Magnetorheological (MR) Polishing of Alumina-Reinforced Zirconia Ceramics Using Diamond Abrasives for Dental Application

In this study, ultraprecise polishing of alumina reinforced zirconia ceramics using magneto rheological (MR) fluids and diamond abrasives was investigated. First, alumina-reinforced zirconia composites, containing 0 to 30 vol% alumina, were fabricated by cold isostatic pressing at 150 MPa. The green compacts were then sintered at 1,550°C for 2 h in air. Mechanical properties and microstructures of the composites were observed. Second, a series of MR polishing experiments were performed for composites containing 20 vol% of alumina under various polishing conditions. MR polished surfaces were observed using a scanning electron microscope (SEM) and surface profiler to investigate the variation of the surface integrity. A very fine surface roughness of Ra = 1.960 nm was obtained after 60 minutes of MR polishing using diamond abrasives.