Sintering studies of nanophase ceramic oxides using small angle scattering

The microstructure evolution during sintering of nanophase ceramics has been followed using small-angle neutron and X-ray scattering. These techniques enable material microstructure parameters and surface areas to be measured nondestructively, and have been applied to study the effects of different sintering temperatures, pressures and additives. Depending on the sintered density, the scattering data from nanophase materials exhibit Pored scattering associated with the high surface area, scattering from the nanometer-size grains and pores, and interparticle interference scattering. By using samples of sufficient size and uniformity to permit absolute calibration of the scattering data, it has been possible to develop a fully quantitative microstructure model. Studies of nanophase yttria (powder, prepared by Nanophase Technologies Corporation, Burr Ridge, IL) and zirconia (powder, prepared at Rutgers University, Piscataway, NJ) are discussed, and it is shown how small-angle scattering, in conjunction with density measurements, electron microscopy and X-ray diffraction, provides a unique probe of the statistically representative microstructures present in these novel materials.