Science China-Technological Sciences
·
2021
·Vol. 64
·期 6
·1250-1263
·
IF 3.572
Liu XiongZhang,Zhang SenJing,Luo Hui,Chen Fu,Li DongMeng,Wang Xian,Gong RongZhou
The design of the high-temperature microwave absorbing materials (MAMs) with temperature-insensitive and considerable microwave absorption (MA) capacity is a tremendous challenge. TiB 2 -Al 2 O 3 /MgAl 2 O 4 MAMs are prepared by the spark plasma sintering (SPS). Further, the influences of the Al 2 O 3 content on the flexural strength, thermal stability, high-temperature electrical conductivity, dielectric and MA properties are discussed. The results show that the Al 2 O 3 content is associated with flexural strength, high-temperature thermal stability, electrical conductivity, dielectric and MA properties. Meanwhile, the temperature-insensitive and considerable MA properties with the minimum reflection loss (RL min ) ranging from −19.4 to −14.3 dB and the effective absorption bandwidth (EAB, RL<−5 dB) of 3.19–3.55 GHz are attained at 25°C–700°C in 8.2–12.4 GHz as the Al 2 O 3 content increases from 70.6 wt% to 80.6 wt%. This is ascribed to the compensating effect of the positive and negative temperature coefficient materials on the high-temperature electrical conductivity as well as the co-play of the dipolar and interfacial polarization at elevated temperatures. Consequently, TiB 2 -Al 2 O 3 /MgAl 2 O 4 ceramics exhibit the ideal prospect as the high-temperature MAMs.
研究领域:
材料科学
·
电子材料
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2017
·Vol. 100
·期 7
·3099-3107
·
IF 2.841
Xiaorong Zhang,Zhixiao Zhang,Weimin Wang,Junhong Shan,Hongwei Che,Jingbo Mu,Guangsuo Wang
B 4 C–TiB 2 –SiC composites toughened by composite structural toughening phases, which are the units of (TiB 2 –SiC) composite, were fabricated through reactive hot pressing with B 4 C, TiC, and Si as raw materials. The units of (TiB 2 –SiC) composite with the size of 10-20 μm are composed of interlocking TiB 2 and SiC with the size of 1-5 μm. The addition of TiC and Si can effectively promote the sintering of B 4 C ceramics. The relative densities of all the B 4 C composites with different contents of TiB 2 and SiC are close to completely dense (98.9%-99.4%), thereby resulting in superior hardness (33.1-36.2 GPa). With the increase in the content of TiB 2 and SiC, the already improved fracture toughness of the B 4 C composite continuously increases (5.3-6.5 MPa·m 1/2 ), but the flexure strength initially increases and then decreases. When cracks cross the units of the (TiB 2 –SiC) composite, the cracks deflect along the interior boundary of TiB 2 and SiC inside the units. As the crack growth path is lengthened, the crack propagation direction is changed, thereby consuming more crack extension energy. The cumulative contributions improve the fracture toughness of the B 4 C composite. Therefore, the composite structural toughening units of the (TiB 2 –SiC) composite play an important role in reinforcing the fracture toughness of the composites.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Y.M. Zhou,T. Zhang,K. Xu,F.L. Zhang,K. Bai,H.P. Huang,S.H. Wu,S.M. Luo
Owing to great hardness and low friction coefficients on steel, AlMgB 14 has several potential applications in the fields of cutting tools and wear-resistant materials. In the current work, the effect of Y 2 O 3 addition on the mechanical properties and microstructure of spark plasma sintered AlMgB 14 and AlMgB 14 -TiB 2 has been investigated. An increase in the amount of Y 2 O 3 led to an increase in the number of secondary phases including MgAl 2 O 4 and Y 2 O 3 in AlMgB 14 matrix. The addition of Y 2 O 3 led to a refinement in the grain size of AlMgB 14 and AlMgB 14 -TiB 2 ; however, simultaneously increased the porosity. With the addition of 3 wt% Y 2 O 3 , both AlMgB 14 and AlMgB 14 -TiB 2 reached the finest grain size and the highest hardness while maintaining a low porosity.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2021
