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Bi2O3 ceramics with high density were prepared by low temperature sintering using acetic acid as the co-solvent. The effect of acetic acid concentration, pressure, temperature and holding time during sintering on the densification of Bi2O3 ceramics was investigated. The Bi2O3 ceramic with a relative density of 98.31% was obtained by low temperature sintering at 270 ℃/330 MPa for 140 min using 3 mol/L acetic acid solution. The densification mechanism for low temperature sintering Bi2O3 ceramic followed "dissolution–precipitation–growth", which is different from the densification mechanism of the traditional high-temperature sintered ceramics. The Bi2O3 ceramic with a permittivity (εr) ~ 32.2, a quality factor (Qf) ~ 16,425 GHz and a grain size ~ 4.2 μm was obtained. The study provides a new method of ceramic development by low temperature sintering. [ABSTRACT FROM AUTHOR]

High-density ZnO ceramics were prepared by a Two-Step Cold Sintering Process (TS-CSP) at an ultralow-temperature. The densification process of ZnO ceramics was demonstrated by TS-CSP. And the density, microstructure and electrical properties of the ZnO ceramics were investigated. The results indicate that most of the crystallization of ZnO ceramic can be completed in the first step of sintered at 150 °C/200 MPa for 30 min, with a relative density approaching 97.36%. This relative density was further improved to 99.43% after the second sintering step was deployed at 200 °C/200 MPa for 30 min, which displayed an average grains size of 1.5 μm and resistivity of 0.125 Ω cm. This work demonstrated an effective method to reduce CSP temperature and pressure in the production of high-performance ZnO ceramics. [ABSTRACT FROM AUTHOR]

Highly efficient solar cells demand transparent and conductive oxide films with high electronic mobility. Decreasing SnO 2 content in In 2 O 3 targets (ITO) is one of important ways, but resulting in difficulty of sintering densification. ITO targets with SnO 2 contents of 1 wt%, 2 wt.% and 3 wt% were prepared by microwave sintering. Harmless sintering additives of TiO 2 and trances of SiO 2 promotes sintering densification. All the targets show the cubic bixbyite phase and dense microstructure. The fine grains with the average size of several microns were obtained. Higher sintering temperature contributes to eliminating the pores in targets, enhancing density and decreasing resistivity. The optimal sintering temperature of 1550 °C obtains the highest relative density (>99 %) and low resistivity (<3.4 × 10−4 Ω cm). The enhanced density of these ITO targets with low SnO 2 content can effectively inhibit the formation of nodules on the surface of target during magnetron sputtering. [ABSTRACT FROM AUTHOR]

When the traditional method is used to prepare IGZO ceramic, it needs to be sintered under ultra-high temperatures and for a long time, and the preparation cost is high. To reduce the sintering temperature and energy consumption, a mixed-phase IGZO green compact with ultra-high density was first prepared using cold sintering process. Then, the IGZO ceramic with excellent properties was successfully prepared by the conventional sintering method at low sintering temperature. The effects of sintering temperature on the microstructure, density, and electrical properties of IGZO green compact and ceramic were studied. The densification process of ultrahigh density IGZO green compact was also discussed. The results show that the IGZO green compact with a relative density of over 96% can be obtained under cold sintering at 400 °C/475 MPa and assisted by the acetic acid solution. An IGZO ceramic with a relative density of 98.12% and resistivity of 4.87 × 10−3 Ω cm was obtained by sintering at 1100 °C for 5 h. This paper provides a reference for improving green compact density and preparing high-performance transparent oxide ceramics at low temperature. [ABSTRACT FROM AUTHOR]

The development of optoelectronic devices depends on the development of optoelectronic materials such as transparent ceramics. LiF transparent ceramics are photoelectronic ceramics with excellent photoelectric properties. Still, the traditional preparation of LiF transparent ceramics generally needs a high temperature or high-pressure environment, and the cost is high. This paper adopts a cold sintering process to prepare high-density LiF transparent ceramics at low temperatures to reduce the preparation conditions. The effects of different cold sintering temperatures on microstructure, density, hardness, visible and near-infrared transmittance, and electrical properties of transparent ceramics were studied. The results show that using LiOH solution as the solvent, the relative density of LiF ceramics can reach up to 99.64% under the sintering condition of 375 °C/470 MPa, and the Vickers hardness is 1.34 GPa. Vickers hardness is 1.34 GPa. The transmittance in the visible and near-infrared regions is 60.45% and 85.31%, respectively. The dielectric constant and dielectric loss of 13 GHz are 4.36 and 1.11 × 10−3, respectively. [ABSTRACT FROM AUTHOR]

It is important to prepare high-performance sputtering ceramic targets to meet the coating-film requirements of industrialized transparent conductive films. The sintering temperature and time required to prepare ITO ceramic targets following traditional methods are generally 1600 °C and 168 h, respectively. The process involves consuming much energy, and a high amount of precious metal (indium) is present in the target. High-density In–Zn–Sn–O (IZTO) ceramic targets were prepared following the cold sintering process using IZTO powders with different ITO contents to reduce the sintering temperature and the content of precious metal indium and shorten the preparation time. The electrical properties of the targets could be improved by two orders of magnitude when annealed at a reducing atmosphere. The experimental results revealed that an IZTO target with a relative density of 93.65% and a resistivity of 6.7 × 10−2 Ω cm was prepared in the presence of 40 wt% ITO under the condition of cold sintering at 300 °C/1.0 h. The resistivity was as low as 6.0 × 10−4 Ω cm when annealed at 500 °C/1.0 h in a reducing atmosphere. In this study, a high-performance IZTO ceramic target with low indium content was prepared at a low temperature and within a short time. [ABSTRACT FROM AUTHOR]