Structural evolution of Al2O3-ZrO2-La2O3 fibrous membrane and the effects on high-temperature stability

Structural evolution is essential for the fundamental understanding of high-temperature behavior and optimizing of ceramic micro/nanofibers. In the present work, the effects of structural evolution on the high temperature stability and flexibility of Al 2 O 3 -ZrO 2 -La 2 O 3 (AZLO) fibrous membranes were fully investigated. The evolution of precursor fiber pyrolysis, phase transformation and microstructure were characterized by TG/DSC, IR, XRD, SEM, ESB and HRTEM. From 800 to 1200°C, the dual-phasic structure of amorphous Al 2 O 3 and fine ZrO 2 and La 2 Zr 2 O 7 grain contributed to the thermal stability and flexibility of AZLO fibrous membranes. At 1300°C, solid-state metathesis reaction between amorphous Al 2 O 3 and intermediate phase La 2 Zr 2 O 7 led to the formation of fine LaAl 11 O 18 and ZrO 2 grain. The interlaced distribution of fine ZrO 2 particles and platelet-like LaAl 11 O 18 became the new fundament of thermal stability and flexibility of AZLO fibrous membranes. AZLO fibrous membranes could maintain its excellent high temperature stability and flexibility up to 1300°C and possessed a low room temperature thermal conductivity of 35.7 mW m −1  K −1 . The present work provided a novel perspective for the rational design of Al 2 O 3 -ZrO 2 fibers from the view of structural evolution.