MATERIALS & DESIGN
·
2016
·
IF 3.997
Shugang Chen,Yanzi Gou,Hao Wang,Ke Jian,Jun Wang
In order to prepare ZrC-ZrB 2 nanocomposite ceramics with high temperature stability from single-source precursors, the reactions of ZrCl 4 , allyl amine, allyl-MgCl and borane were employed to synthesize suitable precursors. The meliorated ZrNCB precursor had favorable solubility and higher ceramic yield (68.8 wt%), which was then transformed to ZrC-ZrB 2 ceramics at different temperatures. The main phase of the ceramics was amorphous at 1000 °C. As the temperature increased, the amorphous phases started to crystallize, resulting in the appearance of ZrC and ZrB 2 peaks. The content of ZrC and ZrB 2 phases was relatively high in the nanocomposite ceramics at 1600 °C (over 80 wt%). The ZrC-ZrB 2 nanocomposite ceramics showed good high temperature stability up to 2000 °C. Oxidation test indicated that an oxide layer was formed on the ceramic surface at 1700 °C under air to prevent further oxidation of the ceramics. With excellent high temperature and oxidation resistances , the ZrC-ZrB 2 nanocomposite ceramics have potential application for advanced rocket engines and nuclear industry.
研究领域:
材料科学
·
陶瓷
·
高温材料
·
纳米复合材料
·
航空航天工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·Vol. 49
·期 4
·5770-5775
·
IF 5.532
Yan Hao,Yibo Zhang,Biao Liu,Kuibao Zhang
In this work, MgAl 2 O 4 : Cr 3+ transparent ceramics have been synthesized by the hot press sintering techniques, and the effect of the sintering aid Gd 2 O 3 and its content on the densification, microstructure, and optical, photoluminescence was studied and discussed. The relative density reached 99.29% with 0.8 wt% Gd 2 O 3 as a sintering aid, and the optical transmittance at 686 nm and 1446 nm were approximately 76%. As Gd 2 O 3 content continued to increase, the grain size of the ceramics became smaller and uniform, accompanied by some pores with the size of ～1 μm. The ceramics with 4.0 wt% Gd 2 O 3 showed a higher transmittance, of 82% at 1446 nm. Additionally, Gd 2 O 3 was helpful for Cr 3+ in the sites of octahedral symmetry, which increased the quantum yield. The quantum yield of MgAl 2 O 4 : Cr 3+ with 0.8 wt% Gd 2 O 3 was about 0.175, which was 36% higher than that of ceramic without Gd 2 O 3 . In short, the sintering aid Gd 2 O 3 not only contributed to improving the densification, homogenizing the grain size, and heightening the optical transmittance but also enhanced the quantum yield of Cr 3+ .
研究领域:
材料科学
·
陶瓷
·
光学材料
·
固体物理
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 7
·8450-8459
·
IF 2.478
Zhang Pengfei,Ma Weibing,Wang Shenghui,Guo Jingdong,Hong Jingnan,Ba Ruiqing,He Xinghui,Li Jing
Aurivillius-type piezoceramics, Na 0.15− x Li x Bi 2.85− x Ce x Ti 0.7 Nb 1.3 O 9 (NBTN-LC100 x ; x = 0, 0.02, 0.04, 0.06), were fabricated by the solid-state reaction method. The crystal structure, surface microstructure, and electrical properties of NBTN-LC100x ceramics were studied systematically. The XRD revealed that the (LiCe) co-doping induced lattice distortion and the orthogonality of ceramics were weakened. The grain size decreased obviously from 23.1 to 9.1 µm and the Curie temperature ( T C ) decreased from 877 to 853 °C as the increase of (LiCe) content. As x = 0.04, the NBTN-LC100 x (NBTN-LC4) ceramics had the best performance, its T C , tanδ at 500 °C, E C , and P r were 861 °C, 7.61%, 62 kV/cm, and 3.4 µC/cm 2 , respectively. The piezoelectric property was enhanced significantly and optimal d 33 value was about 20.7 pC/N at x = 0.04 for NBTN-LC100 x ceramics. In addition, the NBTN-LC4 ceramics possessed a good thermal stability after annealing at 850 °C for 2 h. The high d 33 , high T C , low tanδ, good thermal stability of NBTN-LC4 ceramics make it is potential candidate in high-temperature electronic devices.
