Characterization of nickel (II) oxide nanoparticles synthesized by chemical precipitation technique for corrosion inhibition applications

Abstract A novel approach for synthesizing nickel (II) oxide (NiO) nanoparticles was developed by chemically precipitating nickel (II) chloride (NiCl 2 ) derived from dissolving pure solid nickel in concentrated hydrochloric acid. The synthesized nano-particles were then characterized and evaluated as a corrosion inhibitor for mild steel. Structural, morphological, and thermal properties were analyzed using XRD, FTIR, TEM, SEM-EDX, TGA/DTA, and DSC techniques. The nanoparticles exhibited a highly crystalline structure with an average crystallite size of 23.03 nm, which was consistent with TEM analysis showing individual particle sizes between 10.02 and 28.50 nm. Thermal analysis revealed a significant decomposition event at 519.4 °C, indicating high thermal stability. The corrosion inhibition potential was assessed on mild steel specimens coated with an epoxy resin containing 1 wt. % NiO nanoparticles and immersed in a 3.5 wt. % NaCl solution. The results demonstrated a substantial decrease in corrosion rate with the addition of NiO. The epoxy-1 wt% NiO nanocomposite coating provided the highest inhibition efficiency compared to the sample coated with only epoxy resin and the uncoated sample reaching 91.0 % and required a higher activation energy to initiate corrosion compared to both uncoated and neat epoxy-coated samples. This study confirms the successful synthesis of stable, crystalline NiO nanoparticles via a novel chemical precipitation method and establishes their superior performance as an active component in epoxy coatings for robust corrosion protection of mild steel.