Nano-alumina powders/ceramics derived from aluminum foil waste at low temperature for various industrial applications

In this work, nanoscale single crystalline gamma- and alpha-alumina powders have been successfully prepared from aluminum foil waste precursor via co-precipitation method using NH4OH as a precipitant. The obtained gel after co-precipitation treatment, was calcined at different temperatures (500,700, 900,1050, 1100, 1300 and 1500 degrees C) and the products were characterized by XRD, FTIR and HRTEM. The results revealed that nano-gamma-Al2O3 was fully transformed to nanometer-sized alpha-Al2O3 (36-200 nm) after annealing at temperatures as low as 1100 degrees C. The thermally preheated powder at 500 degrees C was further pressed under 95 MPa by the uniaxial press and the obtained bodies were found to have98.82% of the theoretical density, 1.18% porosity and 708 MPa compressive strength, when sintered at temperatures as low as 1600 degrees C without using any sintering aid. These excellent results proved that this work will contribute to finding a commercial source for preparing sub 100 nm alpha-alumina through the secondary resources management and even more so to synthesizing strong alpha-Al2O3 bodies which are promising in terms of their structure and compression. The alpha-Al2O3 bodies synthesized by the present work could be used as a feedstock for fabrication of various kinds of functional and structural materials that are extensively used in high tech. (C) 2016 Elsevier Ltd. All rights reserved.