International Journal of Applied Ceramic Technology
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2024
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IF 1.8
Dian Zhang,Xuan Liu,Yijun Liu
Conventional aluminum nitride (AlN) ceramics exhibited insufficient mechanical properties expected from their potential applications in the presence of dynamic loads and intensive stresses caused by thermal shock. In this study, the mechanical properties of AlN ceramics were enhanced by toughening them using AlN whiskers (AlN w ) via gel casting followed by low-temperature sintering at 1650°C. The addition of AlN w simultaneously increased the bending strength, toughness and thermal conductivity of the AlN ceramics. The maximum values of the bending strength, toughness, and thermal conductivity of 9.0 wt% AlN w /AlN were 303.92 MPa, 3.92 MPa·m 1/2 and 186.53 W·m −1 ·K −1 , respectively, which were higher than those of the AlN ceramics by 39.93%, 61.31% and, 15.61%, respectively. The AlN w in AlN w /AlN ceramics tightly bonded with the ceramic matrix, leading to two characteristic toughening mechanisms in the ceramics: crack pinning and deflection at irregular grain boundaries caused by doped whiskers, as well as bridging and stress relaxation caused by whiskers incorporated with the grains. Moreover, the one-dimensional morphology of AlN w can provide a channel for quick photon transport, thereby enhancing the thermal conductivity of AlN w /AlN.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Crystals
·
2023
·Vol. 13
·期 1
·107
·
IF 2.7
Shaocong He,Yehua Li,Xiao Zong,Shanghua Wu
In this work, Al2O3-AlN composite ceramics with high bending strength and thermal conductivity were fabricated by Digital Light Processing (DLP). The influence of AlN content on the rheological and cure behavior of Al2O3-AlN suspensions, as well as the microstructure, thermal conductivity, and bending strength of Al2O3-AlN ceramics, were systematically investigated. The result shows that the viscosity and cure ability of the suspensions were decreased with the increase of AlN content, which are beneficial to the spreading and printing accuracy of the suspensions. Besides, the bending strength of ceramics can be improved due to the residual stress by the introduction of AlN. Approaches were employed to minimize the formation of AlON in Al2O3-AlN ceramics by optimizing the amount of AlN and the sintering temperature. The thermal conductivity and bending strength of Al2O3-AlN ceramics were 31.72 ± 0.45 W/(m·K) and 572.73 ± 59.40 MPa, respectively, which are much higher than those of Al2O3ceramics fabricated under the same condition. Finally, complex-shaped Al2O3-AlN ceramics components have been successfully fabricated by DLP, which may provide an opportunity to broaden the application of Al2O3-AlN composite ceramics in heat dissipation components.Keywords:Al2O3-AlN composite ceramics;Digital Light Processing;mechanical properties;thermal conductivity
研究领域:
材料科学
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制造工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2022
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IF 6.364
Liang Wang,Wei-Ming Guo,Peng-Fei Sheng,Li-Fu Lin,Xiao Zong,Shang-Hua Wu
A new type of non-oxide sintering additive of YH 2 was introduced for the fabrication of AlN ceramics with high thermal conductivity and flexural strength . The effects of YH 2 addition (0–5 wt%) on the phase composition, densification, microstructure, thermal conductivity and flexural strength of pressureless sintered AlN ceramics were investigated and compared with those Y 2 O 3 -added samples (1–5 wt%). The addition of 1 wt% YH 2 led to an in-situ reduction reaction with oxygen impurities, the formation of Y 2 O 3 and finally the formation of yttrium aluminate, which in turn improved densification and microstructure. A high flexural strength (408.69 ± 28.23 MPa) was achieved. The addition of 3 wt% YH 2 increased the average grain size and purified the lattice. All these effects are believed to help achieve a high thermal conductivity of 184.82 ± 1.75 W·m −1 ·K −1 . Although the thermal conductivity was close to the value of 3 wt% Y 2 O 3 -added sample, its strength was much increased to 381.53 ± 43.41 MPa. Meanwhile, it demonstrated a good combination of the thermal conductivity and flexural strength than the values reported in some literature. However, further increasing the YH 2 addition to 5 wt% resulted in a high N/O ratio that inhibited the densification behavior of AlN ceramics. The current study showed that AlN ceramics with excellent thermal and mechanical properties could be obtained by the introduction of a suitable YH 2 additive.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
