Additive Manufacturing
·
2022
·
IF 11.632
Meng Li,Hai-Lu Huang,Jia-Min Wu,Ya-Ru Wu,Zhang-Ao Shi,Jing-Xian Zhang,Yu-Sheng Shi
It is difficult to form Si 3 N 4 ceramics by DLP technology owing to the high refractive index and high ultraviolet (UV) absorption of Si 3 N 4 powder. In this paper, the Si 3 N 4 ceramics were successfully fabricated by DLP technology using Si 3 N 4 powder coated with Al 2 O 3 -Y 2 O 3 sintering additives. The effects of the coating amount of sintering additives on the properties of Si 3 N 4 ceramic slurry , green bodies and parts after sintering were systematically studied. When Al(NO 3 ) 3 and Y(NO 3 ) 3 solutions were added at a content of 20 mL/100 g Si 3 N 4 , the slurry with lowest viscosity (0.042 Pa·s at a shear rate of 30 s −1 ) and a higher monolayer curing depth (47.9 ± 1.2 µm) was obtained, the relative density and flexural strength of the Si 3 N 4 ceramics reached maximum values at 85.4% ± 0.3% and 149.2 ± 1.9 MPa. The shrinkage of the Si 3 N 4 ceramics remained almost unchanged after coating Al 2 O 3 -Y 2 O 3 sintering additives. Finally, the Si 3 N 4 ceramics with excellent quality and clear outline were well prepared. This research has laid a certain experimental basis for DLP forming Si 3 N 4 and other non-oxide ceramics, which is of great researching significance.
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
CONSTRUCTION AND BUILDING MATERIALS
·
2020
·
IF 4.419
Yang Chen,Chengji Deng,Xing Wang,Jun Ding,Chao Yu,Hongxi Zhu
Si 3 N 4 -MgO-C refractories were prepared using fused magnesia, flake graphite, and Si powder-supported Fe(NO 3 ) 3 ·9H 2 O as the raw materials and phenolic resin as the binder under the flow of N 2 . The effect of different nitriding temperatures on the morphology and production of Si 3 N 4 in the uncatalyzed refractories was investigated. The effect of the morphology of β-Si 3 N 4 on the properties of the refractories with different catalyst contents was investigated. The oxidation resistance of the refractories was also investigated. The results showed that the increase in the nitriding temperature was beneficial for the formation of β-Si 3 N 4 in the refractories. However, very high nitriding temperatures generated a large number of pores in the refractories and deteriorated their properties. The refractory with 1 wt% catalyst exhibited good mechanical properties and oxidation resistance. However, the addition of excessive catalyst inhibited the formation of β-Si 3 N 4 and deteriorated the performance of the refractories.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 53
·期 19
·13573-13583
·
IF 2.993
Huang Zhifeng,Wang Zhihao,Yuan Hailong,Zhang Jianwen,Chen Fei,Shen Qiang,Zhang Lianmeng
In this work, Y-, Ce- and Tb-doped Si 3 N 4 nanowires have been successfully synthesized by directly nitriding-doped nanocrystalline silicon powders obtained by cryomilling. The obtained single-crystalline α-Si 3 N 4 nanowires are nearly 20–50 nm in diameter and up to several micrometers in length. The photoluminescence properties of doped Si 3 N 4 nanowires have also been investigated. The Y-doped Si 3 N 4 nanowires exhibit the main peak at 425 nm, Ce-doped Si 3 N 4 nanowires show a narrow emission peak at 450 nm, and Tb-doped Si 3 N 4 nanowires present a strong and sharp emission peak at 545 nm. Combining with our previous works on Al-, La- and Eu-doped Si 3 N 4 nanowires, the effects of dopants with different valence electron configurations on the photoluminescence properties have been explored. The present study provides a guide to fabricate Si 3 N 4 -based nanomaterials for different photonic applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
SOLID STATE PHENOMENA
·
2018
·
IF 0
Ping Ping Zhang,Jing Man,Hong Sheng Wang,Qi Hong Wei,Ying Gai,Bao Xin Zhu,Ling Li
Si3N4-BaTiO3 composite ceramics, a type of high dielectric materials applied in the multifunction radome, were prepared by gas pressure-sintering method. The influences of BaTiO3 power content on the mechanical performances, dielectric properties and microstructure of Si3N4-BaTiO3 composite ceramics were investigated. The results showed that the sintering density, the elastic modulus and the flexural strength of Si3N4-BaTiO3 composite ceramics all firstly increased and then decreased along with the increase of BaTiO3 power in sample. Meanwhile, Relationship between BaTiO3 power content and dielectric properties of Si3N4-BaTiO3 composite ceramics within the frequency range of 8.2–12.4 GHz (X-band) was studied. The average of dielectric constant e of Si3N4-BaTiO3 composite ceramics increased from 7.33 to 9.98 and the average of dielectric loss tand increased from 2.8 ´ 10-3 to 0.0168 when the content of BaTiO3 power increased from 0 to 25 wt.%. The increase of the dielectric properties of Si3N4–BaTiO3 composite ceramics were attributed to the electronic and molecular polarization at interface between Si3N4 and BaTiO3, compared with the pure matrix Si3N4.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Kai Zhang,Yinjie Sun,Yiling Cheng,Sifan Hou,Jinpeng Fan
Inspired by the Bouligand structure in nature, a kind of Inverse-Bouligand structure was designed. Different from the bionic Bouligand structure of a one-dimensional material unit, the inverse-Bouligand structure is obtained by stacking and twisting the ceramic layer with a parallel groove structure. The grooves arranged in parallel are first etched on the ceramic green body and then sintered after stacking and twisting. After sintering, the groove structure can still be maintained, so the resulting laminated twisted groove structure in the bulk forms an inverse-Bouligand structure, which can promote crack deflection and improve the toughness of the material during the fracture process. After testing different twist angles, the results show that when the twist angle is 15°, the toughness of the material can reach 11.22 ± 1.77 MPa m 1/2 , and high strength can be guaranteed. The synergistic effect of interlayer crack deflection and regional crack twist is the main mechanism for the improvement of material toughness.
