Transparent ceramics have various potential applications such as infrared (IR) windows/domes, lamp envelopes, opto-electric components/devices, composite armors, and screens for smartphones and they can be used as host materials for solid-state lasers. Transparent ceramics were initially developed to replace single crystals because of their simple processing route, variability in composition, high yield productivity, and shape control, among other factors. Optical transparency is one of the most important properties of transparent ceramics. In order to achieve transparency, ceramics must have highly symmetric crystal structures; therefore, the majority of the transparent ceramics have cubic structures, while tetragonal and hexagonal structures have also been reported in the open literature. Moreover, the optical transparency of ceramics is determined by their purity and density; the production of high-purity ceramics requires high-purity starting materials, and the production of high-density ceramics requires sophisticated sintering techniques and optimized sintering aids. Furthermore, specific mechanical properties are required for some applications, such as window materials and composite armor. This review aims to summarize recent progress in the fabrication and application of various transparent ceramics.

Materials development and potential applications of transparent ceramics: A review

An atomic-scale and high efficiency finishing method of zirconia ceramics by using magnetorheological finishing

Structure-transmittance relationship in transparent ceramics

In this study, ZrO2 and Zn-ZrO2 nanoparticles (NPs) with a series of Zn ion doping amounts were synthesized by the sol-gel process and utilized as substrates for surface-enhanced Raman scattering (SERS). After absorbing the probing molecule 4-mercaptobenzoic acid, the SERS signal intensities of Zn-ZrO2 NPs were all greater than that of the pure ZrO2. The 1% Zn doping concentration ZrO2 NPs exhibited the highest SERS enhancement, with an enhancement factor (EF) value of up to 104. X-ray diffraction, X-ray photoelectron spectroscopy, Ultraviolet (UV) photoelectron spectrometer, UV-vis spectroscopy, Transmission Electron Microscope (TEM), and Raman spectroscopy were used to characterize the properties of Zn-ZrO2 NPs and explore the mechanisms behind the SERS phenomenon. The charge transfer (CT) process is considered to be responsible for the SERS performance of 4-MBA adsorbed on Zn-ZrO2. The results of this study demonstrate that an appropriate doping ratio of Zn ions can promote the charge transfer process between ZrO2 NPs and probe molecules and significantly improve the SERS properties of ZrO2 substrates.

https://www.mdpi.com/2079-4991/9/7/983/pdf

Improved Surface-Enhanced Raman Scattering Properties of ZrO2 Nanoparticles by Zn Doping.

To obtain red-emitting luminescent material for high-power UV LED and UV LD applications, an additive-free Y2O3:Eu3+ phosphor ceramic was successfully prepared in this work. The nitrate pyrogenation method is applied to obtain raw nanopowders with high reactivity, and a hybrid sintering method combining low-temperature presintering and subsequent hot isostatic pressing (HIP) is then applied to realize full densification of the final ceramic products. The effects of the presintering temperature on the density, microstructural, and optical properties are investigated in detail. The HIP-treated Y2O3:Eu3+ ceramic presintered at 1450 °C exhibits a high transmittance near 80 % at 600 nm. Due to the nonuse of sintering additives, the thermal conductivity of Y2O3:Eu3+ ceramic product reaches 10.9 Wm−1 K−1 at room temperature. The achieved Y2O3:Eu3+ ceramic also exhibits good applicability under the excitation of a UV LED chip and UV laser light, showing promise as a color converter for high-power UV LED and UV LD applications.

Additive-free Y2O3:Eu3+ red-emitting transparent ceramic with superior thermal conductivity for high-power UV LEDs and UV LDs

Investigation of optical, mechanical, and thermal properties of ZrO2-doped Y2O3 transparent ceramics fabricated by HIP

Fabrication of transparent yttria ceramics by alcoholic slip-casting

In the present study, a tough tetragonal zirconia polycrystalline (Y-TZP) material was developed for use in high-speed infrared windows and domes. The influence of the preparation procedure and the microstructure on the material’s optical properties was evaluated by SEM and FT-IR spectroscopy. It was revealed that a high transmittance up to 77% in the three- to five-micrometer IR region could be obtained when the sample was pre-sintered at 1225 °C and subjected to hot isostatic pressing (HIP) at 1275 °C for two hours. The infrared transmittance and emittance at elevated temperature were also examined. The in-line transmittance remained stable as the temperature increased to 427 °C, with degradation being observed only near the infrared cutoff edge. Additionally, the emittance property of 3Y-TZP ceramic at high temperature was found to be superior to those of sapphire and spinel. Overall, the results indicate that Y-TZP ceramic is a potential candidate for high-speed infrared windows and domes.

https://www.mdpi.com/1996-1944/10/4/390/pdf

Preparation and Optical Properties of Infrared Transparent 3Y-TZP Ceramics

Optical and thermal properties of TiO2-doped Y2O3 transparent ceramics synthesized by hot isostatic pressing

A modified vibrating screen method was employed to prepare granulated Y2O3 powders, which were used to fabricate transparent ceramics The granulation process was carried out with yttrium-stabilized zirconia balls (5 mm in diameter) in a 200-mesh screen, which was vibrated by a Heidolph shaker After passage through the vibrating screen, the sub-micron Y2O3 particles were converted into large granules and collected in the bottom chamber of the sieve Compared with the original powders, the granulated powders had a smaller repose angle of 3409° and larger apparent and tap densities with sharp rises of 5054 and 3207%, respectively, indicating a good flowability and filling properties A high transmittance of 82% at 2500 nm was achieved for ceramics prepared using the granulated powders by vacuum sintering and hot isostatic pressing (HIP)

Yangyang Xu

Papers

Investigation of optical, mechanical, and thermal properties of ZrO2-doped Y2O3 transparent ceramics fabricated by HIP

Fabrication of transparent yttria ceramics by alcoholic slip-casting

Preparation and Optical Properties of Infrared Transparent 3Y-TZP Ceramics

Optical and thermal properties of TiO2-doped Y2O3 transparent ceramics synthesized by hot isostatic pressing

Granulation of Y2O3 powders by a vibration method for the preparation of transparent ceramics