RESEARCH ON FABRICATION OF AMMONIUM ALUM PRECURSORS FROM ALUMINUM HYDROXIDE, APPLY IN PRODUCTION OF PURE Al2O3

Abstract

The demand for high-purity (over 99%) and fine (particle size less than 1 µm) aluminum oxide powder is
increasing because this type of powder is essential in various industries such as semiconductor
manufacturing, optical devices (LEDs, lasers, etc.), microelectronic components, and medical ceramics
(artificial bones and joints). The properties of Al2O3 materials, which are highly resistant to corrosion
and wear and have good thermal conductivity, make them valuable. In this study, pure and fine α-Al2O3
aluminum oxide powder were prepared using the sol-gel method. The result is a sol system, including
nano-sized Al(OH)3, which bonds and forms a transparent gel permeated by urea solution and
[Al13O4(OH)24(H2O)12]
7+ complex ions. The formed gel is calcined at 300°C to produce γ-alumina, which
then transitions to α-Al2O3 at temperatures above 1000°C.