A new method, called the microwave-induced solution-polymerization synthesis (denoted as MW), and the conventional Pechini (denoted as PH) method have been used to prepare powders of La0.8Sr0.2Ga0.83Mg0.17O2.815 (denoted as LS(0.2)GM(0.17)) and La0.8Sr0.2(Ga0.9Co0.1)(0.83)Mg0.17O2.815 (denoted as LS(0.2)GCM(0.17)). A higher heating rate and a more homogenous heating manner without thermal gradients in the microwave oven resulted in a pure LSGCM powder after calcination at 1400 degrees C for 9 hours (h) and purer LSGM (6.2% secondary phases). The grain size of the pellets of the above two powders was 2-3 mu m without segregation. The densities of LS(0.2)GM(0.17)/MW and LS(0.2)GCM(0.17)/MW pellets, sintered at 1400 degrees C for 9 h, were 6.45 and 6.30 g cm(-3), respectively. (c) 2006 Elsevier B.V. All rights reserved.