Title: A detailed study on the enhanced anti-corrosion properties of nano silicon dioxide additive influencing calcium modified zinc phosphate coating on mild steel

Authors: Ruby Thomas; J. John Alphin; A. Unock; M.J. Umapathy; B. Vigneshwaran

Addresses: Department of Chemistry, Loyola College Nungambakkam, Chennai, Tamil Nadu, India ' Department of Chemistry, Loyola College Nungambakkam, Chennai, Tamil Nadu, India ' Department of Chemistry, Loyola College Nungambakkam, Chennai, Tamil Nadu, India ' Department of Chemistry, CEG Guindy Campus, Anna University, Chennai, Tamil Nadu, India ' Centre for Nanoscience and Nanotechnology, International Research Centre, Sathyabama Institute of Science and Technology, Chennai, Tamil Nadu, India

Abstract: The influence of nano silicon dioxide additive on calcium modified zinc phosphated mild steel sample is researched in this paper. This study shows that the environment friendly nano additive provides a high porous, fine-grained and compact phosphate sealing by facilitating strong adsorption to the successive protective covering of mild steel. The formed coatings were characterised by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), atomic force microscopy (AFM) and atomic absorption spectroscopy (AAS). The thermal stabilities of the coatings were analysed by thermo gravimetric analysis (TGA). The coating quality on the mild steel surface was examined by coating weight, porosity and adhesion tests. The corrosion studies were done using salt spray test and electrochemical impedance spectroscopy. The good dispersibility of the additive was observed on the coating with increased safety from erosion. The lower i_corr value of 2.6477 × 10^-5 A/cm² for CaZnPS when compared to 8.212 × 10^-5 A/cm² for CaZnP indicated that the nano additive has more shielding effect. The results reveal that the barrier and corrosion inhibition tendencies were increased with the addition of nano particles to the calcium modified zinc phosphated mild steel.

Keywords: nano silicon dioxide; mild steel; calcium; zinc phosphate; coating; surface; corrosion.

DOI: 10.1504/IJSURFSE.2022.125436

International Journal of Surface Science and Engineering, 2022 Vol.16 No.3, pp.207 - 225

Received: 06 Dec 2021
Accepted: 03 Jan 2022
Published online: 09 Sep 2022 *

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