Effect of CTAB Addition on Improvement of Properties of Al2O3(w)–Al2O3(n)–ZrO2(n) (3mole% Yttria Stabilized Tetragonal Zirconia) Nanocomposite

Abstract

Vickers hardness and density of composites, consisting of 20wt% Al 2 O 3 (in form of nanoparticles and/or whiskers) as reinforcement and 3-mole% yttria stabilized tetragonal zirconia (abridged as TZ-3Y) as matrix, were significantly enhanced by addition of 1wt% CTAB. The Al 2 O 3 whiskers were formed in situ from ammonium aluminum carbonate hydroxide (AACH) whiskers during sintering at 1450º C. An increase in hardness was also observed by increasing the fraction of alumina whiskers up to a critical value (5wt% Al 2 O 3(w)-15wt%Al 2 O 3(n)) followed by a decrease in hardness by further increase in whisker fraction. The maximum hardness (i.e., at critical composition) was 14.29GPa and 13.65GPa, for samples with and without 1wt% CTAB, respectively. These hardness values are higher than already reported value of 12.4GPa for 2.5wt% Al 2 O 3(w)-17.5wt% Al 2 O 3(n) by Nevarez-Rascon et al. The improvement in hardness was attributed to the use of whiskers with comparatively larger diameter as well as improved dispersion of whiskers due to CTAB. At higher whisker fractions, a decrease in hardness could be related with agglomeration of whiskers.