Continuous BaTi_(1-y)Zr_yO_3 (0 ≤ y ≤ 1) nanocrystals synthesis in supercritical fluids for nanostructured lead-free ferroelectric ceramics

摘要

This paper addresses for the first time two of the main challenges in the field of electroceramics. The first one is the development of a continuous, fast and reliable synthesis method for producing sub-20 nm barium titanate zirconate (BaTi_(1-y)Zr_yO_3 with 0 ≤ y ≤ 1-BTZ) nanocrystals over the whole solid solution, while keeping a narrow size distribution. The second one concerns the processing of dense and nanostructured lead free electroceramics highlighting the size effect on the crossover from ferroelectric to relaxor, in the case of grains smaller than 100 nm. This was achieved combining the supercritical fluid technology to produce in continuous and at moderate temperature (400 ℃) BTZ nanocrystals, with Spark Plasma Sintering (SPS) to prevent grain growth during the sintering.