Alpha-Alumina Synthesis

Abstract

The development of ceramic matrix composites (CMCs) is currently of great importance in the field of ballistic protection. For that purpose, alumina, silicon carbide and boron carbide are usually used in civil and military armor. Combination of different materials results in increasingly lighter and tougher composite materials, which replace conventional materials in many applications, including aviation, aerospace, military, naval, and sports industry. The production of nanoparticle powders and nanostructured bodies may find many uses in CMCs. In this study, pseudoboehmite powders was synthesized through the sol-gel method. The main goal of this work was to obtain alpha-alumina from nanosized pseudoboehmite particles, aiming to improve the densification and reduction of sintering temperature of alumina. Both pseudoboehmite and alpha-alumina obtained might be used also as raw material for CMCs. The gel of pseudoboehmite, which was derived from aluminum nitrate and ammonium hydroxide, was calcined, thus originating the alpha-alumina used in this study. The powders were characterized by: X-ray diffraction (XRD), nitrogen adsorption isotherm, with specific surface area measured by BET method, thermogravimetric analysis (TG) and differential thermal analysis (DTA). The data show that the alpha-alumina obtained by burning the pseudoboehmite was highly pure.