DOI
高影响因子
KEY ENGINEERING MATERIALS
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2016
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IF 0
Chao Quan,You Fu Zhou,D.C. Huang,Wen Tao Xu
SrAl2O4:Eu2+,Dy3+ long-lasting phosphors were incorporated AlN successfully by a conventional solid-state reaction in the reductive atmosphere. When a certain amount of AlN was doped, the specimen SrAl2O4-3xN2x: Eu2+, 0.01Dy3+ (x = 0.0-0.2) maintained the phase purity. Under the excitation at 398nm, an intense broadband emission centered at 514 nm, originating from the 4f65d1→4f7 transition of Eu2+, was observed. It is noteworthy that partial nitridation leads to an enhancement in the emission intensity up to 240%. The study of thermal stability shows that the intensity of SrAl2O3.55N0.3:Eu2+,0.01Dy3+ phosphor still remains 72% at 150 °C comparing with the initial, while only 62% for the un-doped phosphor. Taking enhanced photoluminescence (PL) property and good thermal stability into account, SrAl2O4-3xN2x:Eu2+, 0.01Dy3+ is a promising candidate for the phosphors used in alternating current (AC) LEDs.
研究领域:
材料科学
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光学
✓ 已验证
DOI
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
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2014
·Vol. 16
·期 26
·13078-13085
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IF 4.198
Dan Xu,Lidong Wang,Weili Li,Wei Wang,Yafei Hou,Wenping Cao,Yu Feng,Weidong Fei
BaTiO3–xAlN (BT–xAlN) composite ceramics were prepared by conventional solid state reaction sintering. The effects of the AlN content on the crystalline structures, densities, and electrical and mechanical properties of the BT ceramics were investigated. The BT–1.5%AlN ceramic exhibits a good piezoelectric constant of 305 pC N−1 and an improved Vickers hardness of 5.9 GPa. The enhanced piezoelectricity originates from interactions between defect dipoles and spontaneous polarization inside the domains due to the occurrence of local symmetry, caused by the preferential distribution of the Al3+–N3− pairs vertical to the c axis. The hardening of the material is attributed to the improved density, and particle and grain boundary strengthening. Our work indicates that if a suitable doping ion pair is designed, lead-free ceramic systems prepared from ordinary raw materials by a conventional sintering method have a high probability of exhibiting good piezoelectric and mechanical properties simultaneously.
研究领域:
材料科学
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物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Shitong Yu,Leilei Bie,Zhicheng Luo
Lignin is mainly composed of three basic C9 phenolic monomers, which makes it a formidable challenge to selectively produce C8 phenolic monomers, precursors for the ethylbenzene and styrene, due to intricate C–O and C–C cleavages. Here, we introduce a Ni 0.5% /AlN catalyst, featuring atomically dispersed Ni on a basic AlN support. The catalyst yields 52.7 % relative phenolic monomers with an unparalleled selectivity of 58.7 % for C8 phenolic species (Phenol, 4-ethyl, and Phenol, 4-ethyl-2-methoxy). The inherent basic sites within the AlN support crucially facilitate the formation of quinone intermediates, subsequently directed by single-atom Ni into C8 phenolic monomers. The catalyst showcases robust recyclability over five cycles, because of the strong interactions between Ni and AlN support. This study reveals a synergistic interplay between single-atom Ni and the basic support, paving a transformative pathway for the selective valorization of lignin.
