Materials Express
·
2020
·Vol. 10
·期 6
·928-933
·
IF 1.65
Tian Liang,Hou Qinglin,Wang Yingxia,Hou Yihui
Si3N4 ceramic has excellent properties such as high temperature resistance, high hardness, and high thermal stability, but it has the disadvantages of high hardness and brittleness and difficulty in later processing. In this paper, ZrO2 was used as toughening
phase, and ZrO2 toughened Si3N4 ceramics was prepared by injection molding. The effects of ZrO2 sintering temperature and content on the mechanical properties and fracture morphology were studied. Experiments show that when the ZrO2 content
is 10 wt.% and the sintering temperature reaches 1650 °C, the bending strength and fracture toughness of Si3N4 ceramics reach the maximum at the same time, which are 767 MPa and 8.7 MPa·m1/2, respectively. The density is high. XRD analysis revealed
that if the sintering temperature is too high, the ZrO2/Si3N4 system will generate a large number of ZrN impurity phases that cannot be phase-transformed, which ultimately affects the ceramic properties. According to fracture morphology, the toughening mechanism
of ZrO2 is stress-induced phase transition.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2023
·
IF 5.2
Yi-Ran Li,Ying-Ming Li,Wen-Juan Hu,Dan-Ping Zhu,Jose Hobson,Antonio Vázquez-López,De-Yi Wang
Epoxy resin (EP) is one kind of widely applicated thermosetting resin with excellent manufacturability, mechanical performance and chemical resistance, but its flammability seriously limited its widely application. In this work, the flame-retarding curing agent (BIPD) with was prepared by a simple one-step substitution reaction between benzimidazole (BI) and phenylphosphonyl dichloride (PD). When the mass fraction of BIPD is 10 %, the flexural strength and impact strength are 174.7 MPa and 14.9 KJ/m 2 , respectively, which are 15.5 % and 69 % higher than those of EP/BI 10 . The EP/BIPD 10 passed the UL-94 V-0 rating with a limiting oxygen index (LOI) reaching to 33 %. Meanwhile, the peak of heat release rate (PHRR) and total heat release rate (THR) of EP/BIPD 10 decreased by 50.2 % and 37.8 %, the total smoke production (TSP) and the mass percentage of residues increased by 10.4% and 204.1 % than that of EP/BI 10 in the cone calorimeter (CC) measurement, showing a jointly flame-retarding process in the condensed and gas phase. Furthermore, the results of Raman spectrum , the thermogravimetric infrared spectroscopy (TG-FTIR) and pyrolysis-gas chromatography/mass spectrometry (PY-GC/MS) confirmed the conclusion.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Jian Qiao,Kehui Lin,Renqiang Shi
To improve the properties of SiC fiber-reinforced ceramic-matrix composites for potential use as radar-absorbing materials, La 2 Ti 2 O 7 interphase was dip-coated on the surface of the SiC fibers, and the SiC f /NBAS composites were then prepared. The pristine SiC fibers with relatively high electrical resistivity were mainly composed of amorphous Si x C y O and a small amount of β -SiC and free carbon. A weak La 2 Ti 2 O 7 interphase improved the flexural strength and toughness of the composites due to the fiber pull-out and crack deflection. The measured room-temperature complex permittivity of the composites increased, and the dielectric loss was greater than that of the pristine SiC fibers owing to the production of excess free carbon in the degradation of SiC fibers during the preparation of SiC f /NBAS composites. The excess free carbon with higher electrical conductivity was also believed to play a significant part in the increase of dielectric permittivity of the composites with the increasing heat-treatment temperatures even below 1000 °C. A dual-layer structure was designed to expand the bandwidth for microwave absorption.
