CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Minhao Shen,Renli Fu,Yi Zhang,Kuang Sun,Wei Xu,Yanlin Jiang,Zhe Zhao,Ming Liu
Vat photopolymerized 3D printing technology can be used to fabricate ceramics with complex shapes. However, the extensive use of photosensitive resins as binders is not conducive to achieving crack-free ceramic green parts, especially the Si 3 N 4 ceramics with the weak interlayer bonding. In this work, the influence of different debinding atmosphere on the pyrolysis process of organics in vat photopolymerization 3D printed Si 3 N 4 green parts was investigated. The results showed that the use of 95 vol% N 2 +5 vol% H 2 atmosphere can effectively inhibit the cracking during the debinding process, especially the wall thickness of the 3D printed defect-free Si 3 N 4 green body was successfully increased to 5 mm, and the obtained sintered Si 3 N 4 ceramics exhibited higher true densities and better mechanical properties. The debinding atmospheres proposed in the current work provided additional options of debinding atmosphere for achieving high-performance 3D printed Si 3 N 4 ceramics and are expected to be expanded to other photosensitive slurry systems, with the potential to enable the production of ceramic components with the larger wall thicknesses.
研究领域:
材料科学
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陶瓷制造
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3D打印技术
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产品关联
DOI
高影响因子
Silicon
·
2021
·Vol. 14
·期 11
·6341-6350
·
IF 2.67
Xu Hongli,Jin Xing,Zhou Xuetong,Du Xinghong,Xing Pengfei,Zhuang Yanxin
In this paper, the acceleration effect of nickel (Ni) on the direct nitridation process of the diamond-wire saw powder (DWSP) was investigated. The DWSP doped with Ni additives were nitrided at different temperatures. To study the mechanism of accelerated nitridation, the thermodynamics of Si-O-N-Ni and nitridation processes were analyzed by FactSage 7.2 and single-crystal silicon blocks were also nitrided instead of the DWSP. The results revealed that Ni decreased the nitridation temperature at which the DWSP began to gain significant weight and exhibited an excellent accelerating effect on the nitridation of the DWSP. At 1300°C the DWSP containing 2.0 wt% Ni additives had been completely nitrided within 2 h, whereas the DWSP without Ni additives had not been nitrided yet. Based on the equivalent substitution experiment, it could be concluded that the presence of Ni additives accelerated the nitridation and promoted the formation of the α-Si 3 N 4 nanorods through facilitating the generation of the SiO(g) and destructing the silica film on the surface of silicon at lower temperature. Meanwhile, Ni additives also played an important part in the growth of α-Si 3 N 4 nanorods by forming liquid Ni-Si alloy in the product.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Rufei Chen,Wenyan Duan,Gong Wang,Bingshan Liu,Yantong Zhao,Shan Li
Wave-transmitting materials are a kind of multi-functional materials that protect the normal operation of communication and guidance systems of spacecraft in harsh environments. In this paper, we fabricate a broadband microwave transparent Si 3 N 4 -SiO 2 composite ceramic with excellent performance through digital light processing (DLP) 3D printing technology. The influences of sintering temperature on the weight increase rate, density, dimensional shrinkage, phase composition, microstructure, bending strength and dielectric properties of Si 3 N 4 -SiO 2 ceramic were all systematically studied. The strength of Si 3 N 4 -SiO 2 ceramic sintered at 1350 ℃ was 77 ± 5 MPa. The relative permittivity of the ceramic is within the range of less than 4, and the loss tangent can be below 0.003. The 3D printed Si 3 N 4 -SiO 2 ceramic material exhibited excellent wave-transparent performance.
研究领域:
材料科学
·
电子工程
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Zhangyi Huang,Li Ying Liu,Jianming Yuan,Huilu Guo,Haomin Wang,Pengcheng Ye,Zehui Du,Yida Zhao,Hao Zhang,Chee Lip Gan
Si 3 N 4 cellular ceramics with large thickness/length ratio (up to ∼12.0) have been successfully prepared by stereolithography 3D printing with highly viscous (viscosity >10.0 Pa‧s at 30 s −1 shear rate), self-holding pastes. Due to the high viscosity and low curing depth of the paste, structural defects are commonly found in the printed honeycombs or lattices and anisotropic surface roughness is present. The structural defects can be reduced by aligning the lattice orientation at 45° relative to the paste recoating direction to reduce shear stress concentration at the cured part beneath. The resultant honeycombs and simple cubic lattices with density of ∼1.5–1.6 g/cm 3 exhibit compressive strength as high as 1.1 GPa and 290.7 MPa, respectively. The specific compressive strength of honeycombs increases from 298.6 to 681.7 MPa‧cm 3 /g with the ceramic volume fractions increase from 0.19 to 0.52, surpassing that of many other ceramic honeycombs and lattices with similar density reported so far. The controlling factors governing the defect formation, surface finish and mechanical properties of the printed cellular ceramics are discussed thoroughly.
