Preparation of non-stoichiometric Gd2+xZr2O7+3x/2 transparent ceramics by vacuum sintering

In this work, Gd2+xZr2O7+3x/2 (x = 0.1-0.6) transparent ceramics with high transmittance were prepared via vacuum sintering of nano powders (about 40 nm) synthesized by combustion method. The characterization results show that all powders are in defective fluorite structure, while the phase of ceramics change from ordered pyrochlore to disordered defective fluorite with the increase of Gd content. Excess Gd leads to lattice expansion, which makes the X-ray diffraction peaks of powders and ceramics shift to lower angle. Besides, there are pores in grain boundary and grain interior, and the main fracture mode exhibits typical transgranular fracture. The transmittance firstly increases and then decreases with the promotion of Gd content, and the Gd2.4Zr2O7.6 ceramic reach a highest in-line transmittance of 80% in the near-infrared range.