CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Weide Wang,Dongxu Yao,Hanqin Liang,Yongfeng Xia,Kaihui Zuo,Jinwei Yin,Yu-Ping Zeng
The effect of the GdH 2 on the shrinkage behavior, microstructure, thermal conductivity , and flexural strength was investigated. The pre-sintering enables the elimination of native SiO 2 and the simultaneous formation of Gd 2 O 3 . The N/O ratio in the liquid phase was increased because of the increasing Gd 2 O 3 /SiO 2 ratio, resulting in the restricted shrinkage during gas pressure sintering. The high N/O ratio in the liquid phase benefits not only the nucleation and growth of β-Si 3 N 4 but also the removal of lattice oxygen, leading to the increase of thermal conductivity . Although the replacement of Gd 2 O 3 by GdH 2 leads to enhanced flexural strength at low temperature, it tends to reduce the flexural strength at high temperature. This variation related largely to the exaggerated bimodal microstructure. This work signifies that GdH 2 is an effective sintering additive for obtaining Si 3 N 4 ceramics with both high flexural strength and high thermal conductivity.
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高影响因子
ACTA MATERIALIA
·
2024
·
IF 8.3
Xingqi Liao,Mingqing Liao,Chong Wei,Zhiheng Huang,Wenjiu Duan,Xiaoming Duan,Delong Cai,Laurent Gremillard,Zhihua Yang,Dechang Jia,Yu Zhou
For the engineering applications of freeze-cast porous ceramics, the demand targets are often multiple and competing, which is a challenging problem to seek a Nash equilibrium in the high-dimensional design space. An accurate and robust quantification of process-structure-property correlations would provide an effective path to find the set of Pareto optimal materials for one specific need. In this work, using porous Si 3 N 4 -Si 2 N 2 O ceramics as the model materials, a hybrid model for the quantitative design of the microstructure and mechanical properties is developed from four physics-based process-microstructure models with sintering, solidification, phase transformation and grain growth kinetic theories, and the subsequent data-driven structure-property model utilizing a machine learning method, artificial neural network (ANN). The SHapely Additive exPlanations (SHAP) analysis is further introduced to interpret the ANN model and mathematically identify the contribution of each microstructure feature descriptor toward target mechanical property outputs. These results present a systematic understanding of the process-structure-property relationships through the hybrid model, guiding the optimal design of the freeze-cast porous ceramics with required microstructures and mechanical properties.
研究领域:
材料科学
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机器学习
·
工程学
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Xinyi Gui,Mingfen Zhang,Puhao Xu,Guiwu Liu,Qinhan Guo,Xiangzhao Zhang,Haining Meng,Guanjun Qiao
Reactive air brazing of Si 3 N 4 ceramic was successfully achieved by using Ag-CuO filler metal. The effects of CuO content on the wettability of Ag-CuO/Si 3 N 4 system and the shear strength of Si 3 N 4 /Si 3 N 4 joint were investigated, and meanwhile the interfacial behavior was analyzed and discussed. Moreover, the work of adhesion, interfacial energy, and electronic properties of Ag/Si 3 N 4 , Ag/CuO and Ag/SiO 2 interfaces were evaluated by first-principles calculations. The Ag-CuO/Si 3 N 4 system transforms from no-wetting into wetting due to the oxidation of Si 3 N 4 substrate and the formation of SiO 2 layer on the substrate surface. The maximum average joint shear strength of over 50 MPa is obtained as the CuO content is 8 at.%. Compared with the Ag(111)/Si 3 N 4 (0001) interface, the Ag(110)/CuO(001) and Ag(110)/SiO 2 (001) interfaces show stronger interfacial bonding due to the formation of Ag-O ionic bond, indicating that the addition of CuO and the formation of SiO 2 contribute to the enhancement of interfacial bonding.
