CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Xin Wang,Yunfei Gao,Zhiyang Cai,Shan Hu,Junxian Zhang,Fuchen Wang,Yifei Wang
Chemical looping air separation (CLAS) represents a promising approach to use thermal energy for high-purity oxygen production. CeO 2 represents a class of material that uncouples oxygen using thermal energy, but the required temperature is usually very high (>1400 °C). This limits the potential use for CeO 2 -based materials in CLAS. This study reports a Pr doped CeO 2 oxygen sorbents for chemical looping air separation at ultra-low temperatures. The as-formed Ce 1-x Pr x O 2 solid solution can uncouple oxygen effectively, achieving a redox oxygen capacity of 0.88 wt% at isothermal condition as low as 500 °C. The redox oxygen capacity can be further enhanced to 1.63 wt% in temperature-swing cycles between 400 °C and 900 °C. Moreover, oxygen partial pressure-swing cycles show that the Ce 1-x Pr x O 2 solid solution maintains 95% of its redox oxygen capacity at oxygen partial pressure as low as 0.02 atm, indicating its potential applications in oxygen separation from diluted air. DFT calculations and other physio-chemical characterizations indicate that Pr doping can effectively reduce the oxygen vacancy formation energy, and gaseous oxygen is uncoupled when Pr 4+ and Ce 4+ are reduced in the Ce 1-x Pr x O 2 solid solution. Overall, this study highlights the novel performance of CeO 2 with Pr doping and could offer insights into CeO 2 modification strategies for thermal chemical applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Nanoscale
·
2022
·Vol. 14
·期 13
·5002-5009
·
IF 8.307
Tiantian Dai,Zanhong Deng,Shimao Wang,Xiaodong Fang,Gang Meng
With features of innate tunnels and oxygen vacancies derived from a unique geometrical structure and sub-stoichiometric compositions, W18O49 nanowires have been explored as multifunctional materials with diverse applications. Though thermal oxidation offers a facile method to synthesize patterned W18O49 nanowires, the relatively high growth temperature (≳500 °C) hinders their emerging applications in flexible or wearable electronics. In this work, aiming to lower the growth temperature of W18O49 nanowires by thermal oxidation, the temperature and oxygen partial pressure dependent growth has been systematically investigated for both W films and powders. W18O49 nanowires could be steadily obtained with appropriate temperature and oxygen pressure ranges for both cases, while the growth temperature of a W film (metastable β phase dominant) could be much lower than that of W powder (α phase). The structural analysis indicates that metastable β-W is susceptible to oxidation in comparison with α-W and thus generates oxidation-induced chemical compression for nanowire growth. The growth temperature of W18O49 nanowires could be reduced to ca. 400 °C, which paves the way for the in situ patterning of W18O49 nanowires on indium-tin-oxide (ITO) glass substrates and flexible substrates.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2022
·Vol. 29
·期 2
·248-255
·
IF 3.85
Ren Guoxing,Xiao Songwen,Liao Caibin,Liu Zhihong
As a part of the fundamental study related to the reduction smelting of spent lithium-ion batteries and ocean polymetallic nodules based on MnO-SiO 2 slags, this work investigated the activity coefficient of NiO in SiO 2 -saturated MnO-SiO 2 slag and Al 2 O 3 -saturated MnO-SiO 2 -Al 2 O 3 slag at 1623 K with controlled oxygen partial pressure levels of 10 −7 , 10 −6 , and 10 −5 Pa. Results showed that the solubility of nickel oxide in the slags increased with increasing oxygen partial pressure. The nickel in the MnO-SiO 2 slag and MnO-SiO 2 -Al 2 O 3 slag existed as NiO under experimental conditions. The addition of Al 2 O 3 in the MnO-SiO 2 slag decreased the dissolution of nickel in the slag and increased the activity coefficient of NiO. Furthermore, the activity coefficient of NiO ( γ NiO ), which is solid NiO, in the SiO 2 saturated MnO-SiO 2 slag and Al 2 O 3 saturated MnO-SiO 2 -Al 2 O 3 slag at 1623 K can be respectively calculated as γ NiO = 8.58 w (NiO) + 3.18 and γ NiO = 11.06 w (NiO) + 4.07, respectively, where w (NiO) is the NiO mass fraction in the slag.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 44
·16847-16856
·
IF 8.067
Wei Liang,Xiang Niu,Xiaodong Jian,Zhan Zeng,Junying Lai,Ting Wang,Weiping Gong,WenHan Zeng,Yingbang Yao,Tao Tao,Bo Liang,Sheng-Guo Lu
Barium strontium titanate (Ba0.7Sr0.3TiO3-BST) bulk ceramics were prepared using a conventional solid-state approach with different oxygen partial pressures in this work. The microstructures, oxygen vacancies, morphologies, permittivity and polarization were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, impedance analysis methods and polarization-electric field hysteresis measurements, respectively. The results indicated that the oxygen vacancies were introduced during the sintering in a reduced atmosphere, which leads to a significant impact on the electrocaloric effect (ECE) properties of BST ceramics. The ECE was measured directly using a thermocouple and modified differential scanning calorimetry. The optimal ECE temperature change of 2.18 K was obtained at 4 MV m−1 and 40 °C and a partial pressure of oxygen (PO2) of 6.14 × 10−7 atm, corresponding to an electrocaloric strength of 0.55 K MV−1 m−1.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 12
·15633-15642
·
IF 2.478
Luo Fan,Duan Zhongxia,Zhang Yuyang,Shang Yajing
For the industrial preparation of MnZn ferrite with high magnetic permeability and low magnetic loss, three-phase asynchronous machine was used to extrude MnZn ferrite magnet with large aspect ratio, and the final high-performance MnZn ferrite was obtained via subsequent tube furnace high-temperature sintering method. The effects of sintering temperature and oxygen partial pressure on the evolution of microstructure, and the electromagnetic and thermal properties for the MnZn ferrites were discussed systematically. The results showed that with the increase of the sintering temperature and oxygen partial pressure, both the effective permeability and quality factor show a trend of first increasing and then decreasing, and the highest values of them were obtained when the sintering temperature and oxygen partial pressure were 1260 °C and 3% oxygen partial pressure, respectively. The thermal conductivity exhibited a parabolic shaped trend with the increase of the oxygen partial pressure, and achieved maximum value at 3% oxygen partial pressure, while it decreased as the temperature increases further. The total magnetic loss of MnZn ferrite had a valley bottom temperature. As the oxygen partial pressure increased, the valley bottom temperature shifted to a higher temperature. The MnZn ferrite prepared with 3% oxygen partial pressure had the lowest total loss at 90 °C.
