Influence of Co‐Doping on the Sintering Path and on the Optical Properties of a Submicronic Alumina Material

Sintering in air was performed on pure and CaO/TiO 2 co‐doped slip cast α‐alumina samples. The relative density/grain size relationship, referred to as sintering path, has been obtained for each composition. Fully dense samples were obtained after an additional hot isostatic pressing (HIP) step on the pure and doped materials. After grinding and polishing, the optical properties were measured on flat windows (thickness around 1 mm) in the ultraviolet, visible, close‐infrared, and mid‐infrared ranges. The influence of a tiny residual porosity on the optical properties, impossible to quantify using standard methods, has been investigated.