Effects of sample bias on adhesion of magnetron sputtered Cr coatings on SiC

JOURNAL OF NUCLEAR MATERIALS

卷:556

Article

Mouche, P. A.¹  Evans, A.²  Zhong, W.¹  Koyanagi, T.¹  Katoh, Y.¹ 

[1] Oak Ridge Natl Lab, Mat Sci & Technol Div, Oak Ridge, TN 37830 USA

[2] Manchester Metropolitan Univ, Surface Engn Grp, Manchester, Lancs, England

关键词: Adhesion;    DC magnetron sputtering;    Ceramic nuclear fuel cladding;    SiC;    Residual stress;    Texture;   

DOI  :  10.1016/j.jnucmat.2021.153251

来源: Elsevier

【 摘 要 】

Swelling of SiC at 300 degrees C due to in-service neutron irradiation causes tensile residual stresses in coatings which are expected to adversely affect the performance of coated SiC composite fuel cladding for light water reactors. Matching the coating swelling with the substrate, a solution common for thermal expansion, is not practical in the case of neutron irradiation. Biasing samples during magnetron sputtering deposition induces compressive residual stress which may counteract this. In this study, chromium coatings were deposited on SiC by DC magnetron sputtering with no external heating at bias voltages of -50V, -75V, and -100V. The effects of the bias voltage on morphology, residual stress, microstrain, texture, and adhesion are shown. The low deposition temperature resulted in the coating microstructure evolution following an energetic particle bombardment dominated trend. At the two lower bias voltages knock-on implantation dominated increasing the residual stress and microstrain while at the highest bias voltage, thermal spike migration allowed for defect relaxation. When the knock-on induced compressive residual stress exceeded 0.8 GPa microcrack formation in the SiC substrate decreased coating adhesion. While no microcracks formed at the lowest bias voltage, insufficient atomic mobility during coating growth lead to voids forming in the coating. A balance is needed to form void-free coatings that have high compressive residual stress. (C) 2021 Elsevier B.V. All rights reserved.

【 授权许可】

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