研究领域:
材料科学
·
电磁学
·
热物理学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 32
·15405-15414
·
IF 3.553
Wang Yige,Gao Bo,Wang Qian,Li Xiaohui,Su Zhi,Chang Aimin
The aim of this paper is to present a novel negative temperature coefficient (NTC) thermistor based on A 2 Zr 2 O 7 (A = Nd, Sm, Gd, Yb) zirconate ceramics with pyrochlore-type structure for high-temperature application. The zirconate ceramics were synthesized via a solid-state reaction method where rare-earth oxides and ZrO 2 were used as starting materials. The physical structures were characterized by X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. It was confirmed that Nd 2 Zr 2 O 7 and Sm 2 Zr 2 O 7 are pyrochlore phases, while Yb 2 Zr 2 O 7 and Gd 2 Zr 2 O 7 are defect fluorite phases. The electrical property investigated by using resistance–temperature measurements demonstrated that the prepared A 2 Zr 2 O 7 zirconate ceramics exhibit a typical characteristic of NTC over a wide temperature range between 673 and 1273 K. Particularly, A 2 Zr 2 O 7 , in addition to having high activation energy to ensure better sensitivity, can still maintain higher resistivity under high-temperature environments. Furthermore, the resistivity of A 2 Zr 2 O 7 is almost independent of the change in oxygen partial pressure. These properties are superior to the classical spinel-type or perovskite-type NTC thermistor, providing valuable information to explore new NTC thermistor for high-temperature applications.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·Vol. 50
·期 9
·15202-15208
·
IF 5.1
Xiong Huang,Pengfei Wang,Jianwei Zhao,Jun Yang,Zhenxiao Fu,Xiuhua Cao,Lei Zhang,Shuhui Yu,Rong Sun
As a dielectric material , BaTiO 3 -based ceramics are desirable for high performance ultra-thin multilayer ceramic capacitors (MLCCs) application. In this work, BaTiO 3 -based dielectric ceramics with superior dielectric properties were synthesized using a reducing atmosphere sintering process . It is found that the contribution of “wet" grain-boundary diffusion become significant as the oxygen partial pressure increases, resulting to a larger grain size and higher permittivity. Especially, for the specimen sintered in higher oxygen partial pressure , the stable temperature coefficient of capacitance (TCC) is dominated by irreversal domain due to the increase of super-lattice phase. Samples with higher oxygen partial pressure exhibit a higher permittivity of 2700 and better permittivity-temperature stability. Furthermore, ultra-thin MLCCs with thickness of 1 μm and capacitance of 10 μF and the TCC of X7R were successfully fabricated. This work provides a comprehensive explanation demonstrating upon the significant roles of grain size and defect engineering in the dielectric performance in BaTiO 3 -based ceramics, and points out an avenue to obtain excellent permittivity-temperature stability in ultra-thin MLCCs.
研究领域:
材料科学
·
电子陶瓷
·
介电材料
·
固态物理
·
功能陶瓷
·
电容器技术
✓ 已验证
DOI
高影响因子
CORROSION SCIENCE
·
2020
·
IF 6.479
Lian-Kui Wu,Jing-Jia Wu,Wei-Yao Wu,Hao-Jie Yan,Mei-Yan Jiang,Fa-He Cao
To improve the hot corrosion resistance, thickness controllable SiO 2 coating was electrodeposited on TiAl alloy. The hot corrosion behavior of the specimens contaminated with 75 wt.% Na 2 SO 4 + 25 wt.% NaCl salt mixture was investigated at 700 °C. Results showed that the generation of compact amorphous SiO 2 embedded with Na 2 Si 4 O 9 and cristobalite was responsible for the enhanced hot corrosion resistance. Moreover, the SiO 2 coating does not only act as a diffusion barrier to sulfur and chlorine but also decreases the oxygen partial pressure at the coating/alloy interface, therefore promoting the selective oxidation of Al to form protective Al 2 O 3 layer.
研究领域:
材料科学
·
腐蚀工程
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）