Attaining near-theoretical densification in nanograined pyrochlore La2Zr2O7 (LZ) ceramic at 1150 degrees C by spark plasma sintering

摘要

Phase-pure Lanthanum zirconate nanopowders (La2Zr2O7, LZ) were synthesized by co-precipitation method and subjected to densification studies. No additive/sintering aid was used, neither was any slurry processing performed to improve the quality of the powders. LZ ceramic with near-theoretical density (>98%) was obtained at 1150 degrees C by spark plasma sintering; the lowest sintering temperature reported till date. The LZ ceramic comprised of small equiaxed grains (similar to 300 nm) and recorded a significant improvement in hardness (similar to 14 GPa) and scratch resistance measured by nanoindentation. The study clarifies that all previous reports involving poor sinterability of LZ system was related to inferior quality precursors. (C) 2016 Elsevier Ltd. All rights reserved.