The aim of the present work was to study the corrosion inhibition of mild steel using a ternary formulation. This new ternary inhibitor formulation, viz., Polyacrylic acid (PAA), with nickel ions and Potassium Sodium Tartrate (SPT) was used to protect mild steel from corrosion in a low-chloride environment. The weight loss studies showed that 93% inhibition efficiency was achieved with the ternary system consisting of 50 ppm Ni²⁺ ions, 200 ppm PAA, and 600 ppm SPT. Electrochemical methods (potentiostatic polarization and electrochemical impedance studies) and surface characterization techniques Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to ascertain the nature of the protective film and for explaining the mechanistic aspects of corrosion inhibition.