研究领域:
化学工程
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催化
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可再生能源
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绿色化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Xidong Wang,Yanrong Liang,Jiawei Liu,Qianxiong Wen,Cong Zhao,Xiaojuan Liang,Zhaopin Chen,Weidong Xiang
Phosphors in glass films (PiFs) is considered ideal conversion materials for laser lighting, but heat dissipation issue is the main challenge limiting its development. Therefore, it is urgent to find more excellent heat dissipation materials. Herein, we proposed to use AlN with high thermal conductivity as the substrate, and innovatively introduced TiO 2 coating to improve the interface reflection ability and solve the possible problems of shedding and cracking. After a series of optimizations, the LSN PiG-TiO 2 -AlN (PTA) color converter obtained a high thermal conductivity of 29W m −1 k −1 and a low surface temperature. At an input power of 5.2W, the luminous efficiency can reach 175 lm/W and the relative initial intensity can still be maintained by 95.3% at 200 °C. Benefiting from the extremely strong heat dissipation capacity of the AlN substrate, the LSN PTA color converter maintains its relative luminous intensity at 95 % of the initial intensity after 24 h of continuous illumination, which is the best value recorded so far. In addition, LSN PTA is combined with CaAlSiN 3 :Eu 2+ phosphor to achieve high-quality white light with a CRI of 82.5. The above results indicate that LSN PiG-TiO 2 -AlN color converters have a promising research prospect in the field of laser lighting.
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2025
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IF 14.3
Yanrong Liang,Xiangjia Sun,Tongtong Zhu,Haitao Wang,Shuo Wang,Xiaojuan Liang,Weidong Xiang,Weiwei Huan,Jie Li,Junlong Wang
In recent years, the development of solid-state lighting devices has increasingly shifted towards high-power laser illumination, making it imperative to develop fluorescent conversion materials with exceptional thermal stability and luminous quality. In this study, we introduced a highly reflective TiO 2 substrate in combination with a high thermal conductivity AlN substrate to design a Ce:YAG-PiG-TiO 2 -AlN Film (Ce:YAG PTAF) color converter with outstanding photothermal performance. Remarkably, the thermal conductivity of this material reaches 48.28 W m −1 K −1 . Notably, the optimized PTAF can withstand a high-power output of up to 12.14 W in a static environment, with a maximum luminous flux (LF max ) of 2284.6 lm and maximum luminous efficacy (LE max ) of 222.35 lm W −1 , showcasing its excellent optical properties. Furthermore, the fabricated Ce:YAG-PiG-TiO 2 -AlN-Wheel (Ce:YAG PTAW), equipped with a motor operating at 7200 r/min, emits an extraordinary brightness of 4404 lm under 88 W of ultra-high laser irradiation, with stability surpassing that of commercial silicone color wheels, thanks to its superior Li 2 O-Al 2 O 3 -SiO 2 (LAS) glass system. Interestingly, we designed an innovative spatially separated two-color segmented wheel structure, effectively mitigating the photon reabsorption phenomenon caused by the overlap of the fluorescent powder absorption peaks. When the ratio of Ce:YAG to Ce:GdYAG is 240:120, it yields white light with a color rendering index (CRI) of 80.2, and luminous flux remaining at 3317.8 lm. When encapsulated in a reflective module, it accurately reflects the true color states of objects. These results collectively indicate that both Ce:YAG PTAF and PTAW possess significant application potential in the realm of high-power laser illumination.
