Plasma spray synthesis of La10(SiO4)6O3 as a new electrolyte for intermediate temperature solid oxide fuel cells

The apatite-type lanthanum silicate films were successfully synthesized by modified atmosphere plasma spraying using lanthanum oxide and silicon oxide mixed powders and precalcined hypereutectic powders in the size range 1–3 μm and 5–8 μm, respectively, as starting feedstock materials. The films differed not only in microstructural scale, but also in the characteristic of the degree of film densification. A detail describing the evolution of microstructure has been discussed. A considerable improvement in densification of the La₁₀(SiO₄)₆O₃ electrolyte films has been observed.