JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2020
·
IF 4.495
Lu Zhu,Xuanru Ren,Xiaohong Wang,Xueqin Kang,Ruixin Zheng,Peizhong Feng
Spent MoSi 2 heating elements, which worked in the industrial electrical furnace at high temperature, were crushed into powders and reused as coating raw materials. ZrO 2 was added into spent MoSi 2 powders to fabricate MoSi 2 -ZrO 2 coatings on niobium by spark plasma sintering, and the microstructure and oxidation behavior of the coatings at 1500 and 1700 °C were explored. The results showed that cracks exist in MoSi 2 coating while ZrO 2 -containing coatings are crack-free with the formation of (Mo,Nb) 5 Si 3 diffusion layer after SPS, indicating good metallurgical bonding. After oxidation at 1500 °C for 20 h, the lowest mass gain is obtained by MoSi 2 -30ZrO 2 coating. SiO 2 and ZrSiO 4 are formed on the composite coatings at elevated temperature, which improves the high-temperature oxidation resistance. After oxidation at 1700 °C for 60 min, the oxide scale of MoSi 2 -30ZrO 2 coating is dense without any voids or cracks, demonstrating better high-temperature oxidation resistance than that of single MoSi 2 coating.
研究领域:
材料科学
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高温材料
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涂层技术
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2016
·Vol. 99
·期 4
·1147-1150
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IF 2.787
Gaoming Zhu,Xiaohong Wang,Peizhong Feng,Zhangsheng Liu,Jinan Niu,Farid Akhtar
MoB and SiC particulate reinforced MoSi 2 matrix composites were synthesized in situ from Mo, Si, and B 4 C powder mixtures by self-propagating high-temperature synthesis (SHS). The SHS MoSi 2 –MoB–SiC products were vacuum hot-pressed (HPed) at 1400°C for 90 min to fabricate high-density (> 97.5% relative density) bulk composites. Microstructure refinement and improvements in the Vickers hardness and fracture toughness of the HPed composites were observed with increasing B 4 C content in the reaction mixture. The HPed composite of composition MoSi 2 –0.4MoB–0.1SiC exhibited grain size of 1–5 μm, Vickers hardness of 12.5 GPa, bending strength of 537 MPa, and fracture toughness of 3.8 MPa.m 1/2 . These excellent mechanical properties indicate that MoB and SiC particulate reinforced MoSi 2 composites could be promising candidates for structural applications.
研究领域:
材料科学
·
陶瓷材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE CERAMIC SOCIETY OF JAPAN
·
2018
·Vol. 126
·期 7
·504-509
·
IF 0.887
Zhiwu JIANG,Peizhong FENG,Xiaohong WANG,Hanzhu ZHANG,Yanan LIU
MoSi2–ZrB2–SiC ceramics were synthesized using Mo, Zr, Si and B4C powders by self-propagating high-temperature synthesis and densifying by spark plasma sintering. The effects of MoSi2 content on the combustion synthesis process, microstructure, and mechanical properties of the ceramics were investigated. The results showed that combustion synthesis is an unstable mode, spiral combustion. The Gibbs calculations and combustion temperature curves indicate there are two reactions occurring at the same time. The volume fraction of the four different phases and their relative densities were also measured and calculated. Compared to pure MoSi2, the 1.0MoSi2–0.2ZrB2–0.1SiC (M10) ceramic exhibits excellent mechanical properties with its maximum Vickers hardness and fracture toughness being 14.0 GPa and of 5.5 MPa m1/2, respectively. The hardness is in agreement with the rule of mixture. The morphology of indentation cracks reveals that the fracture toughness improves as a result of toughening mechanisms such as crack bridge, crack deflection, and microcracks.
