Capsule free Hot isostatic pressing is a two-step pressure-assisted sintering method comprising a pressure-less sintering to the stage of reaching closed porosity and Hot isostatic pressing (HIP) on the final stage. The present work comprehends a systematic study both stages individually with the aim to produce highly transparent oxide ceramics with high-end properties. It was shown that very important parameter of capsule free HIP is so-called critical density where the pressure-less pre-sintering (stage 1) has to be terminated. After optimization of the whole sintering process, the real in-line transparency for Al₂O₃, MgAl₂O₄, and c-ZrO₂ ceramics was acquired as 70.4, 65.8 and 68.8 %, respectively, at a wavelength of 632.8 nm. Special attention was put through to preparation of transparent luminescent alumina ceramics doped by various rare earth elements (Eu, Er, Nd, Tb, Dy) as well as transition metals (Cr, Mn). The combination of superior optical (RIT exceeded 55%), luminescent and mechanical (Vickers hardness exceeded 25 GPa) properties allow these materials to become a promising candidate for number of hi-tech applications.
On the other hand, nearly fully dense BCZT-CeO₂ electroceramic was fabricated by spark plasma sintering (SPS) showing high dielectric permittivity of 5875 and low dielectric loss of 2.1%. An extraordinary optical transmittance of approx. 40% at a wavelength of 750 nm and approx. 46% in the infrared region was achieved.