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

Via a powder pretreatment process, transparent La 0.4 Gd 1.6 Zr 2 O 7 ceramics were successfully fabricated through the aqueous AM (acrylamide) gel-casting technique. Our research shows that the water absorption of La 2 O 3 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 La 0.4 Gd 1.6 Zr 2 O 7 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.