Boehmite powder has been prepared by hydrolysing aluminium iso-propoxide and peptising with nitric acid. This amorphous boehmite undergoes a series of phase transitions (γ-AlOOH → γ-Al2O3 → δ-Al2O3 → α-Al2O3 ) on heating. Thermal analysis and phase determination using XRD and IR spectra of powder calcined at different temperatures confirmed the phase transitions. The effects of dry and wet milling on powder particle size, sinterability, and microstructure of sintered bodies have been studied. Compacts of wet milled powder calcined at 1000°C attained 98% of theoretical density at 1600°C.
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References
1.
DORREE. and HUBNERH.: in ‘Alumina: processing, properties, and applications’; 1984, Berlin, Springer.
2.
WATCHMANJ. B. and HABERR. A.: in ‘Alumina chemicals: science and technology handbook’, (ed. HartL. D. et al), 319–325; 1990, Westerville, OH, American Ceramic Society.
JAWORSKA-GALASZ., JANIAKS., MISTAW., WRZYSZCZJ., and ZAWADZKIM.: J. Mater. Sci., 1993, 28, 2075–2078.
8.
HENCHL. L. and WESTJ. K.: Chem. Rev., 1990, 90, 33–72.
9.
KUMAGAIM. and MESSINGG. L.: J. Am. Ceram. Soc., 1985, 68, 500–505.
10.
ZAKHARCHENYAR. I. and VASILEVSKAYAT. N.: J. Mater. Sci., 1994, 29, 2806–2812.
11.
SARASWATIV., RAOG. V. N., and RAMA RAOG. V.: J. Mater. Sci., 1987, 22, 2529–2534.
12.
DWIVEDIR. K. and GOWDAG.: J. Mater. Sci. Lett., 1985, 4, 331–334.
13.
‘Powder diffraction fine inorganic phase alphabetical index (chemical and mineral names)’, JCPDS International Centre for Diffraction Data, Newton Square, PA, 1985.
14.
RAMA RAOG. V., VENKATESANS., and SARASWATIV.: J. Non-Cryst. Solids, 1989, 111, 103–112.
15.
OGIHARAT., NAKAJIMAH., YANAGAWAT., OGATAN., and YOSHIDAK.: J. Am. Ceram. Soc., 1991, 74, 2263–2269.
