Effects of Y Doping on Phase Structure, Microstructure and Electrical Conductivity of La10−xYxSi6O27 (x = 0, 0.1, 0.2, 0.3)

La_10−xY_xSi₆O₂₇ (x = 0, 0.1, 0.2, 0.3) ceramics were prepared by a two-step ball-milling method. This study aims to address the research gap in Y³⁺ doping of lanthanum silicate systems by systematically investigating the synergistic effects of Y³⁺ doping concentration on the phase structure stability, microstructural evolution, and total conduction behavior of apatite-type electrolyte materials. La_10-xY_xSi₆O₂₇ belongs to the hexagonal apatite structure, while the La₂SiO₅ secondary phase emerged when x ≥ 0.2. As the Y content continues to increase, a few pores appear in the sintered body, and Y ions are effectively integrated into the lattice of lanthanum silicate. The x = 0.1 sample demonstrates the maximum conductivity of 7.26 × 10^-3 S cm⁻¹ at 800°C, whereas the x = 0.2 composition shows an order-of-magnitude decrease in conductivity due to pore formation.