Interaction Between Plasma and Tungsten Carbide Thin Films Coated on Stainless Steel as Tokamak Reactor First Wall

Azadeh Jafari1*, Vahid Fayaz1, Sakineh Meshkani2, and S. Ali Asghar Terohid1

1Department of Physics, Hamedan Branch, Islamic Azad University, Hamedan, Iran
2Plasma Physics Research Center, Science and Research Branch,
Islamic Azad University, Tehran, Iran

Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.


The physical properties of tungsten carbide (WC) thin film as a first wall material when it is exposed to the plasma of tokamak was studied in this research. In this regard, WC thin film was formed on grade 316L stainless steel – via the hot filament chemical vapor deposition method – to the sample installed on Iran tokamak 1 chamber and exposed to 300 shots of hydrogen plasma for a total duration of 11 s. For investigation of hydrogen plasma effects on morphology, crystalline structure properties, and roughness of the sample, X-ray diffraction (XRD), scanning electron microscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and Raman spectroscopy analysis was performed. The experimental setup described and micrographs of the surfaces are shown. XRD analysis of WC thin film coated on stainless steel before and after plasma shots shows the changes in crystal structure. Based on the scanning electron microscopy images, it can be concluded that plasma exposure has created some cracks, holes, and lines. Also, the roughness of the sample after plasma shots decreased and it was observed that the thickness of WC thin film coated on stainless steel is reduced after plasma shots were introduced. Moreover, the weight loss of the uncoated sample was higher in comparison to the coated one. Finally, WC coating on the first wall of fusion device looks promising, but several open questions still remain to be solved.


Key issues to address in modern nuclear research include the choice of first wall materials and understanding the effects of plasma materials on a fusion device and how they interact. Particularly, plasma energy confinement time is strongly dependent on the first wall material selection and on how the wall interacts with edge plasmas (Hino & Yamashina 1996; Kirnev et al. 2001; Buzinskij et al. 1999). Recently, the use of coatings on material surfaces to improve their quality and reduce their damage according to their application has been considered (Xu et al. 2006; Niknahad & Mannari 2016; Taha et al. 2010; Habibi et al. 2015). . . . read more


BUZINSKIJ OI, BEGRAMBEKOV LB. 1999. Features and advantages of boron carbide as a protective coating of the tokamak first wall. Fusion Eng. & Des. 45: 193–199.
CHEN JM, LIU X, WU JH, SHEN LR, XU ZJ, ZHANG NM, LIU Y, PAN CH, WANG XS, XIE DH, XIAN XB, ZHANG PC, WANG ZH, WANG L, LI ZN, LI Z, MU XC, WAN ZJ, TANG YM. 2008. ITER first wall fabrication technology in China. In: Proceedings of 22nd IAEA FEC, Geneva, Switzerland, 13–18 Oct 2008.
GHORANNEVISS M, HOGABRI A, KUHN S. 2003. MHD activity at low q(a) in Iran Tokamak 1 (IR-T1). J. Nucl. Fusion 43: 210–216.
HABIBI M, ESLAMIAN M, SOLTANI-KORDSHULI F, ZABIHI F. 2015. Controlled wetting/dewetting through substrate vibration-assisted spray coating (SVASC). Journal of Coatings Technology and Research 13(2): 211–225.
HINO T, YAMASHINA T. 1996. Development of plasma facing components and plasma surface interaction studies in Japan. Physica Scripta 64: 48–52.
JAFARI A, GHORANNEVISS M, MESHKANI S. 2016a. The Study of Plasma-TiN Interaction in Tokamak. Journal of Alloys and Compounds 656: 318–325.
JAFARI A, ALIPOUR R, GHORANNEVISS M, RAMEZANI AH. 2016b. Specialized Study on Morphological Features of Tungsten Carbide Thin Film Synthesis by HFCVD. Journal of Inorganic and Organometallic Polymers and Materials 26: 384–393.
JAFARI A, MESHKANI S, GHORANNEVISS M. 2016c. The Study of Surface Properties of Tokamak First Wall Using TiN Coated on Stainless Steel. Journal of Fusion Energy. 35: 235–239.
KIRNEV GS, BUDAEV VP, GRASHIN SA, KHIMCHENKO LN, SARYTCHEV DV. 2001. Comparison of plasma turbulence in the low- and high-field Scrape-Off Layers in the T-10 tokamak. J. Nucl. Fusion 41: 585–596.
MANOJ B, KUNJOMANA AG. 2012. Study of Stacking Structure of Amorphous Carbon by X-Ray Diffraction Technique. Int. J. Electrochem. Sci. 7: 3127–34.
MCGUIRE GE, SCHWEITZER GK, CARLSON TA. 1973. Core electron binding energies in some Group IIIA, VB, and VIB compounds. Inorg. Chem. 12(10): 2450–53.
MEROLA M, LOESSER D, RAFFRAY R. 2010. Power handling in ITER: Divertor and blanket design and R&D. In: Proceedings of 23rd IAEA Fusion Energy Conference, Daejon, Republic of Korea, 11–16 Oct 2010.
NERZ J, KUSHNER B, ROTOLICO A. 1992. Microstructural evaluation of tungsten carbide-cobalt coatings. Journal of Thermal Spray Technology 1: 147–152.
NIKNAHAD M, MANNARI V. 2016. Corrosion protection of aluminum alloy substrate with nano-silica reinforced organic–inorganic hybrid coatings. Journal of Coatings Technology and Research 13: 1035–46.
SICKAFOOSE SM, SMITH AW, MORSE MD. 2002. Optical spectroscopy of tungsten carbide (WC). J. Chem. Phys. 116: 993–999.
TAHA M, EL-MAHALLAWY N, HAMMOUDA R, NASSEF S. 2010. PVD coating of Mg-AZ31 by thin layer of Al and Al-Si. Journal of Coatings Technology and Research 7(6): 793–800.
WAGNER CD, DAVIS LER, MOULDER JF, RIGGS WM. 1979. Handbook of X-ray Photoelectron Spectroscopy. Perkin-Elmer: Minnesota, USA.
XU ZY, LIU X, CHEN JM, WANG MX, SONG JR, ZHAI GT, LI CX. 2006. A New Type of Multielements-Doped, Carbon-based Materials Characterized by High Thermoconductivity, Low Chemical Sputtering, Low RES Yield and Exposure to Plasma. Plasma Science and Technology 4: 1311–17.
ZHONG Y, SHAW L. 2011. A study on the synthesis of nanostructured WC-10 wt% Co particles from WO and graphite. Journal of Materials Science 46: 6323–6331.