The structural and mechanical properties of the nanostructured alpha-alumina (α-Al2O3) compact powders, formed by calcination of aluminum hydroxide (Al2(OH)6) gibbsite at different temperatures (100–1100 °C), followed by uniaxial pressing and subsequently hot isostatically pressed (HIP), were investigated using X-ray diffraction, scanning electron microscopy (SEM), and type ball-on-disk oscillating tribometer. X-ray diffraction analysis indicates that the transformation sequence involves the formation of κ-Al2O3 as an intermediate phase between χ- and α-Al2O3. The crystallite size of calcined alumina (α-Al2O3) was as small as 8 nm after calcination at 1100 °C. The sliding friction and wear rate were lower in the nanocrystalline samples calcined at 1100 °C at same applied load (3, 6, or 10 N). The enhanced friction and wear resistance were endorsed to have fin microstructure similar to the sample calcined at 1100 °C.
Journal of the Australian Ceramic Society – Springer Journals
Published: Mar 27, 2019