Room-temperature synthesis of apatite-type lanthanum silicates by mechanically milling constituent oxides

Enhanced sinterability of mechanical alloyed La9.33Si2Ge4O26 oxyapatite powders for IT-SOFC electrolytes

“…Poor control of grain morphology, grain growth and GeO 2 volatilization above $1300 8C [14][15][16] require careful consideration, as well as other key properties rather than just the high ionic conductivity need to be optimized such as thermo-mechanical properties. In this context, mechanical alloying (MA) is regarded as a potential alternative processing method to obtain apatite-like lanthanum oxide conductors at reduced costs [7,17,18]. During the MA process, heavy deformation is introduced into the particles, increasing the defect density, which accelerates the diffusion process by decreasing the diffusion distances.…”

Synthesis of lanthanum silicate oxyapatite materials as a solid oxide fuel cell electrolyte

“…To overcome these problems, other methods have been developed such as mechanochemical synthesis and sol-gel route. 2,[10][11][12] However, the sol-gel route implies several heating steps to promote the formation of a gel and ensure the removal of all the organic components. Mechanochemical synthesis needs a long milling time (higher than 9 h) of the starting mixture.…”

Rare-earth Element-bearing Apatites and Oxyapatites

“…During recent decades, oxyapatite 2 -type structure with the general formula: REE 9.33+x Si 6 O 26+3x/2 (where REE is rare-earth element) [3], [4], REE 9.33 □ 0.67 (SiO 4 ) 6 O 2 [5] or REE 10−x (SiO 4 ) 6 O 2+y [6] has attracted considerable attention as oxide ion conductors. Apatite-type oxides have attracted much attention as the material for electrolytes in solid oxide fuel cell and sensors (Chapter 10).…”

“…The ionic conductivity increases with the increasing size of REE cations. 3 The mechano-chemical synthesis of apatite-type lanthanum silicates from the mixture of La 2 O 3 and amorphous silica without post-milling thermal treatment was described by FUENTES et al [4].…”