·
IF 3.383
Yanqing Xue,Bo Li,Xinliang Wang,Xinlei Li,Han Zhang,Qitang Hao
Agglomeration behavior of TiB 2 particles in 5%TiB 2 /Al-4.5%Cu composites (all compositions are in wt.% unless otherwise specified) is studied by adding different content of Mg to improve its strength and ductility, a widely used in-situ molten salt reaction process is used to produce the composites. The results show that addition of Mg could not only significantly segregate TiB 2 particles but also further refine the α-Al grains and then improve the mechanical properties of the composites on the basis of TiB 2 particles. Here, 0.5% Mg is considered the optimum mass fraction for dispersion, refinement, and modification of particles based on the results of investigation. The yield strength (YS), ultimate tensile strength (UTS), elastic Young’s modulus (EM), and Vicker’s hardness (VHN) of the composites in T6 heat treatment are increased to 375 MPa, 486 MPa, 88 GPa, and 167 HV - an improvement of 21.8%, 16.5%, 20.9%, and 9.4%, respectively, versus the original TiB 2 /Al-4.5%Cu composite (308 MPa, 417 MPa, 63 GPa, and 153 HV). The elongation of the composite is improved by 20.9%. These merits are mainly attributed to addition of Mg, which increases the surface-spread coefficient of TiB 2 particles by reducing the surface tension of the Al melt, thereby improving the wettability .
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Lei Yu,Kuibao Zhang,Daimeng Chen,Baozhu Luo
TiB 2 -B 4 C composites modified by SiC W with excellent mechanical properties were prepared using hot-press sintering. The effects of SiC W content on the microstructure, densification behavior and mechanical properties were investigated. The dynamic failure behavior was analyzed through the Hopkinson Bar (SHPB) testing. The results demonstrate that the addition of SiC W can effectively refine the microstructure and simultaneously improve the mechanical properties. The TiB 2 -B 4 C composite renforced with 6 wt% SiC W exhibits a nearly full-dense microstructure and excellent mechanical properties. The relative density, flexural strength , Vickers hardness and fracture toughness can reach to 99.95 %, 724 ± 61 MPa, 19.8 ± 0.7 GPa and 6.7 ± 0.3 MPa m 1/2 , respectively. The dynamic failure behavior exhibits that the damage degree increases with elevated loading speed. Moreover, the single-peak and double-peak of the waveform correspond to the two damage degrees of "broken" and "crushed".
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·Vol. 48
·期 6
·8579-8588
·
IF 4.527
Sunyi Shen,Shaolei Song,Jinming Wang,Rong Li,Xingchao Li,Qiang Zhen
Microstructure control and multiple compounding methods in the synthesis stage can enhance microwave absorption performance of microwave absorbents. In this work, we successfully synthesized binary TiB 2 –SiC (TsBC) powders with hexagonal sheet (TiB 2 ) and particle (SiC) interlocking structures by sol-gel carbothermal reduction method. We investigated the effect of raw material ratio and synthesis temperature on the synthesized powders and evaluated the microwave absorption properties of the synthesized TsBC powders. It was found that the TsBC absorber exhibited excellent microwave adsorption properties with the minimum Reflection Loss ( R L ) reached −21.8 dB at 17.4 GHz corresponding to the thickness of 4 mm. This excellent performance was attributed to the interfacial polarization between TiB 2 –SiC interfaces and the multiple reflections between the sheet-particle interlocking structures.
