Dependence of viscosity of suspensions of ceramic nanopowders in ethyl alcohol on concentration and temperature

This work presents results of measurements of viscosity of suspensions including yttrium oxide (Y(2)O(3)), yttrium aluminum garnet (Y(3)Al(5)O(12)) and magnesium aluminum spinel (MgAl(2)O(4)) nanopowders in ethanol. Nanoparticles used in our research were either commercially available (Baikowski) or nanopowders newly developed in the Institute of Ceramics and Building Materials in Warsaw, Poland. The study was conducted in a wide range of shear rates (0.01 to 2,000 s(−1)) and temperature interval from -15°C to 20°C. A Haake Mars 2 rheometer from Thermo Fisher, Germany, was used in the Biophysics Laboratory at Rzeszów University of Technology. Most of the samples show a non-Newtonian behaviour. It was confirmed with a Rheo-NMR system from Bruker that 10% by weight of Y(2)O(3) suspension is a non-Newtonian fluid. In this work, we also report an unexpected behaviour of the viscosity of some samples (Y(2)O(3) and Y(3)Al(5)O(12)) due to sedimentation effect.