Lanthanum zirconate nanoparticles and ceramics produced using a nitrate-modified alkoxide synthesis route

A Novel Chemical Route to Prepare La2Zr2O7 Pyrochlore

“…Lanthanum zirconate ceramics with near theoretical density can be obtained using hot isostatic pressing at 1500°C for 2 h using 196 MPa (99.5% relative density) . Furthermore, Ion et al . has reported a nitrate‐modified alkoxide‐based sol–gel process combined with additional milling steps in acetone and cold isostatic pressing at 500 MPa before sintering at 1400°C which yields a ceramic with 97.9% theoretical density.…”

“…All wet‐chemistry methods involve mixing precursors at the molecular level, thus producing materials with high compositional homogeneity and stoichiometry control. Common methods reported for preparation of lanthanum zirconate include sol–gel processing, coprecipitation, hydrothermal or solvothermal synthesis, complex combustion, and the Pechini method …”

“…In this method, metal alkoxides form gels through hydrolysis and poly‐condensation reactions, with subsequent gel converted to oxide powders by heat treatment at relatively low temperature and milling processing. However, the most commonly used metal alkoxides are extremely sensitive to moisture, necessitating the use of a stabilizer (e.g., citric acid in the Pechini method) or nonaqueous solvents . Contrary to the mixed‐oxide method, in which the reaction takes place between micrometer and submicrometer sized particles, the sol–gel route ensures very good mixing of the species at the nanoscale level, although the reaction between the metallic species still proceeds as a solid‐state reaction upon heating .…”

Characterization of lanthanum zirconate prepared by a nitrate-modified alkoxide synthesis route: From sol to crystalline powder

“…Details of the synthesis are presented elsewhere. 13 The dehydrated La(NO 3 ) 3 solution (LNsol) was used in the synthesis of lanthanum zirconate sol (LZ-sol). The LZ-sol was then dried by heating at 150 • C for 12 h (LZ-dried), where a strong exothermic reaction was noticed.…”

“…We have shown that the nitratemodified alkoxide-based route is an attractive option. 13 To the authors' knowledge there are no studies of the nitrate-alkoxide synthesis pathway, especially of its early stages. Moreover, the role of nitrates in the alkoxide-based sol-gel synthesis has not been studied.…”