Effects of TiO2 nanoparticles on the adhesion and anticorrosion properties of the graphene-based composite coating on mild steel using electrochemical impedance spectroscopy approach

In this study, TiO₂ nanoparticles in varying concentrations of 0.5, 1, 2, and 3 wt.% were added into the acrylic-epoxy polymeric matrix with 90:10 wt.% (90A:10E) ratio incorporated with 1 wt.% graphene, to fabricate graphene/TiO₂ based nanocomposite coating systems. Furthermore, the properties of the graphene/TiO₂ composite coatings were investigated by water contact angle (WCA) measurements, cross-hatch test (CHT), field emission scanning electron microscope (FESEM) and the electrochemical impedance spectroscopy (EIS) studies respectively. The EIS was observed by determining the breakpoint frequencies over a period of 30 days. The results revealed that the TiO₂ nanoparticles were successfully decorated on the graphene surface by chemical bonds, which resulted the graphene/TiO₂ nanocomposite coatings to exhibit better dispersibility within the polymeric matrix. The WCA of the graphene/TiO₂ coating increased along with the ratio of TiO₂ to graphene, achieving the highest CA of 120.85º for 3 wt.% of TiO₂. Excellent dispersion and uniform distribution of the TiO₂ nanoparticles within the polymer matrix were shown up to 2 wt.% of TiO₂ inclusion. Among the coating systems, throughout the immersion time, the graphene/TiO₂ (1:1) coating system exhibited the best dispersibility and high impedance modulus values (|Z|_(0.01 Hz)), exceeding 10^10 Ω cm^2.

Assoc. Prof. Ir. Ts. Dr. Sachin Sharma Ashok Kumar is a material scientist experienced in the development of graphene and graphene oxide nanomaterials incorporated with reinforced composites, supercapattery, batteries, solar cells, fuel cells, hydrogen storage, polymer nanocomposites, corrosion coatings and 3D composites for numerous engineering applications. He received both of his BSc. degree (Hons.) and MSc. (Hons.) in Mechanical Engineering minor in Materials Science from Wichita State University, USA in year 2011 and 2012, respectively. He received his Ph.D. in Advanced Materials Science Engineering in University Malaya in 2023. His current research involves the synthesis of super-hydrophobic graphene-based polymer nanocomposite coatings for corrosion applications. He has published over 60 articles in various high-ranked ISI/WoS- and Scopus-listed journals, participated in 70+ international conferences as a keynote/distinguished/oral speaker and has received several excellence awards at international/national exhibitions pertaining to his research and inventions. He is currently a member and a licensed Professional Engineer registered with the Board of Engineers Malaysia (BEM) and Institution of Engineers Malaysia (IEM) and a Professional Technologist with Malaysia Board of Technologists (MBOT).