Transmittance enhancement of La0.4Gd1.6Zr2O7 transparent ceramic by aqueous AM gel-casting with pretreated powder

Abstract

Via a powder pretreatment process, transparent La0.4Gd1.6Zr2O7 ceramics were successfully fabricated through the aqueous AM (acrylamide) gel-casting technique. Our research shows that the water absorption of La2O3 has significant influence on the viscosity of slurry, leading to low density of the green body and poor transparency of ceramic. By pretreating the mixed powder via a solid-state reaction, the viscosity and pH results have shown that the single-phase pretreated powder has a positive improvement on the gel-casting process. Compared with the mixed powder, the pretreating method has effectively improved the slurry with higher solid content and lower viscosity. Therefore, the pretreated powder combined with gel-casting method have a positive influence on the density of green body and the optical quality of obtained La0.4Gd1.6Zr2O7 ceramics. The polished ceramics with 40 mm in diameter (Ø = 40 mm) and 1.5 mm in thickness (δ = 1.5 mm) exhibited the in-line transmittance of 78% at 1100 nm and a maximum transmittance of about 80% in the infrared region, as well as a wide range of high stable transmittance among 0.6–6.0 µm wavelength. Our work opens a way for highly transparent ceramic preparation by aqueous AM gelling system with hygroscopic rare earth oxide as raw materials.