Single-step combustion synthesis of LaAlO3 powders and their sintering behavior

Single-phase LaAlO3 was prepared by a simple combustion synthesis procedure, which relies on using urea and β-alanine fuel mixture, instead of a single fuel. The aqueous solution of La(NO3)3, Al(NO3)3, urea and β-alanine underwent a strong exothermic reaction at 281 °C, thus enabling the formation of single-phase LaAlO3 directly from the combustion reaction—without the need of supplementary annealing. The combustion synthesized LaAlO3 had an average crystallite size of 46 nm and a BET surface area of 3.0 m2/g. The addition of NaCl to the reaction mixture decreased the combustion temperature, promoting an increase of the BET surface area (8.5 m2/g). At the same time the LaAlO3 crystallite size decreased to 36 nm. After sintering at 1500 °C for 5 h, LaAlO3 pellets developed a fine microstructure, reaching 94% of the theoretical density.