MATERIALS CHEMISTRY AND PHYSICS
·
2019
·
IF 2.781
Faqiang Shi,Limeng Liu,Zhaoping Hou,Guihong Geng,Yujin Wang
Tantalum carbide ceramics with an overall composition of TaC 0.6 were prepared by hot pressing at 1700 °C for 1 h under 30 MPa pressure with fcc TaC and bcc Ta powder as starting materials. Effects of adding 0–30 mol% Cu on densification, phase formation, microstructural evolution , mechanical properties and electrical conductivity of the obtained composite ceramics were investigated. Full density could be reached at 20 mol% Cu addition and above. Reactions between TaC and Ta resulted in the final phases of hexagonal Ta 2 C and rhombohedral ζ-Ta 4 C 3-x . Plate-shaped ζ laminate grew in both TaC and Ta 2 C and consequently had their sizes confined by the parental grains. Addition of 20–30 mol% Cu could significantly grow the intermediate Ta 2 C grains, hence controlling length of the ζ laminates precipitated in them to form bimodal microstructures consisting of large grains. The 20 mol% Cu composition had a better flexural strength (706 ± 46 MPa) and fracture toughness (9.2 ± 1.7 MPa m 1/2 ). Electrical resistivity at room temperature of the composites decreased with Cu content from 1.03 μΩ m at 0 mol% addition to 0.12 μΩ m at 30 mol% Cu.
研究领域:
材料科学
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陶瓷学
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复合材料
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粉末冶金
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结构陶瓷
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物理化学
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固态化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Fang Xu,Shuai Xiong,Yan Yang,Hongwei Yang,Yong Ren,Fei Xie,Guixiang Liu,Bo Dai
In this work, LiZnTi ferrites doped with various V 2 O 5 additives were successfully prepared using hot-press sintering. The influences of V 2 O 5 dopant amount and holding time on phase composition, microstructure and gyromagnetic properties of the low-sintered LiZnTi ferrite were studied. Results showed that the grain growth behavior of the LiZnTi ferrites was closely interrelated with dopant amount and holding time as result of changes of critical driving force ( Δg c ). Moreover, the relative density of all the ferrite samples was very high ( ρ r >99 %). However, we found that the longer holding time (can reduce Δg c ), which is benefit for grain growth and improvement of saturation magnetization (4π M s ) of LiZnTi ferrites, resulted in the deterioration of ferromagnetic resonance (FMR) linewidth ( ΔH ) instead. Finally, due to synergistic effect of applied pressure and V 2 O 5 dopant, the LiZnTi ferrite ( x = 0.10) sintered at 900 °C for 10 mins possessed a small average grain size (GS ave. = 0.69 μm ), very high relative density ( ρ r = 99.35 % ) , high saturation magnetization (4π M s = 4193.2 G s) and a relatively low ferromagnetic resonance linewidth ( ΔH = 449.1 Oe).
研究领域:
材料科学
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无机非金属材料
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磁性材料
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电子陶瓷
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功能材料
✓ 已验证
DOI
高影响因子
Journal of Nanomaterials
·
2018
·Vol. 2018
·期 1
·1634814
·
IF 2.207
Lianbing Zhong,Guihong Geng,Yujin Wang,Feng Ye,Limeng Liu
A fully dense TaC ceramic was prepared by hot pressing using 10 mol% ZrC plus 5 mol% Cu as a sintering aid. Formation of (Ta, Zr)C solid solution (ss) by reaction between TaC and ZrC facilitated densification. Addition of Cu refined the microstructure and consequently improved flexural strength of the TaC ceramics. TEM investigation found ubiquitous precipitation of nanocrystallites at multigrain conjunctions. The nanocrystallites were (Ta, Zr)C solid solution with uniform dispersion in an oxygen-rich glassy matrix. Although formation of nanoprecipitates may not much affect the mechanical properties of the TaC ceramic, the structure suggested a new type of nanoceramic worth further research.
研究领域:
材料科学
·
陶瓷学
·
固态化学
·
显微结构分析
·
复合材料
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Liang Zheng,Wenjie Zhang,Qi Wang,Hong Zhang,Zhou Yu,Cuihua Cheng,Yong Zhang,Ming Lei,Yong Zhao
MgB 2 bulks with NaCl doping amount ranging from 0–30 at% have been prepared by hot pressed sintering process . With the increase of NaCl doping amount, the c axis lattice parameter of MgB 2 monotonously increases, indicating the substitution of Mg atoms by larger Na atoms. Meanwhile, the intensity of diffraction peaks of both NaCl and impurity phase of MgO increases. More compact morphology was found in the NaCl doped MgB 2 samples. The critical transition temperature ( T c ) decreases from 38.2 K to 36.8 K with the increase of NaCl doping amount from 0 to 30 at%, and the corresponding transition width of T c (Δ T c ) increases from 0.5 K to 1.8 K. When the doping amount of NaCl is not exceeding 10 at%, the J c value is about 10 6 A/cm 2 at 4.2 K, 3 T, and 5 × 10 5 A/cm 2 at 10 K, 3T. J c performance of the 5 at% NaCl doped MgB 2 sample (NC05) reaches 6.8 × 10 5 A/cm 2 at 20 K, 2T, which improves approximately 20% compared to the pure one, attributing to the better grain connectivity of MgB 2 and enhancement of flux pinning force by NaCl doping.
研究领域:
凝聚态物理
·
材料科学
·
超导材料
·
无机固体化学
·
功能陶瓷
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）