Effect of rate-controlled sintering on characteristics of hot isostatically pressed transparent Yb-doped Lu2O3 ceramics

Ytterbium-doped transparent lutetium oxide (Yb:Lu2O3) ceramics were fabricated from laser ablated nanoparticles via vacuum pre-sintering followed by hot isostatic pressing (HIPing). Nano-sized powder was uniaxially pressed and pre-sintered at 1550 °C using a conventional regime composed of a slow ramp (3 °C/min) with subsequent holding (CRH), and a rate-controlled sintering (RCS) regime consisting of a progressive reduction in densification rates. Although the pre-sintered samples approached identical relative density of ∼97%, the average grain size was decreased more than 30% by application of RCS regime. Pre-sintered Yb:Lu2O3 compacts were then HIPed to achieve full density and transparency. The optical attenuation coefficient of the ceramic pre-sintered by CRH regime was found to exceed that of the ceramic fabricated using RCS method by a factor of 2.1 at the wavelength of 1080 nm.