研究领域:
材料科学
·
陶瓷
·
压电材料
·
固态化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Shengquan Yu,Wei Jing,Mingjing Tang,Tao Xu,Wenlong Yin,Bin Kang
The highly transparent Nd:YAG ceramics were prepared by using powders synthesized by citrate sol-gel method. The citrate sol-gel method could avoid defects of the solid-phase reaction method and the liquid phase co-precipitation method in preparing Nd:YAG ceramic powders with the ratio of (Nd 3+ , Y 3+ ):Al 3+ equal to 3:5. The dried gel was the three dimensional net-shaped porous structure. When the dried gel was calcined at 500 °C in oxygen, pure YAG phase formed directly with no intermediate phases. The Nd:YAG powders calcined at 800 °C had maximum particle size near 500 nm. These powders were not equiaxed and there were dumbbell-like and annular grains. The highly compact Nd:YAG ceramics could be well sintered at 1750 °C for 12 h in vacuum atmosphere, and these sample had the average grain size about 3.8 μm. The polished Nd:YAG ceramics was highly transparent, and the transmittances at 1064 nm and 400 nm were 83.4% and 74.2%, respectively. The fluorescence emission spectrum implied high possibility of realizing laser output at 1064 nm by pumping at 808 nm. Generally, the citrate sol-gel method was also a reliable choice for preparing high quality Nd:YAG transparent ceramics.
研究领域:
材料科学
·
陶瓷
·
光学材料
·
激光技术
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Jingxian Yang,Xiaoyan Shu,Fen Luo,Lan Wang,Yucheng Gu,Jianjun Wu,Xirui Lu
The disposal of strontium (Sr) from nuclear reactions has been a great challenge in the nuclear industry. Based on four kinds of occupation methods, a series of SrO-doped Gd 2 Zr 2 O 7 compositions with the general formula Gd 2-2 x /3 Sr x Zr 2 O 7 , Gd 2 Zr 2- x /2 Sr x O 7 , Gd 2- x Sr x Zr 2 O 7- x /2 and Gd 2 Zr 2- x Sr x O 7- x (0.0 ≤ x ≤ 2.0) were prepared by a high temperature sintering method solid state route. The influences of Sr substitution on the structure modifications, solid nuclear mobility, microstructure, and element distribution were studied. Our results show that the four sets of samples reach the maximum solid solubility within the range of x > 2.0, 1.5 < x ≤ 2.0, 1.0 < x ≤ 1.5, 1.0 < x ≤ 1.5, respectively. It was found out that the compound phase of SrZrO 3 and pyrochlore appeared in all the samples. In addition, the amount of the SrZrO 3 increases while the amount of the pyrochlore decrease and that of Sr 2+ increases.
研究领域:
材料科学
·
核废料管理
·
陶瓷
·
固态化学
✓ 已验证
DOI
高影响因子
SCRIPTA MATERIALIA
·
2018
·
IF 4.163
Lili Guan,Jian Li,Xiwen Song,Jinxiao Bao,Tao Jiang
Flash sintering of Sm 2 O 3 doped CeO 2 ceramics can be triggered at 25 °C due to the presence of graphite. The current density rise non-linearly to a set limit value in the voltage control stage under an initial electric field of 30 V cm −1 . The calculated conductivity activation energy in this stage is 0.30 eV, which is closely in relation to the electronic conduction of graphite. As graphite is beginning to oxidize, the conductivity of the sample rapidly decreases. While graphite has been completely oxidized, the specimen temperature provides adequate support for the persistence of flash sintering process .
