SINTERING CHARACTERISTICS OF NANOCRYSTALLINE TIO2

The microstructural development of compacted nanocrystalline Ti02 powder was studied as a function of sintering temperature up to 1000 °C. Grain growth was monitored using x-ray diffraction and scanning electron microscopy. The specific surface area and total porosity were determined quantitatively using the nitrogen adsorption BET. The density was measured by gravimetry using Archimedes principle. The green body density of compacted n-Ti02 with average grain size of 14 nm is as high as 75% of theoretical bulk density. Low temperature surface diffusion leads to the disappearance of small pores, while noticeable densification commences at 600 °C and reaches near theoretical values at 900 °C. Grain growth also begins at 600 °C, accelerating rapidly by 1000 °C. Hot isostatic pressing is observed to enhance densification while suppressing grain growth. © 1990, Materials Research Society. All rights reserved.