基于Halbach阵列的磁场辅助剪切增稠抛光氧化锆陶瓷的实验研究OA

Zirconia(ZrO2)ceramics are extensively utilized in the aerospace,automotive,and biomedical sectors due to their exceptional mechanical properties and favorable biocompatibility.However,the inherent high hardness and brittleness of ZrO2 pose significant challenges for conventional polishing tools in achieving effective surface removal of workpieces.To achieve high-efficiency,low-damage,and low-cost precision polishing of zirconia ceramics,and to further extend the magnetic field-assisted shear thickening polishing process,this study,based on magnetic-field-assisted shear thickening polishing technology,incorporates a Halbach-array magnetic field and employs magnetic field arrangement control methods.It proposes a Halbach-array magnetic-field-assisted shear thickening polishing method,achieving high-efficiency,low-damage,and low-cost precision polishing of ZrO2 ceramics. Firstly,the magnetic-field rheological response characteristics of magnetic polishing slurries are investigated.Magnetic-field rheological tests are conducted on magnetic shear thickening slurries prepared with carbonyl iron powder at different mass fractions.Based on evaluation criteria including higher peak viscosity results and a broader stable thickening range,a magnetic shear thickening polishing slurry containing 4%iron carbonyl powder(at a magnetic induction of 150 mT)is selected as the optimal formulation.This formulation demonstrates the most pronounced synergistic enhancement effect between magnetorheological and shear thickening properties.Secondly,the magnetic field distribution of the Halbach array is analyzed through simulation and experimental methodology.By simulating the dimensions and arrangement of the magnets,a Halbach array magnetic field is designed comprising 11 magnets,characterized by a large and uniformly distributed magnetic flux excitation area.Based on these results,a Halbach array is fabricated and its magnetic flux density is measured.The measurements indicate an average magnetic flux density of 150.2 mT,distributed relatively uniformly across the central region,providing a reliable magnetic field source for subsequent polishing experiments.Finally,Halbach-array magnetic-field-assisted shear thickening polishing experiments are conducted on ZrO2.Through systematic design of experimental process parameters,the influence patterns on the surface roughness(Ra)and material removal rate(MRR)of ZrO2 are elucidated.The rotation of the ZrO2 workpiece ensures uniform force distribution across all surface areas,thereby enhancing edge polishing intensity and reducing polishing irregularities.Optimization experiments employing the signal-to-noise ratio method for polishing parameter combinations are conducted to validate their polishing efficacy.The results indicate that under the magnetic field conditions of a Halbach array comprising 11 magnets,increasing the polishing rotational speed enhances fluid velocity,thereby elevating shear rates.This generates a greater number of particle clusters containing abrasive grains,which remove micro-protrusions from the ZrO2 surface.Consequently,both the surface quality of the ZrO2 and the material removal rate are improved.By increasing the polishing angle,the action of the polishing fluid on ZrO2 shifts from shear stress to normal impact,reducing the tangential velocity component and lowering the shear rate,thereby decreasing the material removal rate.Under the conditions of the self-built experimental platform,the optimal polishing process combination is as follows:polishing speed of 80 rpm,polishing angle of 30°,and workpiece rotational speed of 48 r/min.Following 60 minutes of polishing,the surface waviness of the ZrO2 exhibits minimal change,presenting an overall smooth and flat result.The Ra decreases from 601 nm to 11 nm,with the MRR reaching 7.26 μm/h.Compared with the conventional shear thickening method without magnetic field application,the Ra reduction amounts to 85.6%,while the MRR is increased by a factor of 1.33. In summary,the Halbach-array magnetic-field-assisted shear thickening polishing method effectively enhances the surface quality and material removal rate of zirconia ceramics,enabling efficient,low-damage,and low-cost processing.