Research on the rheological characteristic of magnetorheological shear thickening fluid for polishing process

A magnetorheological shear thickening fluid (MSTF) is prepared through adding carbonyl iron particles and Al2O3 abrasives into the traditional shear thickening fluid (STF) to improve low shear stress characteristic of STF in this work. To select the optimal sample as base fluid for MSTF, a series of STFs was pre-prepared and its rheological characteristics were further tested, which contained different concentrations of starch polymer and abrasive. Furthermore, different character parameters of MSTFs, such as magnetic field intensity and carbonyl iron particle’s concentration, were experimentally tested to explore its rheological characteristics. Then, the magnetorheological effect on shear thickening formation of MSTFs was furtherly discussed. Experimental results show that with the same base fluid the viscosity and the shear stress of MSTFs are both higher than of STFs under the action of magnetic field. Moreover, the MSTF exhibits a good shear thickening effect under the weak magnetic field intensity and at low level of iron particle concentration, because the existence of hydrogen bonds and magnetic particle chains makes the shear thickening effect of MSTF enhanced by particle clusters. The results indicate that the MSTFs as polishing fluid contribute to develop a higher efficiency polishing method in the future.