Synthesis and characterization of lanthanum aluminate powders via a polymer complexing plus combustion route

Highlights: ► Polymer complexing plus combustion route is a widely used method to produce complex oxide powders. ► In this paper, we investigated the influence of different complexing polymers, PVA and PEG, to the phase evolution and sintering properties of lanthanum aluminate. ► To obtain better quality LaAlO3 powders, PEG is preferred over PVA. ► We thus concluded that it is more important to get powders with desirable morphology and less agglomeration when different polymers can be selected for the synthesis of complex oxides. - Abstract: Lanthanum aluminate powders were prepared by a simple polymer complexing plus combustion method using PVA or PEG as complexing agent and fuel. The influence of different polymers on phase purity, powder morphology and sintering performance were investigated. Trace amount impurity La2O3 exists in the PEG powder, but it could be eliminated after high temperature sintering. The pure phase LaAlO3 can be easily obtained in PVA powders calcined at 950 °C even severe aggregation always exists. PEG shows advantages over PVA in terms of the densification and microstructure control during sintering process. The high relative density of 97.0% and homogeneous fine microstructure with grain size < 3 μm can be obtained in the PEG-derived sample sintered at 1600 °C for 5 h. To obtain better quality LaAlO3 powders through combustion route, PEG is preferred over PVA.