiphase structure. Its main structural constituents are: (Fe, Ni, Cr), (Fe, Ni, Cr), Al(Ni, Fe), carbides M23C6 and M7C3. In Al-Si ferritic coatings are also present: (Ni, Fe), (Fe, Al, Ni, Cr) and (Cr, Si)3Ni2Si. Carburisation changes substantially the structure of coatings, what results in an increase of the amount of (Fe, Ni, Cr) or (Ni, Fe) and carbides, and a decrease of the amount of (Fe, Ni, Cr) and Al(Ni, Fe). Apart from above mentioned changes, the investigated coatings reduce the carbon diffusion by 20 - 65 % Al-Cu, about 55 % Al-Si (austenitic), and 75 % Al-Si (ferritic), so they can provide a temporary protection against high-temperature corrosion.
Keywords
Hrčak ID:
128394
URI
Publication date:
1.10.2003.
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