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
MATERIALS CHARACTERIZATION
·
2024
·
IF 4.8
Yunwei Shi,Yichao Ren,Qianglong He,Jinghan Wang,Aiyang Wang,Hao Wang,Weimin Wang,Zhengyi Fu
Functionally graded materials (FGMs) have attracted more and more attention due to their graded changes on composition or microstructure to satisfy some conflicting properties in one component. However, the interfacial stress induced by the composition difference across an interface would degrade the reliability of components and hinder its advancement. Herein, a general process to fabricate continuously and symmetrically graded Si 3 N 4 -based ceramics is designed to address the problem above. By the combination of gaseous gradient diffusion and in-situ gas reaction, the graded ceramics with hard surface and tough core are first prepared under uniformly thermal field. The edge area of graded ceramics exhibits fine microstructure, high hardness (19.82GPa), and low fracture toughness (4.73 MPa·m 1/2 ), while the interior exhibits a distinct difference with coarse grains, low hardness (18.31GPa) and high fracture toughness (6.12 MPa·m 1/2 ). The thickness of continuously graded microstructure is effectively controlled and regulated by optimizing sintering regimes.
研究领域:
材料科学
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陶瓷工程
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制造工艺
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Tao Chen,Shujin Li,Ke Chen,Mazhar Hussain Danish,Hui Liu,Di Li,Hongxing Xin,Yongsheng Zhang,Jian Zhang,Xiaoying Qin
Bi2Te3-based thermoelectric (TE) materials are the state-of-the-art compounds for commercial applications near room temperature. Nevertheless, the application of the n-type Bi2Te2.7Se0.3 (BTS) is restricted by the comparatively low figure of merit (ZT) and intrinsic embrittlement. Here, we show that through dispersion of amorphous Si3N4 (a-Si3N4) nanoparticles both 14% increase in power factor (at 300 K) and 48% decrease in lattice thermal conductivity are simultaneously realized. The increased power factor comes from enhanced thermopower and reduced electrical resistivity while the reduced lattice thermal conductivity originates mainly from scattering of middle- and low-frequency phonons at the incorporated a-Si3N4 nanoparticles. As a result, a large ZTmax = 1.19 (at 373 K) and an average ZTave ∼ 1.12 (300–473 K) with better mechanical properties are achieved for the BTS/0.25 wt % Si3N4 sample. Present results demonstrate that the incorporation of a-Si3N4 is a promising way to improve TE performance.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Shile Chen,Liang Wang,Gang He,Gang Shao,Hailong Wang,Jiangtao Li,Chang-An Wang
Nitride based ceramics are considered as a kind of promising material for structural and functional integration due to their robust structure, extreme environmental resistance and electromagnetically transparency. It is still challenging to prepare nitride based ceramics with homogeneous and controllable microstructure because of their low self-diffusion coefficient and difficulty in sintering. Here, we developed a gelcasting-SHS process by combining gelcasting forming and self-propagating high temperature synthesis (SHS) for the preparation of porous BN-Si 3 N 4 composite ceramics. First, carbon residue problem in the gelcasting -SHS process was studied. Based on the result, porous BN-Si 3 N 4 composite ceramics with high porosity (69.42 ~ 86.48%), high strength (21.7 ~ 81.0 MPa) and low dielectric constants (1.42 ~ 2.87) were synthesized. In addition, the thermal shock resistance of porous BN-Si 3 N 4 composite ceramics until 1000 ℃ was evaluated.
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
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yang Wang,Wenjie Yuan,Weijian Han,Jianwei Gao,Hao Li,Tong Zhao
A simple and scalable approach to fabricate monodispersed Si 3 N 4 hollow microspheres (Si 3 N 4 HMs) with uniform spherical structures is proposed in this study. This approach involves spray drying of Si 3 N 4 precursor, followed by carbothermal reduction nitridation. The homogeneous Si 3 N 4 precursor was first obtained by mixing phenolic resins and silicon resins, which are carbon and silicon sources, respectively. The spray drying process was then tuned by regulating the viscosity of the precursor by adding polyvinyl butyral in an appropriate ratio. Next, the hollow precursor microspheres were pyrolyzed at 1500 °C for 6 h, while ensuring that the shells of the obtained Si 3 N 4 HMs remained intact. Porous Si 3 N 4 ceramics with different contents of Si 3 N 4 HMs were then prepared using the gel-casting method. It was observed that the densities and dielectric constants of the porous Si 3 N 4 ceramics decreased with an increasing Si 3 N 4 HMs content. Thus, the proposed approach can be used for the synthesis of Si 3 N 4 HMs, that can be further processed into ceramic materials with both low densities and dielectric constants.
