Large-scale preparation of powder composites xNiO/(1-x)Al2O3 in reactions of solution combustion synthesis

The conditions for the production of composites by Solution Combustion Synthesis (SCS) from reaction solutions of aluminum and nickel nitrates of various concentrations with glycine have been studied. The concentration of reaction solutions increases the product yield and the productivity of SCS process. The effect of the presence of Al3+ cations in reaction solutions on the combustion reaction intensity reduction has been established. The SCS precursors contained metallic nickel, nickel oxide and amorphous alumina. The phase composition of the samples changed in the process of annealing: nickel oxidation, crystallization of gamma-Al2O3 (600 degrees C) and formation of NiAl2O4 spinel (600-800 degrees C) were observed. The maximal specific surface area value recorded after annealing at 800 degrees C was 59-63 m(2)/g. In samples obtained with a lower fuel content, gamma-Al2O3 or a mixture of gamma-Al2O3 and NiAl2O4 crystallize on the surface of composite particles. The concentration of NiO on the surface of composites obtained from precursors synthesized from concentrated solutions at phi = 1.4 is close to the nominal composition. (C) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Automated summary

The study examined the conditions for producing composites using Solution Combustion Synthesis (SCS) from reaction solutions of aluminum and nickel nitrates with glycine. The concentration of reaction solutions was found to increase product yield and process productivity, while the presence of Al3+ cations in the reaction solutions was observed to reduce combustion reaction intensity. The phase composition of the materials changed during annealing, with the formation of gamma-Al2O3 and NiAl2O4 spinel at different temperatures.