The Ablation and Oxidation Behaviors of SiC Coatings on Graphite Prepared by Slurry Sintering and Pack Cementation

Journal Article · Wed Aug 15 04:00:00 EDT 2018 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-018-3462-Z· OSTI ID:22860357

Aliasgarian, Reza; Naderi, Malek; Mirsalehi, Seyyed Ehsan ^[1]; Safi, Saeed ^[2]

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1. Amirkabir University of Technology, Department of Mining and Metallurgical Eng (Iran, Islamic Republic of)
2. Materials and Energy Research Center, Ceramic Department (Iran, Islamic Republic of)

SiC coatings were generated on graphite using slurry sintering (SS) and pack cementation (PC). The samples’ ablation features were assessed by an oxyacetylene torch. The rates of mass ablation of the PC–SiC and SS–SiC coatings were approximated 2.17 × 10{sup −3} and 9.52 × 10{sup −3} g s{sup −1}, respectively, decreased by 84.1 and 29.6% compared to the uncoated samples. It was mainly attributed to the formation of a SiO{sub 2} layer on the surface. The continuous SiO{sub 2} molten film formed via the PC–SiC oxidation generates a sealing mechanism which can be an obstacle against the oxygen diffusion and hinder more ablation. This is while discontinuous SiO{sub 2} film formed from the thin SS–SiC cannot protect the graphite effectively. The non-isothermal oxidation test shows that without the SiC coating, the sample weight is lost largely from 25 to 1500 °C, and its weight loss was 2.2% after the TGA. However, after coating, the samples possessed excellent oxidation protection and weight losses of SS–SiC and PC–SiC coatings are down to 1.3 and 0.6%, respectively. The more oxidation of the graphite substrate occurred due to the formation of macrocracks in the coating during the TGA and also the formation of holes on SiO{sub 2} glass layer owing to release of CO or CO{sub 2}.

• OSTI ID: 22860357
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 8 Vol. 27; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBON DIOXIDE
CARBON MONOXIDE
COATINGS
COMPARATIVE EVALUATIONS
DIFFUSION
FILMS
GLASS
GRAPHITE
LAYERS
OXIDATION
SILICON CARBIDES
SILICON OXIDES
SINTERING
SUBSTRATES
SURFACES
THERMAL GRAVIMETRIC ANALYSIS