研究领域:
材料科学
·
功能材料
·
复合材料
·
电磁学
·
无机非金属材料
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Pei Feng,Hanjun Wei,Jimei Xue,Yuhua Shi,Peng Shang,Wenyuan Zhang,Sihai Luo,Xiaoqing Liang,Weifeng He
A designed conductive nanoheterogeneous structure can boost interfacial polarisation and effectively enhance the wave absorption properties. Herein, maze-shaped nanoheterogeneous TiB 2 -SiCnws-SiOC ceramics were synthesised via a polymer-derived ceramics (PDCs) approach for constructing a three-dimensional reticular structure. The addition of TiB 2 not only compensates for the lower conductivity, but also facilitates the growth of curved SiCnws. The results show that the addition of 20 wt% TiB 2 leads to favourable microwave absorption performance, with a minimal reflection coefficient of − 55.1 dB at 8.9 GHz and an effective absorption bandwidth of 4.2 GHz. This can be ascribed to the synergistic effect among polarisation loss, conduction loss, and microwave multiple reflection and scattering due to the unique structure. This study may contribute towards establishing multi-loss mechanisms and controllable dielectric properties in PDCs.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yingjie Shi,Weixing Li,Xiaorong Zhang,Wenjie Yang,Jingbo Mu,Yu Dong,Hongwei Che,Yanming Wang,Yafeng Wang,Zhixiao Zhang
Core–shell structural B 4 C@TiB 2 composite powders were synthesized via the molten salt method using micron-sized B 4 C and TiH 2 powders as raw materials. Furthermore, a SiC composite ceramic with B 4 C@TiB 2 core–shell structural units as the toughening phase was prepared by spark plasma sintering using SiC powder and the obtained B 4 C@TiB 2 composite powder as starting powders. The effects of calcination temperature and raw material ratio on the phase compositions and microstructure of the B 4 C@TiB 2 composite powders were studied, and the synthesis mechanism of the B 4 C@TiB 2 composite powder was explored. The formation mechanism of B 4 C@TiB 2 core–shell toughening units inside the SiC matrix was investigated, and the toughening mechanism of the SiC–B 4 C@TiB 2 composite ceramic was discussed. Results show that the B 4 C@TiB 2 core–shell units in the SiC matrix can induce a complex crack propagation mode and consume abundant crack propagation energy. Therefore, a high fracture toughness of 6.47 ± 0.32 MPa m 1/2 is realized for the SiC–B 4 C@TiB 2 composite ceramics.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Jiaji Yang,Xiongzhang Liu,Wei Gong,Tao Wang,Xian Wang,Rongzhou Gong
Developing high-temperature microwave absorption (MA) materials remains a challenge in the field of radar stealth. Here, we propose a design concept of meta-structure for temperature-insensitive and broadband MA. The three-phase TiB 2 /Al 2 O 3 /MgAl 2 O 4 composites are prepared to realize the temperature-insensitive MA properties, which is ascribed to the interaction of different components in terms of the electrical conductivity , dipolar polarization and interfacial polarization as temperature increases. On this basis, we design and fabricate a three-layer meta-structure composed of the SiO 2 ceramics as environmental adaptation layer, the patch-type and flat composites as MA layers. Compared with flat composites, the meta-structure can optimize its effective permittivity, thereby realizing enhanced MA properties at elevated temperatures. This meta-structure can realize a reflection loss (RL) less than −5 dB at 8.2–18.0 GHz in the temperature range of 25 °C to 1100 °C. The experiment matches well with the simulation. The temperature-insensitive and enhanced MA properties are attributed to the consequence of the combination of traditional absorbing materials and metamaterial structures.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS & DESIGN
·
2018
·
IF 4.525
Changcong Wang,Kezhi Li,Qinchuan He,Caixia Huo,Xiaohong Shi
