Design of a C/SiC functionally graded coating for the oxidation protection of C/C composites

• Published in: Carbon (New York) Vol. 43; no. 8; pp. 1749 - 1757
• Main Authors: Kim, J.I., Kim, W.-J., Choi, D.J., Park, J.Y., Ryu, W.-S.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-07-2005; Elsevier Science
• Subjects: Carbon/carbon composites; Chemical vapor deposition; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Materials science; Oxidation; Physics; Specific materials; Chemical vapor deposition; Oxidation; Carbon/carbon composites; Design; Composite materials; Silicon Carbides; Carbon; Protection
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2005.02.025

To reduce the residual thermal stress between the carbon fiber-reinforced carbon (C/C) composites and the SiC coating layer, functionally graded materials (FGM) consisting of a C/SiC compositionally graded layer (C/SiC interlayer) were adopted. After designing the compositional distribution of the C/SiC interlayer which can relieve the thermal stress effectively, the deposition conditions of the entire compositional range of the C/SiC composites were determined using a thermodynamic calculation. According to the design and calculation the C/SiC interlayer and the SiC outer layer were deposited on the C/C composites by a low pressure chemical vapor deposition (LPCVD) method at deposition temperatures of 1100 and 1300
°C. The stress calculation and the experimental results suggested that the SiC-rich compositional profile in the FGM layer is the most effective for relieving the thermal stress and increasing the oxidation resistance.