Cermet coating, which is a blend of ceramic hardness and metallic toughness, is mostly applied to enhance the wear and corrosion resistance of metals. Detonation gun (D-gun) spraying is one of the most promising thermal spray technologies that would produce a high-quality ceramic coating. Cr3C2-NiCr coating is acceptable because of its superior mechanical characteristics and corrosion characteristic. The effectiveness of D-gun sprayed Cr₃C₂–NiCr coatings was evaluated under aggressive acidic conditions using 1 M H₂SO₄, which serves as a standardized laboratory electrolyte for assessing corrosion resistance relevant to industrial acidic environments, including the key process variables such as spraying distance, which is critically important in the determination of other coating properties such as porosity, adhesion, roughness, and hardness. Duplex stainless steel (DSS) 2205 has been sprayed with Cr3C2-NiCr at three spraying distances; 170 mm, 180 mm and 190 mm in an attempt to conduct the research on the behavior of Cr3C2-NiCr in acid conditions. Electrochemical activity of the coating was evaluated in 1 M H2SO4 solutions at room temperature; by open circuit potential (OCP), electrochemical impedance spectroscopy and potentiodynamic polarisation. Investigation of surface morphology under SEM revealed dense lamellar coatings with porosity decreasing from 2.84% at 170 mm to 1.38% at 190 mm, indicating improved particle melting and coating compactness. The coating deposited at 190 mm exhibited the best electrochemical performance, with lowest corrosion rate (0.113 mmpy), compared with the uncoated substrate (2.60 mmpy). All coated specimens had a homogenous and compact coating structure. The results demonstrate that 190 mm is the optimum spray distance for producing high-integrity Cr₃C₂–NiCr coatings on DSS 2205, providing enhanced corrosion protection for components operating in aggressive acidic industrial environments. This work demonstrates that optimizing the D-gun spray distance significantly influences the microstructural integrity and electrochemical corrosion behaviour of Cr₃C₂–25NiCr coatings on DSS 2205. The established processing–microstructure–performance relationship provides a scientific basis for optimizing D-gun coating parameters to enhance corrosion resistance in aggressive acidic environments.