Design and characterization of spinnable carboxylate-based La-Zr oxide precursor towards scalable preparation of micro/nano lanthanum zirconate fibers for thermal management

Rare earth zirconates have incomparable chemical thermophysical properties, yet the difficulty of preparation methods limit their application as fibrous material. In present work, a spinnable La2Zr2O7 precursor, named as carboxylate lanthanum-zirconium (COLZ), was developed using carboxylic acids as structural and functional ligands. When COLZ is in its liquid state, it can be readily processed into desired shapes, allowing preparation of high aspect ratio precursor fibers with dense and bonding-strong internal structures. The spinnability was explained by the transformation from solid to liquid state under external forces, in which dynamic bridging of carboxylate and hydroxyl between nano-sized colloidal particles play a key role. Due to weakly acidic ligands, organics in COLZ can be easily removed, making direct heat treatment at the target temperature possible, which is beneficial for massive production. The strategy of developing spinnable precursor could also be applied to prepare other rare earth zirconate fibers or new multi-oxide fibers.