研究领域:
材料科学
·
陶瓷
·
固体离子学
·
电场辅助烧结
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·Vol. 47
·期 18
·26310-26318
·
IF 4.527
Hao Liu,Chuang Jie,Zhongzhuang Zhang,Zhoufu Wang,Yan Ma,Xitang Wang,Honghong Wang,Ke Wu,Guoqiang Zheng
A study of magnesia refractories containing glucose, citric acid, and metallic Al and their influences on structure, mechanical strength , and thermal shock resistance , is presented. Combined with thermodynamic calculation, microstructure, and properties analysis, the results show that formation of gluconates and citrates from the introduced glucose and citric acid enhanced the bonding of raw materials and the curing strength of samples. The pyrolysis of gluconates and citrates, and the oxidation and nitridation of metallic Al had significant effects on the microstructural evolution of magnesia refractories after high temperature treatments, mainly AlN and MgAl 2 O 4 whiskers in pores and particle gaps. The formation and development of whiskers give rise to samples improved toughness and thermal shock resistance. Increasing the metallic Al content from 0 wt% to 2 wt% enhanced the fracture surface energy of samples heat treated at 1400 °C from 82.22 kJ/m 2 to 119.75 kJ/m 2 . Meanwhile, after three thermal-shock cycles, the residual strength ratios of heat treated samples were elevated from 52.8% to 67.9%. On the basis of influences of phase transformation on the structure and properties of samples at different temperatures, considering the structural compactness and ability to withstand external stress for magnesia refractories used in metallurgical field, it is suggested that when glucose and citric acid are used as binders, the addition of metallic Al should be less than 3 wt%.
研究领域:
材料科学
·
陶瓷
·
耐火材料
·
热力学
·
微观结构分析
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·Vol. 45
·期 1
·116855
·
IF 5.8
Jintao Zhang,Shuai Xu,Chunmei Wen,Jiale Huang,Jiaqi Li,Zhongzheng Wu,Renda Wang,Fangfang Ge,Gaowei Zhang,Zhongqiang Fang,Jun Li,Tongmin Zhang,Xuan Meng,Bingsheng Li
High-entropy carbide ceramics (Ti 0.25 Zr 0.25 Nb 0.25 Ta 0.25 )C with a single-phase rock-salt structure were prepared by hot-pressed sintering. These ceramics were irradiated with 500 keV He 2+ ions to fluences of 5 × 10 16 ions·cm −2 and 1 × 10 17 ions·cm −2 at room temperature to 700 °C. The investigation into irradiation-induced lattice swelling was conducted using grazing incident X-ray diffraction, while microstructure evolution was characterized through transmission electron microscopy . Lattice expansion induced by the He ion irradiation was identified, which highly depends on the irradiation temperature and fluence. Notably, the lattice expansion diminishes with rising irradiation temperature primarily as a result of the dynamic annealing effect . Nano-sized He bubbles , with an average diameter of less than 1 nm were uniformly dispersed within the grain interior. Notably, He bubble nucleation does not exhibit a preference for grain boundaries at 700 °C irradiation. Following He ion irradiation at 350 °C and 700 °C, dislocation loops of 1/3<111> and 1/2<110> with sizes in the ranges of several nanometers were observed. The present study provides insights into high-entropy carbide ceramics with potential applications in the field of nuclear energy.
研究领域:
材料科学
·
核材料
·
辐照损伤
·
陶瓷
·
微观结构表征
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2012
·Vol. 39
·期 3
·2267-2274
·
IF 1.751
Rujie He,Ping Hu,Xinghong Zhang,Wenbo Han,Chuncheng Wei,Yang Hou
PEI was used as dispersant for ZrB 2 and SiC powders in water. The dispersion behavior of ZrB 2 and SiC in water was studied by zeta potential measurements , particle size distribution measurements and interparticle interaction calculations. Well-dispersed ZrB 2 and SiC aqueous suspensions were obtained using 0.6 wt% PEI at pH 6. The rheological behavior of ZrB 2 –SiC aqueous suspensions was also investigated. Finally, a high solid loading (52 vol%), low viscosity (980 mPa s at 100 s −1 ) ZrB 2 –SiC aqueous suspension was successfully prepared.
