Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8026281 | Surface and Coatings Technology | 2015 | 6 Pages |
Abstract
Monetite (CaHPO4) coatings were deposited on H2O2-treated carbon/carbon (C/C) composites by induction heating deposition (IHD) at electromagnetic frequencies ranging from 289Â kHz to 438Â kHz. The composition, microstructure and bonding strength of the monetite coatings on the C/C composites were investigated by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and large load scratch tester (LLST). The effects of the electromagnetic frequencies on the deposition kinetics of the monetite coatings on the C/C were also analyzed. The results showed that when the electromagnetic heating frequencies were 289Â kHz, 319Â kHz and 381Â kHz, the monetite coatings presented similar compact morphologies, and critical loads of 38Â N, 64Â N and 25Â N. The deposition processes of these monetite coatings were controlled by a surface reaction and their apparent activation energies were 20.26, 22.17, and 31.07Â kJ/mol at 289, 319 and 381Â kHz. But at 438Â kHz, it showed a loose morphology and could be very easily scratched off, presenting a critical load of 0Â N. The changes in the microstructure and adhesiveness of the monetite coatings were discussed at the different electromagnetic frequencies.
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Authors
Xiong Xin-bo, Cheng Miao-miao, Xu Feng, Ji-zhao Zou, Zeng Xie-rong,