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
Coatings
·
2023
·Vol. 13
·期 2
·475
·
IF 3.4
Shuai Guo,Fusheng Zhu,Zhimeng Xiu,Mu Zhang,Xudong Sun
In this study, a type of micro-nano Si3N4matrix ceramic cutting tool material was successfully prepared by controlling the addition amount of TiC0.7N0.3and the hot-pressing sintering temperature. The effects of different volume fractions of TiC0.7N0.3on the microstructure, mechanical properties, particle size distribution, and relative density of Si3N4ceramic tools at the same temperature were investigated. The results show that the addition of TiC0.7N0.3makes the β-Si3N4grains with different diameters and aspect ratios interlaced and tightly bonded, thus achieving the strengthening and toughening effects. In addition, the effects of different hot-press sintering temperatures on the properties of Si3N4ceramic tool materials were studied. It was concluded that the density of the material increased with the increase of the hot-pressing temperature. The relative density, flexural strength, and fracture toughness of the samples with 1 vol% TiC0.7N0.3added at 1750 °C and 30 MPa pressure reached 99.22%, 993 MPa, and 9.81 MPa·m1/2, respectively.Keywords:Si3N4;ceramic cutting tool;hot-pressing sintering;TiC0.7N0.3;self-toughening
研究领域:
材料科学
·
机械工程
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Wenhu Hong,Shun Dong,Ping Hu,Xiaoguang Luo,Shanyi Du
Enhanced microwave absorption properties of porous PDC-SiC/Si 3 N 4 ceramics were successfully prepared through in situ growth of Si 3 N 4 nanowires (NWs) by the unidirectional freeze casting of Si 3 N 4 /camphene slurries with various polycarbosilane (PCS) contents at 1400 °C in N 2 . Si 3 N 4 NWs were in situ formed in the pore channels via a vapor-solid (VS) mechanism, the content of Si 3 N 4 NWs increased with increasing of PCS content, which tailored the microstructure and mechanical property of porous PDC-SiC/Si 3 N 4 ceramics. With the increase of PCS content, the minimum reflection coefficient (RC) of porous PDC-SiC/Si 3 N 4 ceramic decreased from −20.2 dB to −56.2 dB, and the effective absorption bandwidth (EAB) increased from 5.3 to 7 GHz, demonstrating that the porous PDC-SiC/Si 3 N 4 ceramics decorated with Si 3 N 4 NWs had a superior microwave-absorbing ability, which could be ascribed to the electronic dipole polarization and interfacial scattering enhanced by the various interfaces among Si 3 N 4 , in-situ formed PDC-SiC nanograins, nanosized carbon and Si 3 N 4 NWs phases. These findings provide significance guidance in the development of new broadband EM 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
CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Hanqin Liang,Kaihui Zuo,Yongfeng Xia,Dongxu Yao,Jinwei Yin,Yuping Zeng
Lu-Al-Si-O-N tapes with different thickness were used to join gas pressure sintered Si 3 N 4 ceramics. The microstructure of the joints and the influences of the joint thickness and joining temperature on the bonding strength of the as-joined Si 3 N 4 ceramics have been investigated. The highest bonding strength about ~ 300 MPa of the joined specimens was achieved by using 450 µm interlayer at 1450 °C. The existence of Si 3 N 4 nanowires was beneficial for the improvement of the bonding strength by interweaving the oxynitride glass matrix in the joint region.
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
International Journal of Applied Ceramic Technology
·
2024
·
IF 1.8
Heng Zhang,Dongxu Yao,Yongfeng Xia,Yu-Ping Zeng
Porous Si 3 N 4 ceramics were prepared using the low-toxicity monomer HEMA (2-hydroxyethyl methacrylate) via a modified gel casting method. The rheological properties of Si 3 N 4 slurries were investigated. Triethanolamine with high activity was used as a catalyst and modifier for gelation reactions, effectively improving the curing rate and suppressing the inherent surface oxygen inhibition in such process systems. With an increase in solid loading of the slurry, the drying shrinkage (12.3% to 5.4%) significantly decreased, while the green body density (44.0%–49.0%) and flexural strength (9.65–16.46 MPa) increased, demonstrating an excellent mechanical strength. After sintering at 1700°C, the porous Si 3 N 4 ceramics prepared with 24–36 vol% solid loading slurry exhibited a flexural strength of 144.39–193.66 MPa and a porosity of 55.8% to 49.0%. The dielectric constant and loss tangent at 30 GHz ranged from 2.88 to 3.38 and 1.17–1.56 × 10 −3 , respectively. These ceramics show promising potential applications in high-performance structural ceramics and high-temperature wave-transparent materials.
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
危险品化学品经营许可证（带存储）