Rheological properties of magnetic field-assisted thickening fluid and high-efficiency spherical polishing of ZrO2 ceramics

Shear thickening polishing technology using non-Newtonian polishing fluids is a low-cost, low-damage polishing method for the ultra-precision machining of complex curved surfaces. However, the low polishing efficiency and poorly controlled viscosity of traditional shear thickening polishing fluids significantly limit their practical applications. In this study, a novel weak magnetic field-assisted shear thickening polishing fluid (WMFA-STPF) containing carbonyl iron particles, which utilized a weak magnetorheological effect to promote the shear thickening process, was developed, and its rheological characteristics were investigated. The obtained results revealed that WMFA-STPF exhibited good fluidity at low shear rates and enhanced thickening characteristics in the working shear rate range. To verify the high efficiency, high quality, and uniform polishing ability of WMFA-STP technology applied to the spherical surface of a zirconia ceramic workpiece, contrast polishing experiments were performed. After 75 min of polishing, the surface damage was effectively mitigated; the surface quality and uniformity were significantly improved; and the material removal rate increased by 156% up to 7.82 mu m/h. Hence, the WMFA-STP method can be successfully utilized for the high-efficiency high-quality polishing of hard and brittle ceramics.