Environmentally friendly chemical–magnetorheological finishing method for Ti–6Al–4V biological material based on Fe3O4@SiO2, oxaloacetate acid and H2O2

Titanium alloy is extensively utilised in various advanced equipment across multiple industries, especially in biological implantable devices. The surface machining of such devices is required to provide a finished surface with high precision and gloss. This study presents an established ecofriendly slurry for a hybrid polishing process utilising a highly efficient chemical and magnetorheological fluid (C-MRF) to obtain ultraprecise surface quality. This slurry incorporated Fe₃O₄@SiO₂ abrasive particles, oxaloacetate acid (C₄H₆O₅), deionised water and hydrogen peroxide (H₂O₂) as an oxidiser. Ti–6Al–4V workpieces polished with C-MRF based on Fe₃O₄@SiO₂ abrasives and polishing performance were used to investigate the influence of the oxidising agent H₂O₂ and oxaloacetate acid (monitored with a pH indicator) on the surface finish of Ti–6Al–4V biomaterial. In contrast to the traditional mechanical and chemical polishing methods for titanium alloys that often include strong bases and acids along with chemicals that endanger the environment and humans, the proposed polishing process based on the newly developed ecofriendly magnetic composite leveraged the advantages of magnetorheological fluid with chemical reactions to create an ultra smooth surface. Experiments were performed to investigate the influence of different polishing durations and factors on the quality of polished surfaces, thereby optimising technological parameters, reducing time and improving surface quality. Various technological parameters were evaluated through single-factor and orthogonal experiments to assess their distinct effects on surface quality and material removal capability. This work proposed an environmentally friendly C-MRF method for finishing Ti–6Al–4V biomaterial with high efficiency and industrial applicability.