SINTERING CHARACTERISTICS OF NANOCRYSTALLINE TIO2 - A STUDY COMBINING SMALL-ANGLE NEUTRON-SCATTERING AND NITROGEN ABSORPTION-BET

Small angle neutron scattering (SANS) was employed to characterize the pore structure of nanophase TiO2 ceramic materials compacted at different temperatures. Nanophase samples, produced by inert gas condensation, were compacted at 25, 290, 413, and 550-degrees-C using a pressure of almost-equal-to 1 GPa. The pore size distribution of the sample compacted at room temperature was very broad, with sizes ranging from almost-equal-to 3-30 nm and pores comprising 38% of the sample volume. Compaction at 290 and 413-degrees-C reduced the pore volume to 25% and 20%, respectively, by eliminating pores at both the small and large ends of the distribution. Compaction at 550-degrees-C resulted in pore volume that was less than 8%. Complications in the SANS analysis arising from the scattering from grain boundaries are discussed. The results from SANS are compared with those derived from nitrogen absorption, BET, measurements.