Synergistic behaviour of ultrasonic vibration and mixed electrolytes on machined surface morphology in ECG of Hastelloy C276

The surface morphology and topography are functionally important; hence, the present study explores the synergistic effect of ultrasonic vibration (UV) and mixed electrolytes on enhancing the surface morphology of Hastelloy C276 during Electrochemical Grinding (ECG). Two sets of experiments were performed: conventional ECG and UVECG using mixed electrolyte solutions of NaNO3 and NaCl at various proportions. Surface parameters and topography were measured by a 3D profilometer and SEM. Results indicated that NaCl yielded relatively lower surface roughness with minor microcracks, whereas NaNO3 provided smoother surfaces. The mixed electrolytes (2:1 ratio) produced a superior finish, improved surface quality by around 39%, reduced pitting, and enabled uniform material removal with UV. Further, the material ratio curve confirms that the mixed electrolyte has lower peak and valley void volumes and reduced surface irregularities, with lower Mr2% in UVECG. These findings demonstrate that integrating UV-assistance with optimized mixed electrolytes significantly improves the surface quality of Hastelloy C276.