Novel cubic Y4Zr3O12 transparent ceramics with high refractive index fabricated by pressureless sintering

In this work, a novel Y 4 Zr 3 O 12 transparent ceramic was first and simply fabricated via pressureless sintering in air without additives. The as-prepared Y 4 Zr 3 O 12 ceramics exhibited a single-phase cubic fluorite structure. And all open pores got closed at a critical density of ∼93.5 %. Moreover, Y 4 Zr 3 O 12 ceramic showed significant transparency in the visible wavelength when sintered between 1525 and 1625 °C. Peak performance was observed in the 1600 °C-sintered ceramic with an average grain size of ∼1.53 μm, achieving the highest in-line transmittance of 63.1 % at 600 nm (1 mm thickness), which approached 80 % of the theoretical limit. The optimal Y 4 Zr 3 O 12 sample had a high refractive index of ∼2.04 at 600 nm, a large Abbe’s number of ∼53.4, an oxygen ion polarizability of 2.28 ± 0.06 Å 3 , and an optical basicity of 0.94 ± 0.03. These results position transparent Y 4 Zr 3 O 12 ceramic as a promising candidate for diverse applications, spanning optical/photonic devices and high-performance transparent windows for consumer electronics.