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高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2026
·
IF 19.9
Dongfang Xu,Lei Feng,Qiang Song,Qiangang Fu
Reconciling ultralight compliance with ultrahigh-temperature oxidation resistance under one-sided heating remains a key challenge for ceramic aerogels in extreme thermal protection systems (TPS). Here we report a spatially programmed rigid–flexible aerogel, locally impregnated ZrO 2 /SiO 2 /C–Si 3 N 4 nanoribbon aerogel (L-ZSC-SNRA), fabricated by bidirectional freeze-casting and stepwise localized impregnation of polycarbosilane (PCS) and Zr-containing PCS precursors followed by pyrolysis. The ≈30 mg cm −3 monolith is functionally graded, decoupling hot-face protection from cold-face compliance by integrating a multiphase ZrO 2 /SiO 2 /C hot-face armor with a porous elastic Si 3 N 4 skeleton. Consequently, L-ZSC-SNRA achieves 98% recoverability at 60% strain with stable 1000-cycle compression and retains ≈83% recoverability after single-sided static oxidation in air at 1600°C. It exhibits low thermal conductivity from 25°C–1000°C (38.6–105.2 mW m −1 K −1 ) and strong flame shielding under a ≈1500°C torch, limiting the cold-side temperature to 218.1°C for a 10-mm slab after 10 min. Notably, the thermal-conductivity increase at 1000°C after the 1600°C static oxidation is only 6.8%, evidencing robust high-temperature thermal-transport stability. This work overcomes the key trade-off between ultralight compliance and ultrahigh-temperature oxidation durability, demonstrating a scalable locally graded coating–architecture strategy for oxidizing extremes relevant to TPS.
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高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2025
·
IF 7
Wei Feng,Jian Zhang,Ruxia Liu,Yong Xiao,Guoqiang Luo,Qiang Shen
Particle-reinforced composite fillers allow precise control of joint microstructure to enhance mechanical performance. However, traditional designs often reduce joint deformability and face issues like particle agglomeration and poor interfacial wettability. To overcome these limitations, a micro-network of Cu-Ti reinforcements within the brazing seam via Ag- x TiH 2 composite filler was developed in this work, which enabled the fabrication of high-strength Si 3 N 4 /Cu joints. Optimal results were achieved with the Ag-4TiH 2 filler, wherein a eutectic liquid formed at the Ag-4TiH 2 /Cu interface during the initial brazing stage. Simultaneously, undissolved Ti reacts with Cu to yield submicron Cu 4 Ti 3 -dominated reinforcements. On the Si 3 N 4 surface, hypostoichiometric TiN/TiN 0 . 61 /TiN 0 . 5 nanocrystals grow sequentially, which is beneficial for enhancing interfacial wettability and bonding reliability. A maximum average shear strength of 186.9 MPa was obtained, a 57.6 % improvement over the conventional AgCuTi filler. The fracture mechanism underwent a notable transformation: brittle failure at mixed regions of Si 3 N 4 and the reaction layer in AgCuTi joints was replaced by ductile failure at the interface between the Cu matrix and the brazing seam in Ag-4TiH 2 joints. The Cu 4 Ti 3 -dominated micro-network offers distinct advantages by enabling controllable in-situ growth that prevents agglomeration while maintaining joint deformability through the synergy effect of the abundant retention of ductile Ag(s, s) and decent elastic modulus and yield strength increment, and regulates the interface reaction to yield a thinner Ti-N layer instead of a TiN/Ti 5 Si 3 dual-layer. These features collectively contribute to the notable mitigation of residual stress within Si 3 N 4 /Cu joints.
研究领域:
材料科学
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焊接技术
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陶瓷金属连接
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复合材料
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界面工程
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高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Chi Zhang,Ning Wang,Hai Chang,Yingna Wu,Rui Yang,Dongxu Yao,Zirong Zhai
This study addresses challenges in manufacturing high-quality silicon nitride (Si 3 N 4 ) products using vat photopolymerization (VPP), a method that enables highly precise and complex manufacturing that was previously unachievable. A comparison of VPP and cold isostatic pressing (CIP) showed that the intergranular phases of VPP samples exhibited continuous network assembly, while the intergranular phases of CIP samples were dispersed and aggregated. For densification, VPP samples required more aggressive sintering conditions and a higher MgO content. This prolonged densification process adversely affected thermal conductivity, only reaching a maximum of 70.91 W m −1 ·K −1 . Through annealing, thermal conductivity of VPP sample improved by 72.44 %, narrowing the gap with CIP sample (90.28 W m −1 ·K −1 ) and reaching up to 96.20 W m −1 ·K −1 . Si 3 N 4 sample exhibiting high flexural strength of 908.28 ± 46.90 MPa were prepared using VPP. This study proposes a viable approach for producing high-performance Si 3 N 4 heat exchangers and other complex devices via VPP.
