Formation of a chromium-carbide conversion coating on silicon carbide

Journal Article · Sat Oct 01 04:00:00 EDT 1994 · Oxidation of Metals; (United States)

DOI:https://doi.org/10.1007/BF01052022· OSTI ID:6735155

Kung, S C ^[1]

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1. Babcock Wilcox Co., Alliance, OH (United States)

The formation of a chromium-carbide conversion coating on SiC was achieved using the pack-cementation technique. The conversion coating is intended to improve the corrosion resistance of SiC and its derivatives, such as SiC-base continuous fibers and composites, by forming a protective Cr[sub 3]O[sub 3] scale upon exposure to high-temperature corrosive environments. Different pack chemistry and processing parameters were evaluated in the laboratory. Results indicated that the coating morphologies and compositions achieved were significantly affected by variation of these processing factors. In this paper, the conversion coating obtained from one of the systems investigated is reported. The coating consists of a multilayered structure with each of the sublayers containing a high-Cr concentration. In addition, the coating surface is relatively dense and pore free compared to the underlying SiC substrate material. A dense and pore-free morphology is highly desirable for coating applications, especially on porous substrates. The multilayered coating structure consists of the following sublayers: Cr[sub 23]C[sub 6]/Cr[sub 7]C[sub 3]/Cr[sub 7]C[sub 2]+Cr[sub 3]Si/Cr[sub 5]Si[sub 3]C[sub x]/SiC substrate.

• OSTI ID: 6735155
• Journal Information: Oxidation of Metals; (United States), Journal Name: Oxidation of Metals; (United States) Vol. 42:3-4; ISSN OXMEAF; ISSN 0030-770X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360205* -- Ceramics
Cermets
& Refractories-- Corrosion & Erosion
CARBIDES
CARBON COMPOUNDS
CHROMIUM CARBIDES
CHROMIUM COMPOUNDS
COATINGS
CORROSION PROTECTION
DEPOSITION
PROTECTIVE COATINGS
SILICON CARBIDES
SILICON COMPOUNDS
SURFACE COATING
TRANSITION ELEMENT COMPOUNDS