Microstructure and Thermal Properties of Inert Plasma-Sprayed Tungsten Coating on SiC-Coated Carbon/Carbon Composites

Abstract

The coating technology of tungsten on carbon/carbon (C/C) composite is an important issue for fusion experimental device components. In this study, an interlayer of chemical vapor deposition SiC between tungsten coating and C/C substrate was used. A tungsten coating 320 μm thick was successfully deposited on SiC-coated C/C substrate by inert plasma spray. The microstructure, roughness, and constituents of W-SiC-C/C composite materials were investigated using a scanning electron microscope, energy dispersive X-ray spectroscope, X-ray diffractometer, and atomic force microscope. The tungsten coating structure that may prevent crack propagation essentially consisted of a stacked lamellar columnar microstructure and particle cluster microstructures. The interfaces between the tungsten and SiC coating and between the SiC coating and the C/C were clear. The SiC interlayer acts as a barrier for carbon and tungsten diffusion. The thermal conductivity of the system was calculated by the mixture rule, which was 47.33 to 82.35 W/(m·K). The thermal expansion coefficient of W-SiC-C/C was negative at room temperature and up to 1.5 × 10⁻⁶/K for elevated temperature.

Keywords:

• Tungsten coating
• SiC interlayer
• carbon/carbon
• thermal properties
• inert plasma spray

Acknowledgment

This work was supported by the National Natural Science Foundation of China (numbers 51671150 and 51571135).

Disclosure Statement

No potential conflict of interest was reported by the author(s).