研究领域:
材料科学
·
陶瓷
·
胶体与界面科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·Vol. 48
·期 12
·16839-16844
·
IF 5.532
Xu Wang,Lei Zhang,Yaqi Ji,Jian Chu,Pengfei Pan,Sheqi Pan,Honglong Wang,Ling Wang,Ming Zhang
In this work, the effects of starting oxide powders with different-scale particle sizes on the synthesis of gadolinium zirconate pyrochlore (Gd 2 Zr 2 O 7 , GZO) and its physical properties were studied. Micron Gd 2 O 3 (μG), micron ZrO 2 (μZ), nano Gd 2 O 3 (nG), and nano ZrO 2 (nZ) powders were used. GZO ceramics were prepared by employing solid-state reactive sintering at 1300 °C, 1400 °C, 1500 °C and 1600 °C with mixed powders of different sizes (μGμZ, μGnZ, nGμZ and nGnZ). X-ray diffraction and Raman analyses of the ceramics revealed that nG has a more significant impact on the crystallization process than nZ. All ceramics synthesized with different sized oxide powders crystallized into pyrochlore phases except for those synthesized with μGnZ mixed powders, which resulted in a fluorite phase. The results indicated that decreasing the particle size of only ZrO 2 to synthesize pyrochlore-phase Gd 2 Zr 2 O 7 with high crystallinity may not be effective. Samples obtained at 1500 °C were further analyzed. Scanning electron microscopy results revealed that all four ceramics have a non-homogeneous grain size and that the average grain size ranges from 5.40 to 8.30 μm. In addition, the density and Vickers hardness measurements showed that the use of nanopowders significantly improves the mechanical properties.
研究领域:
材料科学
·
陶瓷
·
固态化学
·
粉末冶金
·
热处理
✓ 已验证
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2019
·
IF 2.291
Lulu Huang,Jun Guo,Zhen-Hua Ge,Yehua Jiang,Jing Feng
The In 2 O 3 (ZnO) 3 + x mol%Ga 2 O 3 ( x = 0, 0.1, 0.3, 0.5, 1) ceramics were synthesized by a solid-state reaction process. The effect of Ga doping on the thermoelectric properties of the In 2 O 3 (ZnO) 3 ceramics was studied. The phase structure and microstructure of all the bulk samples were checked by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. Additionally, the minimum thermal conductivity of 1.45 Wm −1 K −1 at 973 K is obtained for 0.5% Ga-doped sample, which is 35% lower than that of the pristine sample. The significantly decreased thermal conductivity for Ga 2 O 3 -doped sample is due to the enhanced scattering of phonons , which is derives from the point defects caused by Ga-doping and the introduction of the second phase. As a result, the In 2 O 3 (ZnO) 3 +0.5 mol% Ga 2 O 3 sample achieved the highest ZT value of 0.23 at 973 K.
研究领域:
材料科学
·
热电学
·
陶瓷
·
固态化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·Vol. 50
·期 9
·15172-15181
·
IF 5.1
Shan Gao,Peng Yang,Xinjian Li,Wenting Ji,Haidong Yu,Yaqi Chen,Yuewen Zhang,Hongan Ma,Xiaopeng Jia
SrTiO 3 (STO) is considered a promising high-temperature N-type thermoelectric material . However, its intrinsic insulating properties and high thermal conductivity limit the dimensionless quality factor (zT) due to its simple crystal structure and the existence of light elements. Along these lines, in this work, the optimization of the thermoelectric properties of STO-based materials was achieved by using the high temperature and high pressure (HPHT) method and adjusting the doping ratios of the La and Nb heavy elements . To enhance the doping effect, oxygen vacancies need to be formed within the sample. For this reason, titanium powder was added to the sample. Due to the confined environment induced by the high pressure, which can be attributed to the application of the HPHT method and the strong oxygen trapping ability of Ti at high temperatures, a reducing environment was attained for the samples, the latter, promoted the formation of oxygen vacancies in the synthesized samples, and semiconducting properties were achieved. The thermoelectric properties and microscopic morphology of the synthesized samples with different doping ratios of La and Nb were also thoroughly investigated. Finally, the maximum zT value obtained for the samples was 0.28@973 K. A fast, simple, and effective method for the preparation of oxygen-deficient packet-crystalline oxide materials was developed in this work, which paves the way for significantly improving their thermoelectric properties.
研究领域:
材料科学
·
热电学
·
陶瓷
·
固体物理
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）