Cobalt–phosphorus–titanium oxide nanocomposite coatings: structures, properties, and corrosions studies

• Published in: Journal of materials science. Materials in electronics Vol. 30; no. 22; pp. 19940 - 19947
• Main Authors: He, Zhen, Cao, Di, Qiao, Yanxin, Hayat, Muhammad D., Singh, Harshpreet, Wang, Yuxin
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.11.2019; Springer Nature B.V
• Subjects: Atomic force microscopy; Characterization and Evaluation of Materials; Chemistry and Materials Science; Chromium; Coated electrodes; Cobalt; Corrosion effects; Corrosion resistance; Crystal structure; Electrochemical analysis; Electrochemical impedance spectroscopy; Electrode polarization; Materials Science; Mechanical properties; Microhardness; Microscopy; Microstructure; Nanocomposites; Nanoparticles; Optical and Electronic Materials; Phosphorus; Protective coatings; Surface properties; Titanium dioxide; Titanium oxides; Wear resistance
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-019-02360-3

Chromium coatings are largely restricted in electrical and electronic industries due to the environmental concerns. To address these concerns, a cobalt–phosphorus–titanium oxide (Co–P–TiO 2 ) nanocomposite coating is developed in this study using a nanoparticle-reinforced electrodeposition process. The effects of TiO 2 nanoparticles on the properties of co-deposited Co–P–TiO 2 nanocomposite coatings are investigated. The surface characterisation is carried out by scanning electron microscopy and atomic force microscopy, while the crystal structure is studied using X-ray diffraction. The mechanical properties of nanocomposite coatings including microhardness and wear resistance are also determined. To study the electrochemical behaviour of the coatings, the potentiodynamic polarisation analysis combined with electrochemical impedance spectroscopy is performed. The Co–P–TiO 2 coating at 1 g/L TiO 2 addition displays the best physicochemical performance. Compared to Co–P coating, the mechanical properties of the nanocomposite coating are significantly improved by the strengthening effects of the well-dispersed TiO 2 particles. Excellent corrosion resistance is also achieved for the Co–P–TiO 2 at proper TiO 2 addition due to its smooth and defect-free microstructure. However, it is found that the excessive addition of TiO 2 decreases the coating quality, resulting in an unfavourable microstructure and properties.