Characterization and properties of tungsten carbide coatings fabricated by SPS technique

• Published in: Journal of nuclear materials Vol. 433; no. 1-3; pp. 449 - 454
• Main Authors: Jiang, Y., Yang, J.F., Zhuang, Z., Liu, R., Zhou, Y., P. Wang, X., Fang, Q.F.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2013; Elsevier
• Subjects: Applied sciences; Coatings; Controled nuclear fusion plants; Corrosion resistance; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Hardness; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels; Protective coatings; Spark plasma sintering; Thermal conductivity; Tungsten; Tungsten carbide; Scanning electron microscopy; Plasma; Hardness test; X ray diffraction; Nitric acid; Nuclear reactor; Corrosion resistance; Sintering; Tungsten; Graphite; Thermal conductivity; Protective coatings; Carbides; Crystalline structure
• DOI: 10.1016/j.jnucmat.2012.10.020
• ISSN: 0022-3115

Tungsten carbide coatings were fabricated on tungsten substrates with spark plasma sintering method by covering a layer of graphite powders on the substrates. Composition, crystalline structure, hardness, thermal conductivity and corrosion resistance of the coatings were evaluated by scanning electron microscopy, X-ray diffraction, Vickers hardness test, electrochemical impedance spectroscopy and dipping experiment. It was found that the W–C coated samples exhibit three-layer structure containing three different phases, which from the surface to the interior are hexagonal WC, hexagonal W2C and body center cubic W(C), respectively. Thickness of the total W–C coatings is about 20μm, and closely dependent upon the holding time and sintering temperature; average hardness of the coatings was 2125 HV; thermal conductivity of both uncoated and coated samples is similar and decreases from 180 to 130Wm−1K−1 in the temperature range of 27–500°C. Furthermore, W–C coated samples have better corrosion resistance than that of uncoated samples in 3.5% NaCl solution or 10% nitric acid solution at room temperature.