Corrosion resistance of functionalized carbon nanotubes enhanced epoxy coatings on sintered NdFeB magnets

• Published in: JCT research Vol. 19; no. 5; pp. 1317 - 1329
• Main Authors: Yang, Hongyi, Duan, Liangsong, Zhang, Pengjie, Xu, Guangqing, Cui, Jiewu, Lv, Jun, Sun, Wei, Li, Bingshan, Wang, Dongmei, Wu, Yucheng
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2022; Springer Nature B.V
• Subjects: Cathodic coating (process); Chemistry and Materials Science; Corrosion and Coatings; Corrosion prevention; Corrosion resistance; Corrosion tests; Electrophoretic deposition; Epoxy coatings; Epoxy resins; Industrial Chemistry/Chemical Engineering; Materials Science; Multi wall carbon nanotubes; Permanent magnets; Polymer Sciences; Sintering; Sodium chloride; Surfaces and Interfaces; Tannic acid; Thin Films; Tribology; Epoxy coatings; Corrosion resistance; Carbon nanotubes; Tannic acid functionalization; NdFeB magnets
• ISSN: 1547-0091; 1935-3804; 2168-8028
• DOI: 10.1007/s11998-022-00641-x

In this work, tannic acid (TA) was employed to modify the surface of multiwall carbon nanotubes (CNTs) to form TCNTs hybrids via noncovalent functionalization to enhance its dispersibility in water. Then, the TCNTs enhanced epoxy coatings were applied on sintered NdFeB magnets by cathodic electrophoretic deposition method for corrosion test. The corrosion resistance of prepared specimens was assessed by electrochemical experiments. The results show that TCNTs hybrids present a more homogeneous distribution in epoxy resin than pristine CNTs and could obviously promote anticorrosion properties of prepared specimens. Within 36-day soaking in 3.5 wt.% NaCl solution, the specimens maintain a high value of | Z | 0.01Hz (10 8  Ω cm 2 ) when the concentration of TCNTs is 2 g/L. When immersed in 3.5 wt.% NaCl solution for 40 days, the E corr of specimens shifts to − 0.207 V and J corr is about 5.281 × 10 −11  A cm −2 , which demonstrates superior corrosion resistance.