Molecular Dynamics Insight into Softening Mechanism of Zirconia and Prediction of Removal Depth in Magnetic Abrasive Finishing

Abstract Zirconia ceramic is widely used in dentistry and precision industries owing to its high hardness and fracture toughness. Nevertheless, its high hardness and toughness cause severe tool wear, and microcracks tend to form on the machined surface during conventional mechanical processing. This paper proposes a NaOH-PVP-deionized water composite system to realize green chemical softening of zirconia at room temperature and atmospheric pressure. Molecular dynamics simulations reveal that OH– forms strong chemical bonds with surface Zr atoms, thereby inducing surface hydroxylation and increasing the diffusion coefficient of Zr atoms. Adsorbed PVP molecules further regulate the softening process and transform the material from a rigid to a softened state. Simulations verify that such softening is essentially a corrosion reaction and predict the corrosion depth and corrosion rate within 60 min. Experiments combining chemical softening and magnetic abrasive finishing (MAF) show that the surface roughness of zirconia specimens decreases from Ra 0.302 to 0.057, and the material removal rate ranges from 2.29 × 10–3 μm/s to 2.93 × 10–3 μm/s. The average error between simulated and measured removal depths is only 17.02%. This composite system enables effective surface softening of zirconia. The simulation can reproduce the experimental trend, providing feasible theoretical support and a technical route for high-efficiency, low-damage precision machining of zirconia.