A Study of Influence of Anion on Microstructural Development and Sintering of Nanosized Alumina

Abstract

Nanosized alumina has been synthesized by employing two aluminum salts with monovalent anions that is aluminum nitrate and aluminum chloride as precursors under identical reaction conditions by homogeneous precipitation method. In both the cases, gelation of aluminum hydroxide occurred in comparable pH regime and produced alumina nanoparticles with comparable average particle size; however their sintering behavior and microstructure of finished products was not comparable. Nanopowders obtained from aluminum nitrate were highly consolidable and sinterable producing reasonable final densities conversely to nanopowders obtained from aluminum chloride which were less consolidable and sinterable, besides the final products showed microstructural flaws including cracks and outgrowths due to inherent passive thermal transformations of nanopowders and unavoidable interferences. DSC/TG, TDA, SEM-EDS, XRD techniques were employed to characterize the nanopowders and dense products.

Keywords: Nanoalumina precursors, aluminum chloride, aluminum nitrate, sintering