Optimization of the hydrothermal synthesis of La0.7Sr0.3MnO3 + δ using an original optimal experimental design

This paper shows one example of synthesis using optimal design methodology in material science. The aim is to determine the initial concentrations in lanthanum, strontium and manganese which have to be introduced in the reaction medium to obtain by hydrothermal synthesis the manganite powder of composition La0.7Sr0.3MnO3 + δ. Two original designs, in which two of the precursors concentrations vary, are built to estimate the parameters (or effects) of two predictive quadratic models giving the strontium and lanthanum proportions vs. strontium and manganese concentrations (design 1) and vs. strontium and lanthanum concentrations (design 2), the third precursor concentration being fixed. The sole triplet of concentrations leading to the hoped oxide is obtained at the issue of 18 runs. The repeatability of the procedure is checked by synthesizing three times the manganite of composition La0.7Sr0.3MnO3 + δ.