A combined heterogeneous coating composed of LaB 6 -MoSi 2 -TiB 2 (LMT) outer layer and SiC inner layer was fabricated on carbon/carbon (C/C) composites using a two-step method. Among them, the SiC transition layer was in-situ synthesized by pack cementation (PC) in the first step, where-after supersonic atmospheric plasma spraying (SAPS) was devoted to deposit the LMT outer layer. The combined LMT/SiC coating revealed a representative microstructure with limited porosity and adhered well with the C/C substrate. Isothermal oxidation test demonstrated that the combined LMT/SiC coating displayed a better oxidation resistance than the MoSi 2 /SiC coating without the addition of rare-earth La and alloying Ti elements at 1773 K. Oxyacetylene torch experiment showed that the combined LMT/SiC coating could efficiently protect the C/C composites withstand short-term ablation for 60 s. The good oxidation and ablation resistant properties of the combined LMT/SiC coating were ascribed to the integrity of LMT/SiC coating and superior protection of a glassy La-Si-O-B-Ti compound scale formation during oxidation and ablation.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
Science China-Technological Sciences
·
2021
·Vol. 64
·期 6
·1264-1275
·
IF 3.572
Liu XiongZhang,Luo Hui,Li YinRui,Chen Fu,Liu JieLing,Yang WenTao,Wang Xian,Gong RongZhou
TiB 2 /Al 2 O 3 ceramics reinforced with MgO are prepared by spark plasma sintering (SPS). The dielectric and microwave (MW) absorption properties are discussed. The results indicate that both the commercial TiB 2 (C-TiB 2 ) content and preparing temperature play important roles in the dielectric properties. Simultaneously, TiB 2 /Al 2 O 3 composite shows the best MW absorption property when the C-TiB 2 content and preparing temperature are 9 wt% and 1400°C. To further improve the MW absorption properties, the composite containing 9 wt% synthesized TiB 2 (S-TiB 2 ) has been sintered at 1400°C. Its high-temperature complex permittivity is greater than that of TiB 2 /Al 2 O 3 composite with 9 wt% C-TiB 2 sintered at 1400°C and is directly proportional to the temperature. Besides, TiB 2 /Al 2 O 3 composite with 9 wt% S-TiB 2 possesses a better MW absorption at 25–500°C, its effective absorption bandwidth ( RL <−5 dB) can reach 4.2 GHz at 25–500°C. And the minimum reflection loss ( RL min ) value reaches −43.41 dB at the temperature of 800°C with a thickness of 1.45 mm for TiB 2 /Al 2 O 3 composite with 9 wt% C-TiB 2 . Consequently, the satisfying absorbing layer ( d <1.75 mm), flexural strength, heat stability and considerable high-temperature MW absorption ability grant TiB 2 /Al 2 O 3 ceramics practical applications as high-temperature microwave absorption materials (MAMs).
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Xiongzhang Liu,Hui Luo,Jiaji Yang,Xian Wang,Zewen Qu,Heng Luo,Rongzhou Gong
TiB 2 –MgO microwave absorbing materials with TiB 2 as the absorber, MgO as the matrix are prepared by spark plasma sintering (SPS). The influences of commercial TiB 2 content and sintering temperature on dielectric and microwave absorption (MA) properties are studied. Besides, to optimize the MA performance, TiB 2 –MgO composite containing TiB 2 synthesized by the carbonthermal process is prepared. Meanwhile, its high-temperature dielectric and MA properties are investigated. Indeed, both the commercial TiB 2 content and sintering temperature play key roles in dielectric and MA properties, as they reaching 8 wt% and 1400 °C, the composite presents the optimal MA performance. For composite with synthetic TiB 2 as the absorber, the temperature has a positive effect on dielectric and MA properties. The enhanced high-temperature MA properties with minimum reflection loss ( RL min ) of −52.11 dB at 1.6 mm under 500 °C and effective absorption bandwidth (EAB, RL < −5 dB) of 4.2 GHz at 1.4–1.6 mm under 800 °C are obtained, which is mainly attributed to the temperature-dependent interfacial polarization compared to the temperature-insensitive conductivity. The excellent mechanical properties (flexural strength = 212.48 MPa), thin absorbing layer (d < 2 mm), enhanced thermal stability and high-temperature MA properties indicate that the TiB 2 –MgO composites can be considered as new candidates for high-temperature structure microwave absorbing materials.
研究领域:
材料科学
·
电磁学
✓ 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）