研究领域:
材料科学
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHARACTERIZATION
·
2022
·
IF 4.537
Jianjun Zhang,Ziqiao Wang,Jiajun Luo,Subin Wang,Bingliang Liang,Weihua Chen
MoSi 2 is the most potential high temperature structural materials that can be used in aerospace and aviation industry. But its fracture toughness is low and its low temperature oxidation resistance is poor, which limits its application. To solve these problems, novel MoSi 2 @ZrO 2 core-shell composites were prepared by spark plasma sintering (SPS) at 1300 °C⁓1500 °C. The influences of sintering temperatures on the microstructures, mechanical properties and tribological properties of the composites were studied. It was found that the relative density, Vickers hardness , bending strength and fracture toughness of the composites first ascended and then descended with the sintering temperature rising from 1300 °C to 1500 °C. As the sintering temperature reached 1400 °C, the maximum relative density, the maximum Vickers hardness , the maximum bending strength and the maximum fracture toughness of the composite material achieved 97.5%, 1103 HV, 540 MPa and 7.96 MPa·m 1/2 , respectively. Additionally, the friction coefficient of the composite materials first descended and then ascended with sintering temperature rising. As the sintering temperature reached 1400 °C, the minimum friction coefficient was about 0.355. Moreover, we analyzed the relations between the mechanical properties and microstructure. The toughening mechanisms of the MoSi 2 @ZrO 2 composites were also discussed. In addition, during cyclic isothermal oxidation at below 600 °C, weight gains of the MoSi 2 @ZrO 2 composites evidently decreased, compared with that of pure MoSi 2 , proving better low-temperature oxidation resistance .
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
Journal of Materials Chemistry A
·
2019
·Vol. 8
·期 1
·259-267
·
IF 10.733
Congcong Dang,Yu Wang,Biao He,Weibin Zhang,Feng Dang,Hongchao Wang,Yong Du
Searching for highly efficient and low cost electrocatalysts is an urgent challenge to provide high capacity and long cycle life Li–O2 batteries (LOBs). In this work, the highly efficient electrocatalytic properties of MoSi2 were first demonstrated using particles prepared by a solid–state reaction method. The surface was activated, playing a dominant role in the electrocatalytic performance. After acid etching to remove SiO2 impurities arising from the surface oxidation, MoSi2 exhibited excellent bifunctional electrocatalytic properties for LOBs. Mo6+ on the surface contributed to the initial low overpotentials of 0.45 V (3.2 V for the OER and 2.75 V for the ORR) and transformed into Mo4+ for a long cycle life. As a consequence, outstanding rate capabilities of 12 708 mA h g−1 at 100 mA g−1 and 10 794 mA h g−1 at 800 mA g−1, and excellent cycle durability of 215 and 90 cycles at a limited capacity of 1000 mA h g−1 at 200 and 500 mA g−1, respectively, were obtained for the MoSi2 cathode.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
Advances in Applied Ceramics
·
2019
·
IF 1.429
Guangyuan Yang,Sanwen Peng,Zheming Li,Zhixiong Huang
Carbon fibres (CF) have been used in various fields because of their unique properties. However, the oxidation resistance ability of CF is not good enough. The paper discusses the issue of using composite plating method to deposit SiC–MoSi2–ZrO2 coating at the surface of CF. The plating factors, including nanoparticle concentration, plating bath temperature, current density, agitation rate and electroplating time, which affect the structure and performance of coating have been discussed. The energy dispersive spectrometer has been applied to test the mass fraction of nanoparticles in the coating. Also, the surface morphology of coated CF has been characterised by a scanning electron microscope and the antioxidation ability of each sample has been tested by the weight difference method. The results indicate that with the proper plating factors, the coating can improve the antioxidation performance of CF and its reinforced composites. The residual weight of coated CF is over 52% after 1400°C oxidation for 15 min.
研究领域:
材料科学
·
表面工程
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2020
·
IF 3.408
Si Li,Dakui Zhao,Huili Wang,Yu Zhang,Wenjiang Huang,Ying Zhou
The valence electron structure (VES) of MoSi 2 -based solid solution alloys was studied herein by the bond length difference (BLD) method based on the empirical electron theory (EET) of solids and molecules and the average atomic model. Compared to those for a MoSi 2 alloyed with Al or Mg separately, alloying with Mg + Al together significantly decreased the bond energy of the main bond branch and the ratio of the number of covalent valence electrons to the total number of valence electrons in the Mo(Si 0.92 Al x Mg 0.08- x ) 2 solid solutions and increased the lattice electrons. Thus, alloying MoSi 2 with Mg + Al together reduced the hardness and strength of MoSi 2 and increased its fracture toughness above what occurred when Mg or Al were added separately. The combined impact of the impurities was especially noticeable when MoSi 2 was alloyed with 4 at% Mg+4 at% Al. Based on those results, Mo(Si 0.92 Al x Mg 0.08- x ) 2 solid solution alloys were made, their mechanical properties were tested, and the experimental results were consistent with those of the theory.
