JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Weide Wang,Dongxu Yao,Hanqin Liang,Yongfeng Xia,Kaihui Zuo,Jinwei Yin,Yu-Ping Zeng
This work reports the two-step sintering method and thermal conductivity of Si 3 N 4 doped with 1.5 wt% MgO and varied contents of ZrH 2 in the range of 0-5 wt%. The metal hydride reduction reaction in the first step sintering allows the in situ generations of ZrO 2 and the elimination of native SiO 2 . A smaller amount of liquid phase with reduced oxygen content was produced during the second step sintering as a result of the replacement of ZrO 2 by ZrH 2 . With the aid of ZrH 2 as an oxygen getter, the native oxygen in those ZrH 2 -doped samples was removed via a route of SiO 2 →ZrO 2 →SiO(g). Consequently, the densified Si 3 N 4 ceramics with larger volume percent of elongated purified β-Si 3 N 4 grains and less glassy phase were obtained. Ultimately, the optimal thermal conductivity of 116.4 W m −1 K −1 was achieved after sintered at 1900 °C for 12 h by using 3 wt% ZrH 2 and 1.5 wt% MgO as additives.
研究领域:
材料科学
·
热物理
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2017
·
IF 3.663
Yanjing Yang,Fengqi Zhao,Huixiang Xu,Qing Pei,Hanyu Jiang,Jianhua Yi,Chunlei Xuan,Sanping Chen
The reaction mechanisms of metal hydrides in the combustion of solid propellants are closely related to their effects on the energetic and combustion properties of propellants. Here, we report a first attempt to investigate the reaction mechanisms of ZrH 2 , a promising candidate for fuels, in the combustion of HTPB propellants using ammonium perchlorate (NH 4 ClO 4 , AP) as the oxidizer . ZrH 2 is determined to possess a good resistance to the direct oxidation by AP. Thus, it would dehydrogenate independently to generate H 2 and metallic Zr , which is believed to be very favorable for decreasing the gaseous molecular masses . On the other hand, due to the attachment of gaseous reactants to it, ZrH 2 was found to tune the decomposition behaviors of AP by enhancing the generation of NO in the high-temperature decomposition stage. More interestingly, the hydrogen released from ZrH 2 is evaluated to promote the combustion reactions in gaseous phases and be responsible for the two-stage combustion behaviors of the corresponding propellant, which are distinct from those when metallic Al is used as the fuel. The findings in this work validate the potential of ZrH 2 as a fuel for high-energy solid propellants.
研究领域:
推进剂化学
·
燃烧科学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2017
·
IF 3.454
Mingyu Xiang,Jingjing Xie,Wei Ji,Hang Ping,Weimin Wang,Hao Wang,Jinyong Zhan,Yan Xiong,Zhengyi Fu
Zirconium carbide (ZrC 0.84 O 0.13 ) nanopowders were consolidated using plasma activated sintering with 0–8 wt% ZrH 2 as the sintering additive to improve the sinterability. Compared with pure ZrC sintering, ZrH 2 additive led to the higher sintering kinetics and lower sintering temperature . This improvement was attributed to the increased carbon-vacancy concentration in the non-stoichiometric ZrC in the presence of ZrH 2 additive during the sintering process. Fully dense and fine-grained ZrC ceramics (1.3 ± 0.2 μm) were achieved at 1650 °C with 6 wt.% ZrH 2 . The final product exhibited the Vicker’s hardness of 21.2 ± 1.0 GPa and fracture toughness of 2.2 ± 0.3 MPa m 1/2 .
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 Central South University
·
2023
·Vol. 30
·期 5
·1512-1522
·
IF 4.4
Dong Zhao-wang,Duan Liang-hong,Liu Han-ning,Guo Xue-yi,Xia Yang
High-purity zirconium metal has been of rising significance to the nuclear and energy industry. However, zirconium exhibits a strong chemical affinity to oxygen, which causes high-purity zirconium metal to be difficult to produce cost-effectively. Powder metallurgy for preparing zirconium metal can achieve near net forming of zirconium metal. Zirconium powder can be prepared by deoxidation of zirconium hydride powder. In this study, an efficient process was proposed to prepare high-purity ZrH 2 using magnesium powder as reducing agent in hydrogen atmosphere. A specific investigation was conducted on the effect of hydrogen on the magnesiothermic reduction and deoxidation of ZrO 2 . As indicated from the results, the oxygen content of the reduced powder in Ar was over three times that in H 2 atmosphere at 750 °C for 240 min. Moreover, a passive oxide layer, with a thickness of ~2.76 nm in H 2 and of ~8.51 nm in argon, was formed on the edge of the reduced powder. In accordance with thermodynamic calculation, hydrogen was found to be capable of destabilizing Zr-O solution. An ultra-high pure zirconium hydride powder containing <350×10 −6 oxygen and particle size of <100 µm was prepared as assisted by hydrogen.
