Surface defects repairing of sprayed Ca-P coating by the microwave-hydrothermal method

Su, Yangyang; Li, Kezhi; Hou, Xianghui; He, Song

Abstract

The increasing interest in decreasing the surface defects of sprayed Ca-P coating deposited on carbon/carbon (C/C) composites to enhance the bonding strength, bioactivity and corrosion resistance of the coating is justified by the growing evidence of its beneficial effect on the bone replacement fields. Microwave-hydrothermal (MH) method detailed in the previous study is successfully used to reduce the above coating defects and the MH mechanism is well studied here. Hence, five different treatment reagents involving calcium and phosphorus solution, sulfuric acid (H2SO4) solution, ammonium hydroxide (NH3·H2O) solution, only Ca2+ solution and deionized water are selected as the precursor solution. The surface, cross-sectional morphologies, phase and composition of the coatings are characterized by the scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), microscopy Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) spectra. Elastic modulus and coating hardness are measured by nanoindentation. Results reveal that the presence of calcium and phosphorus ions, as well as the H2SO4 in the precursor solution during the MH process, have a positive influence on the reduction of sprayed Ca-P coating surface defects. However, the coating treated by other three solutions cannot produce new phases on the basis of sprayed Ca-P coating and the surface defects of it are not decreased. Nevertheless, the elastic modulus and hardness of the coating treated by H2SO4 solution are very weak. MH treated coating by calcium and phosphorus ions in the precursor solution and in NH3·H2O solution, only Ca2+ solution and deionized water own the similar elastic modulus and hardness to that of the sprayed Ca-P coating. To conclude, in the MH process, the surface defects of the sprayed Ca-P coating are only lowered in calcium and phosphorus precursor solution and the coating strength is not dropped, which demonstrates the promoting mechanism of MH process.

Citation

Su, Y., Li, K., Hou, X., & He, S. (2018). Surface defects repairing of sprayed Ca-P coating by the microwave-hydrothermal method. Ceramics International, 44(17), 21699-21709. https://doi.org/10.1016/j.ceramint.2018.08.258

• Journal Article Type: Article
• Acceptance Date: Aug 22, 2018
• Online Publication Date: Aug 23, 2018
• Publication Date: Dec 1, 2018
• Deposit Date: Oct 17, 2018
• Publicly Available Date: Aug 24, 2019
• Journal: Ceramics International
• Print ISSN: 0272-8842
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 44
• Issue: 17
• Pages: 21699-21709
• DOI: https://doi.org/10.1016/j.ceramint.2018.08.258
• Keywords: Process Chemistry and Technology; Materials Chemistry; Electronic, Optical and Magnetic Materials; Surfaces, Coatings and Films; Ceramics and Composites
• Public URL: https://nottingham-repository.worktribe.com/output/1171207
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0272884218323423?via%3Dihub
• Contract Date: Oct 17, 2018