研究领域:
材料科学
·
陶瓷工程
·
仿生学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED ENERGY
·
2022
·
IF 11.446
Boshu Jiang,Bachirou Guene Lougou,Hao Zhang,Boxi Geng,Lianxuan Wu,Yong Shuai
The solar-driven thermochemical CO 2 -to-CO conversion is an effective way to achieve the mission of carbon peaking and carbon neutrality. However, synthesizing porous reacting materials with excellent thermal stability, hardness and long-term cyclic stability, oxygen exchange capacity, and higher CO 2 -to-CO conversion are the most important challenges associated with the thermochemical CO 2 -splitting approach and technological upscaling to large-scale applications. This study presented the development of NiFe 2 O 4 oxygen carriers, the synthesis method of SiC and Si 3 N 4 supports, and solar-to-fuel processing of the newly prepared materials through CO 2 -splitting under a highly concentrated solar radiative heat flux. The newly synthesized NiFe 2 O 4 @SiC porous redox material resulted in higher solar energy absorption and CO 2 conversion capability with an instantaneous CO production of 410 μmol/g and direct CO 2 -to-CO conversion rate of 18.1 % at 1073–1273 K reaction temperature. The media composite of NiFe 2 O 4 @SiC exhibited high-temperature thermal changes, good thermochemical reaction stability, and a higher CO production rate through six redox cycles compared to NiFe 2 O 4 @Si 3 N 4 porous reacting material. The high oxidation potential and remarkably solar radiative heat flux absorption and thermochemical CO 2 -splitting capacities of the newly developed materials were demonstrated through experimental analysis. The synergistic effect of the oxygen carriers (NiFe 2 O 4 ) and substrate materials including SiC and Si 3 N 4 skeletons for CO 2 -splitting is highlighted. This study provided comprehensive and novel experimental insights that can be used as guidance for theoretical research and application in CO 2 conversion into high-value-added energy products.
研究领域:
材料科学
·
可再生能源
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2018
·
IF 2.606
Te Qi,Zhihao Zhao,Yongqiang Sun,Hangyuan Zhao,Xiaolei Li,Huiming Ji
Porous Si 3 N 4 ceramics with a unique interlocking microstructure have been fabricated by pressureless liquid-phase sintering with YbF 3 and CaF 2 sintering additives at a relatively low temperature (1550 °C). Phase transition and mass diffusion in the low-temperature sintering process are facilitated by YbF 3 and CaF 2 producing plenty of liquid phase owing to their extremely low melting points. As the content of YbF 3 increases from 8.0 wt% to 9.5 wt% and the CaF 2 decreases from 2.0 wt% to 0.5 wt%, the conversion rate of the phase transition from α-Si 3 N 4 to β-Si 3 N 4 increases from 71.1% to 81.2% and the largest average aspect ratio of the β-Si 3 N 4 grains reaches 10.05. At the same time, the porosity declines from 40.4% to 34.9% and the flexural strength increases from 168.5 MPa to 232.1 MPa.