研究领域:
材料科学
·
核能工程
·
粉末冶金
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2023
·Vol. 12
·期 4
·2423-2434
·
IF 11.9
Lingchao Zhang,Xin Zhang,Wenxuan Zhang,Fang Fang,Juan Li,Jianjiang Hu,Changdong Gu,Wenping Sun,Mingxia Gao,Hongge Pan,Yongfeng Liu
Catalyst-modified magnesium hydride (MgH2) holds the greatest promise as a solid-state hydrogen storage medium for mobile and stationary applications. However, the design and fabrication of highly active catalysts that enable MgH2 to reversibly desorb/absorb a large amount of hydrogen still remains challenging. In this work, a novel nanostructured ZrFe2 (nano-ZrFe2) measuring 30–120 nm in size was designed and fabricated as a catalyst precursor, which was readily converted into ultrafine ZrH2 and metallic Fe nanoparticles upon ball milling with MgH2 and first de-/hydrogenation, consequently delivering quite high catalytic activity for hydrogen storage in MgH2. MgH2 containing 10 wt% nano-ZrFe2 desorbed 6.2 wt% of H2 starting from approximately 193 °C, which was lowered by 35 °C with respect to the micron-ZrFe2-modified MgH2 (∼228 °C). When operated at a hydrogen pressure of 50 bars, the dehydrogenated sample absorbed ∼5.3 wt% of H2 at 200 °C within 30 minutes. The remarkably improved kinetic properties of MgH2 are mainly attributed to the ultrasmall nanoparticles and uniform, dispersive distribution of in situ formed ZrH2 and Fe. Such in situ conversion of nano-ZrFe2 not only provided a multiphase and multiscale catalytic environment that enabled high reactivity and catalytic activity but also facilitated H diffusion owing to increased interfaces, consequently promoting the dissociation and recombination of H2 molecules. These important insights in the new nanoscaled intermetallics broaden the scope of the design and synthesis of much higher active catalysts for hydrogen storage in light-metal hydrides, especially in MgH2.
研究领域:
材料科学
·
化学工程
·
能源存储
✓ 已验证
DOI
高影响因子
COMBUSTION SCIENCE AND TECHNOLOGY
·
2025
·
IF 1.5
Jinbo Guo,Wenjie Liu,Xiaojuan Fu,Penglin Kang,Wenyu Wu,Fusheng Cui,Xiaodong Li
Metal hydrides are ideal additives for solid propellants, which can improve the energy level and load capacity of solid propellants. However, the safety and interaction mechanisms between metal hydrides and energetic materials remain unclear, which limits their broader application in propellants. In this study, RDX/ZrH2/F2602 energetic composite particles with varying ZrH2 contents were prepared using the molding powder method and subsequently characterized in terms of their performance. The experimental results demonstrate that the energetic composite particles display a regular morphology and dense structure, with no changes observed in their chemical and crystal structures. As the ZrH2 content increases, the thermal stability and thermal explosion critical temperature of the composite particles decrease. In comparison to the raw material RDX, the energetic composite particles with 10% and 15% ZrH2 contents exhibit better mechanical sensitivity, with critical impact values increasing by 6 J and 5.5 J, respectively, and critical friction values increasing by 84 N and 60 N, respectively. Combustion experiments reveal that energetic composite particles containing 15% ZrH2 demonstrate superior comprehensive performance in terms of safety and combustion, outperforming those with other ZrH2 contents. The oxidative combustion mechanism of RDX/ZrH2/F2602 energetic composite Particles is discussed, offering insights into the interaction between metal hydrides and the combustion of energetic materials. This research establishes a theoretical framework to support the design and improvement of solid propellant formulations.
研究领域:
含能材料
·
推进剂化学
·
燃烧科学
·
材料安全性
·
固体推进剂
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Man Chen,Yiqi Wang,Xuezhang Xiao,Yunhao Lu,Meng Zhang,Jiaguang Zheng,Lixin Chen
Magnesium hydride (MgH 2 ) has attracted extensive attention over the past decades due to its highly reversible hydrogen storage density (7.6 wt%). But intrinsic high activation energy barriers for de/rehydrogenation of MgH 2 /Mg restrict its potential application as an on-board hydrogen carrier. Herein, ZrH 2 nanocatalyst homogeneously distributed on the surfaces of MgH 2 exhibits pronounced low temperature de/rehydrogenation kinetics, resulting from the vast lattice distortions between ZrH 2 and MgH 2 /Mg phases. The ZrH 2 doped MgH 2 composite (MgH 2 -ZrH 2 ) starts to release H 2 at 203 °C, 102 °C lower than that of undoped MgH 2 . Most importantly, MgH 2 -ZrH 2 quickly absorbs 5.90 wt% H 2 at the temperature as low as 65 °C. Further deep investigations found that H atoms preferentially accumulates around ZrH 2 , since the lower hydrogen dissociation energy on the surfaces of ZrH 2 (1.421 eV) than that of pure Mg (2.301 eV). Then, the large lattice disordered zone between ZrH 2 and Mg phases enables H atoms diffuse easily into the lattice of Mg nearby, thus triggering the formation of MgH 2 . These findings are critically important to understand the mechanism of other metal hydride catalysts, as well as offer an opportunity for the practical on-board fuel cell applications in the future.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2022
·
IF 5.767
Hua Fang,Peng Deng,Rui Liu,Kehua Han,Pengfei Zhu,Jianxin Nie,Xueyong Guo
Metal hydride has been used as a potential energetic material due to its high hydrogen storage density, high reactivity, high mass calorific value and large gas production. But it was still a great challenge towards optimizing and enhancing the energy-releasing properties of metal hydride. In this work, a novel molecular perovskite energetic material (H 2 dabco)[NH 4 (ClO 4 ) 3 ] (DAP-4) was introduced as a high energy oxidant to fabricate metal hydride (MH 2 , M=Mg, Ti, and Zr) based energetic composites. The thermal decomposition, ignition and combustion characteristics of MH 2 -based energetic composites were studied. The results showed that molecular perovskite energetic material DAP-4 was beneficial as oxidant in MH 2 -based high-energy solid composites, which were originated from its high energy properties and strong oxidation capacity. The ignition and combustion reaction mechanisms of MH 2 with DAP-4 as oxidant were provided. This work offered an effective way to realize energy-releasing performance of MH 2 by molecular perovskite energetic materials introduced for their potential application.
研究领域:
材料科学
·
能源化学
✓ 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）