研究领域:
光学材料
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固态照明
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热管理技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
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2024
·
IF 3.2
Bo Wang,Zihao Pan,Ziyan Zhao,Bo Zhou,Xuejian Liu,Zhengren Huang,Yan Liu
In this paper, we designed two series of the ZnO-B 2 O 3 -SiO 2 (ZBS) glass to explore their applicability for joining AlN ceramic. The density, flexural strength, structure, characteristic temperature, coefficient of thermal expansion (CTE) and crystallization behavior of the ZBS glass with varying ZnO and B 2 O 3 content were systematically studied. The results show that as B 2 O 3 content increase, the glass network is disrupted with the transition from three-dimensional shelf-like structure [BO 4 ] to two-dimensional layers [BO 3 ], increasing the number of the broken bonds, while an increase in ZnO results in a more compact glass network structure. We also found that both glass transition temperature (T g ) and softening temperature (T S ) exhibit a declining trend with the increase in B 2 O 3 and ZnO. Zn 2 SiO 4 and ZnAl 2 O 4 , began to precipitate after heat treatments in all the samples except 60ZnO-30B 2 O 3 –10SiO 2 (abbreviated as B30), where the diffraction peaks do not appear in Zn 2 SiO 4 but in Zn 4 B 6 O 13 . Notably, Zn 2 SiO 4 is the main phase for most samples while the main phase of B30 sample is ZnAl 2 O 4 . The CTE increases from 4.6 to 5.03 (× 10 –6 / °C) and 4.23 to 4.73 (× 10 –6 / °C) with an increase of B 2 O 3 and ZnO content, respectively. Among these, the CTE of B30 sample is compatible with that of AlN ceramic substrate. The optimal shear strength, 60.32±10.26 MPa, was achieved with B30 samples at 750 °C. The high strength was attributed to the interfacial reaction that leads to strong chemical bonding and the uniform distribution of the ZnAl 2 O 4 in the interlayer, which reinforces the strength of the interlayer itself.
研究领域:
材料科学
·
无机非金属材料
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Guangchao Xing,Chengji Deng,Jun Ding,Hongxi Zhu,Chao Yu
AlN-SiC porous composite ceramics were fabricated by heat-treating Al 4 SiC 4 porous ceramic green body prepared using the foaming method under flowing nitrogen. The porous structure could provide increased nitrogen diffusion channels, leading to a decrease in N 2 diffusion resistance and an increasing degree of nitridation. The micro-morphology of AlN was in the form of particles or whiskers and influenced by heating temperature and time parameters. AlN has good dispersibility with SiC particles, resulting in local homogeneous chemical composition of prepared AlN-SiC composite ceramics. Furthermore, the potential reaction mechanism responsible for the synthesis of AlN-SiC porous composite ceramics during the nitridation was revealed. This simple approach may be used for large-scale synthesis of AlN-SiC porous composite ceramics.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2016
·
IF 3.014
Shifeng Huang,Feng Gao,Qinggang Li,Xin Cheng
Samples with various ratios of AlN/Al 2 O 3 were fabricated via vacuum hot-pressing at 1700 °C under an applied pressure of 30 MPa for 90 min using Y 2 O 3 as a sintering aid. The densification process, microstructural development, and formation of AlON phase from Al 2 O 3 and AlN were investigated. Al 2 O 3 additive can improve the physical and mechanical properties , and purification of the grain boundaries. AlON are almost formed completely when the content of Al 2 O 3 is 80 vol%. The effects of composition, microstructure, and exposure time at 1400 °C on the oxidation behavior of AlN samples with different amounts of Al 2 O 3 were investigated. The sample with 80 vol% alumina has the best oxidation resistance .
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 Advanced Ceramics
·
2021
·Vol. 10
·期 6
·1317-1325
·
IF 6.707
Liu Zetan,Zhao Shiqiang,Yang Tian,Zhou Ji
It is possible to improve the machinability of aluminum nitride-hexagonal boron nitride (AlN-h-BN) ceramics while maintaining high strength and high thermal conductivity. The composite ceramics with 0–30 wt% BN as secondary phase were prepared by hot pressed sintering, using yttrium oxide (Y 2 O 3 ) as sintering aid. The phase composition, density, microstructure, mechanical properties, thermal conductivity, and dielectric properties were investigated. The sintering additives were favorable to purify the grain boundaries and improve densification, reacting with oxide impurities on the surface of raw material powder particles. The optimum BN content improved the flexural strength and fracture toughness of composite ceramics with 475 MPa and 4.86 MPa·m 1/2 , respectively. With increasing the amount of BN, the thermal conductivity and hardness of composites gradually decreased, but the minimum value of thermal conductivity was still 85.6 W·m −1 ·K −1 . The relative dielectric constant and dielectric loss tangent of the samples ranged from 6.8 to 8.3 and from 2.4 × 10 −3 to 6.4 × 10 −3 , respectively, in 22–26 GHz.
研究领域:
材料科学
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工程学
✓ 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）