研究领域:
材料科学
·
固体力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2019
·
IF 4.029
Jia-Qi Zheng,Jian Chen,Bu-Hao Zhang,Xue-Jian Liu,Zhong-Ming Chen,Hai-Bo Wu,Zheng-Ren Huang
SiC-MoSi 2 composites with low electrical resistivity and high infrared emissivity were fabricated via pressureless sintering. The relationship between microstructure evolution and electrical behaviors along with infrared emission properties of the resulting composites is investigated at various sintering temperatures . The electrical resistivity undergoes two significant drops with increasing sintering temperature. Pore elimination bears responsible for the initial decrease in electrical resistivity. Transmission electron microscopy (TEM) observation manifests that the thinned amorphous layers at SiC/MoSi 2 interface decrease grain boundary resistivity and allow for electrical percolation to occur when sintering temperature further rises. Additionally, increasing sintering temperature leads to a higher infrared emissivity owing to the formation of Mo 4.8 Si 3 C 0.6 and the decreased boundaries. The lowest electrical resistivity of 7.2 Ω cm and the highest infrared emissivity of 0.721 are recorded for composite sintered at 2000 ℃. Overall, SiC-MoSi 2 composites exhibit a promising prospect as infrared source elements that must endure harsh environments.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Guangyuan Yang,Xu Wang,Zhixiong Huang
To improve the oxidation resistance ability of carbon fiber (CF) in the high temperature environment, the composite electroplating method had been used to fabricate SiC-ZrO-MoSi 2 /Ni coating at the surface of CF. Both nanoparticles and Ni-matrix were plated onto CF successfully while the mechanical property of coated CF was only slightly weakened. The oxidation resistance performance of CF and the CF reinforced phenolic resin composites had been improved obviously. The microstructure of coatings was investigated by scanning electron microscope and X-ray diffraction analysis. Thermal gravimetric analysis was applied to test the anti-oxidation ability of coated CF. The mechanism of oxidation process had been discussed. It can be concluded that composite plating is an effective way to make composite coatings which can enhance the anti-oxidation ability of CF.
研究领域:
材料科学
·
表面工程
✓ 已验证
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
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Mingcheng Zhu,Lan Zhang,Na Li,Desen Cheng,Jidong Zhang,Shiyao Yu,Hui Bai,Huizhong Ma
Ternary ZrB 2 –SiC–MoSi 2 composites with different nominal volume fractions of SiC (10–25 vol%) and MoSi 2 (5–20 vol%) were sintered by reactive spark plasma sintering (RSPS) at 1650 °C and 35 MPa from the starting powders of ZrB 2 , Si, Mo and activated charcoal. The densification behaviour, microstructures and mechanical properties were comprehensively investigated. SiC clusters and MoSi 2 were formed by in-situ reactions and the improved sintering efficiency was attributed to the mass transfer by liquid Si. The formation of a core–shell (Zr, Mo)B 2 solid solution was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). With the addition of the nominal MoSi 2 content up to 15 vol%, the molar ratio of MoB 2 in the solid solution shell increased owing to the increase of Mo; the densification and mechanical properties decreased owing to the softness of MoSi 2 , the cracks, and the large size of SiC clusters. The relative density, Vickers hardness , and fracture toughness of ZrB 2 –SiC–MoSi 2 composites were significantly better than those of bulk ZrB 2 owing to the combined effect of phase enhancement and solid solution strengthening.
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
JOURNAL OF REINFORCED PLASTICS AND COMPOSITES
·
2024
·
IF 2.3
Qiang Shen,Suohui Yang,Shiquan Zhang,Sheng Hu,Junguo Li,Jian Zhang
Ceramizable phenolic resin matrix composites have a significant potential for widespread applications in the field of aerospace ablation. However, due to the sharp decrease of mechanical properties at elevated temperatures, the composite fails to meet the requirements of thermal protection as well as load-bearing of aircraft in a wide temperature range. In this study, boron phenolic composites modified by MoSi2 and SiB6 with high strength in a wide temperature range are prepared. The flexural strength of composites after ablation within the temperature range of 800 °C to 1600 °C ranges from 48.07 to 82.49 MPa. In particular, a significant increase of 224.9% is obtained at 1400 °C with 6 wt% SiB6. The mass ablation rate and line ablation rate of the composites are increased to 0.054 g/s and 0.013 mm/s, respectively. The cooperation effect of oxygen consumption, carbon fixation, oxygen barrier, and liquid phase bonding produced by ceramization reactions involving SiB6, MoSi2, O2, and pyrolytic carbon at different temperatures, resulting in an improvement of the mechanical property and the oxidation resistance of the composite. These composites have a potential in long term thermal protection and load-bearing of new ablation materials.
研究领域:
航空航天材料
·
高温材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）