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 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
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Donglin Lu,Ping Yang,Yao Huang,Niansheng Huang,Shanghua Wu
To enhance the thermal conductivity of Si 3 N 4 , a polydopamine (PDA) coating was creatively introduced into ceramics sintered with different additive contents through a two-step sintering process consisting of a first treatment at 1500 °C for 8 h followed by 12 h at 1900 °C under 1 MPa nitrogen pressure. After the first-step sintering, the PDA-coated sample exhibited a higher elimination effect of the liquid phase and an increase in the N/O ratio, which allowed the additives to directly interact with the Si 3 N 4 grains, resulting in a microstructure with more and larger rod-shaped grains. After the second-step sintering, the densified samples of the PDA-coating attained slightly coarser rod-shaped grains, lower O content, higher N/O ratio and peak intensity (XRD) of the Y 2 Si 3 O 3 N 4 phase, thicker grain boundary film, and secondary phases mainly residing in multigrain junctions. Consequently, the thermal conductivity of all the PDA-coated samples typically showed a 10–12% increment in comparison to the PDA-free samples for each additive content.
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 Materials Research and Technology-JMR&T
·
2023
·
IF 6.4
Pengfei Li,Ruiming Yin,Yunfei Bai,Yanhong Ding,Xiaofeng Zeng,Yongquan Li
To reduce the lattice oxygen content of Si 3 N 4 green bodies, samples were prepared using an N,N-dimethylacrylamide (DMAA) system. The endothermic and exothermic peaks are related to the decomposition of organic matter and the reaction between pyrolytic carbon and impurity oxides in the sintering process. Multi-step heat preservation during the thermal degreasing process reduced the carbon content and defects. The α→β phase transformation and aspect ratio of grains changed from 89.2% to 4.84:1 at 1640 °C to 96.3% and 7.80:1 at 1700 °C, respectively. The relative density, hardness, fracture toughness, and thermal conductivity of the Si 3 N 4 samples reached 98.5%, 1353 HV, 8.51 MPa·m 1/2 , and 97.1 W·m −1 ·K −1 , respectively. Pyrolytic carbon can react with SiO 2 , which reduces the content of the glass phase in the green body and affects the dissolution and precipitation process and lattice oxygen content. In the structure of the Si 3 N 4 sample, carbon particles with sizes of 100–500 nm and near-spherical shapes were observed. Intergranular-phase YMgSi 2 O 5 N was formed during the sintering process, which was conducive to improving the thermal conductivity. This article uses lower temperature and no pressure conditions to prepare Si 3 N 4 ceramics, which can provide reference for batch and low-cost production.
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
·
2024
·
IF 5.1
Ning Sun,Tengpeng Wang,Yuhang Du,Xiaojun Ma,Wenkai Xin,Haochen Dang,Xuqiu Xie,Tao Wei,Qinggang Li
Si 3 N 4 ceramics pose a challenge when it comes to the preparation of light-curing pastes with high depth of cure, elevated solid content, and low viscosity. This challenge is primarily attributed to their inherent characteristics, including high absorbance, a high refractive index, and suboptimal sphericity. Consequently, the application of Si 3 N 4 ceramics in 3D printing remains a complex endeavor. To address the intricacies associated with 3D printing using Si 3 N 4 ceramics, our research focuses on the utilization of Tetramethylammonium Hydroxide (TMAH) for pH adjustment in Si 3 N 4 ceramics. This adjustment aims to enhance the stability, curing depth, and viscosity of the slurry. Subsequently, we employ this Si 3 N 4 light-curing slurry for 3D printing, followed by sintering the printed materials. The evaluation includes testing for porosity, density, and flexural strength of the samples. Notably, our efforts yield porous silicon nitride ceramics boasting an impressive density of 1.8299 g/cm 3 , porosity measuring 43.718%, and remarkable flexural strength amounting to 275 MPa.
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
HIGH PERFORMANCE POLYMERS
·
2022
·
IF 1.73
Weichu Jia,Jingfei Shangguan,Feng Lang,Duxin Li,Haiyang Yang
Si3N4 whiskers were modified with triethoxysilane as a means to improve the interfacial interaction with a poly-amide imide (PAI). The Si3N4/PAI composites were prepared by in-situ polymerization as an approach to improve the friction behavior and mechanical properties in order to meet the performance needs of electrical transformers and motors in harsh environments. 4,4′-diamino diphenyl ether, m-phenylenediamine, triethylamine, trimellitic anhydride chloride, and Si3N4 whiskers were used to manufacture Si3N4/PAI composite, which was then characterized for friction and mechanical behavior. The research showed that the addition of Si3N4 whiskers improved the mechanical properties and friction properties of PAI. When the whisker content was 10 wt%, the tensile strength of the composite was 137.5 MPa, which is 15% higher than pure PAI, and the wear rate was 0.69 × 10-8 g/N·m, which is 57% lower than pure PAI, and the friction coefficient was 0.47, which was an increase of 9%. In aerospace, machinery, and transportation applications, these materials may have better performance due to their improved combination of properties.
研究领域:
材料科学
·
摩擦学
✓ 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）