研究领域:
材料科学
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制造工程
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2017
·
IF 3.454
Y.L. Zhuang,T.S. Lin,S.J. Wang,P. He,D.P. Sekulic,D.C. Jia
The Ti 22 Si 78 (wt.%) braze was used to bond porous BN/Si 3 N 4 ceramic. The results revealed that the joint strength was low. In order to improve the joint strength, a carbon coated modification of the porous BN/Si 3 N 4 substrate, achieved by the pyrolysis of phenol-formaldehyde resin was suggested. The thickness of carbon layer was controlled by the volume ratio of phenol-formaldehyde resin and methyl alcohol (R/M). The effect of the carbon layer on the microstructure and mechanical properties of the joint was examined. It was established that the maximum joint strength was achieved at the level of 80 MPa (as opposed to the uncoated joint with only 30 MPa) when R/M was 1:2, at the given brazing temperature. The improvement of the joint strength is attributed mainly to the formation of a SiC infiltration reaction layer, a significant population of SiC nanowires, as well as TiN 0.7 C 0.3 and TiB 2 particles.
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2025
·Vol. 46
·期 7
·118118
·
IF 6.2
Yifei Yan,Chuanzhen Huang,Zhenyu Shi,Zhen Wang,Longhua Xu,Shuiquan Huang,Meina Qu,Zhengkai Xu,Dijia Zhang,Baosu Guo,Tianye Jin,Xiaodan Wang,Hanlian Liu,Dun Liu,Peng Yao
The fabrication of porous Si 3 N 4 /BN ceramics for high-temperature radomes via vat photopolymerization is hindered by excessive slurry viscosity, which restricts the recoating process, and by limited curing depth. To overcome these challenges, we developed a high-performance slurry using a synergistic strategy combining BN surface functionalization with optical modulation via SiO 2 . Ultrasonic-assisted hydrolysis and silane coupling significantly enhanced interfacial compatibility with the resin, reducing viscosity from 20.83 to 4.51 Pa·s at a shear rate of 30 s −1 . Simultaneously, the incorporation of refractive-index-matched SiO 2 effectively suppressed light scattering, thereby increasing curing depth and structural integrity. Furthermore, SiO 2 regulated liquid-phase behavior during sintering to optimize the microstructure. The resulting ceramics exhibited an exceptional property balance: 42.14 % porosity, 68.2 MPa flexural strength, a dielectric constant of 2.56, and a loss tangent of 6.85 × 10 −3 . These metrics satisfy the stringent requirements for wave-transparent applications, offering a robust pathway for manufacturing complex-shaped components.
研究领域:
材料科学
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无机非金属材料
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陶瓷工程
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复合材料
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光电功能材料
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高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Xuan Liu,Dian Zhang,Rongrong Ma,Yu Wang,Xiaofeng Yang,Yijun Liu
With the rapid development of hypersonic vehicles and broadband wave-transparent radome, Si 3 N 4 porous ceramics (Si 3 N 4 -PC) have attracted attention due to their excellent intrinsic properties of Si 3 N 4 and high porosity. However, its high porosity results in low strength and toughness, which are fundamental properties for radome. Reaction bonded (RB) Si 3 N 4 -PC has advantages of dielectric properties and cost over general phase transformation sintering (PTS) and sintered reaction bonded (SRB) Si 3 N 4 -PC while it has been neglected in recent years. In this study, RB and SRB Si 3 N 4 -PC prepared by non-aqueous gelcasting and the influence of Si powders ingredient on their properties are discussed in order to illuminate the potential of RB Si 3 N 4 -PC in wave-transparent materials. The results show that RB Si 3 N 4 -PC with dual-granularity ingredients of 5 μm & 45 μm produces a two-tier tissue of framework of coarse whiskers enhanced by a network of tiny whiskers. SRB Si 3 N 4 -PC evolves into a two-tier tissue of framework of columnar and rod-like grains joining together to brace each other. The two-tier microscopic tissue strongly reinforces and toughens the structure and results in higher σ F and γ wof . As a result, the RB and SRB Si 3 N 4 -PC of dual-granularity of 5 μm & 45 μm obtain the maximum σ F of 109.94 MPa and 119.56 MPa as well as maximum γ wof of 990.74 J m -2 and 1167.88 J m -2 , respectively. Furthermore, the ε′ and tanδ of RB and SRB Si 3 N 4 -PC of dual-granularity of 5 μm & 45 μm are about 4.20 and 4.52 as well as 7.01 × 10 -3 and 22.90 × 10 -3 , respectively. It is concluded that RB Si 3 N 4 -PC of dual-granularity has good mechanical and dielectric properties, which are favorable for radome.
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高影响因子
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