研究领域:
材料科学
·
复合材料
·
电磁学
✓ 已验证
DOI
高影响因子
Silicon
·
2024
·
IF 2.8
Huang Yunzhi,Li He,Colombo Paolo
3D printed silica ceramics have the advantages of low thermal expansion coefficient, high thermal stability, easy removal, etc., and are widely used in ceramic core manufacturing. However, in the sintering stage, silica often cracks due to shrinkage and phase transformation, which seriously affects the mechanical properties of the material. The impregnation of alumina sol can promote the formation of cristobalite phase in ceramics, and the mechanical properties of ceramics can be improved with appropriate amount of cristobalite. In this study, 3D printed silica ceramics were impregnated with alumina sol, and the effects of pH value and the concentration of alumina in the sol on the properties of the samples were investigated. When pH was 2.5, the mechanical properties of alumina sol impregnated samples reached a flexural strength of 24.98 ± 0.93 MPa, with a bulk density of 1.70 ± 0.01 g/cm 3 , and an open porosity of 25.82 ± 0.33%. When the ratio of alumina sol to silica sol was 3:1, the mechanical properties of alumina sol impregnated ceramics reached the maximum, with a flexural strength of 33.85 ± 1.69 MPa, a bulk density of 1.73 ± 0.01 g/cm 3 , and an open porosity of 24.02 ± 0.72%.
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
Yulong She,Jie Tang,Chaoyang Wang,Zhicheng Wang,Zhengren Huang,Yong Yang
Silicon carbide (SiC) ceramic stands as a critical material in the realm of high-performance engineering ceramics . However, Crafting SiC ceramics with intricate structures and superior mechanical properties presents notable challenges in shaping, sintering, and processing. Binder jetting (BJ) additive manufacturing has the outstanding advantages of high forming efficiency and no thermal deformation , especially suitable for printing complex structure SiC components.; however, BJ printed green bodies often exhibit low density, resulting in high residual silicon content and diminished strength of the final components. In this work, we introduce a novel strategy to fabricate high-strength SiC components with complex geometries by improving the density of printed SiC green bodies. This method involves modifying the morphology of SiC powder through the molten salt method to increase the density of BJ 3D printed green bodies from 1.24 ± 0.13 g/cm³ to 2.01 ± 0.03 g/cm³, followed by a reactive melt infiltration process. The resulting RB-SiC ceramics display exceptional flexural strength , averaging 280.60 ± 33.05 MPa, and an elastic modulus of 294.67 ± 4.90 GPa. These values represent some of the highest for flexural strength and elastic modulus reported among 3D-printed SiC composites. With its robust mechanical performance and streamlined fabrication process, this strategy holds substantial promise for the production of structural SiC ceramics.
研究领域:
材料科学
·
增材制造
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Baiyun Cheng,Qilai Zhou,Shengming Yin,Kaixuan Zhu,Yasuhisa Oya
Lithium ceramics are regarded as potential candidates for tritium breeding in fusion reactors. Lead (Pb) was added to the ceramic to improve the strength and tritium release properties. The Li 2 TiO 3 -0.5Li 4 SiO 4 –Pb ceramic powders with the Pb contents of 5 wt% and 20 wt% were prepared by microwave-induced solution combustion synthesis . It was confirmed that the Pb was in the form of the Li 2 PbO 3 phase in the powders. The Li 2 TiO 3 , Li 4 SiO 4 , and Li 2 PbO 3 crystallites were composited at nanoscale level, which was confirmed by the transmission electron microscopy (TEM). During high-temperature sintering, the Li 2 PbO 3 was transformed into PbO, which facilitated the densification process at low temperatures. The chemical state in the sintered body was characterized by X-ray photoelectron spectroscopy (XPS) with 3 keV Ar + sputtering. The binding energies for Pb were 137.2 and 142.2 eV. There was almost no change in peak position during Ar + sputtering, showing that Pb was firmly adherent with oxygen atoms. Besides, the as-synthesized powders were used for the pebble fabrication. The average crush load of Li 2 TiO 3 -0.5Li 4 SiO 4 –20%Pb pebbles sintered at 1223 K was 124 N, which was much higher than that without Pb addition. It was proved that the crush load increased almost linearly with the increase in the size of the pebbles. Thus, the bending strength of the sintered ceramic body was used to evaluate the mechanical properties. Further, the grain growth kinetics was studied. It was confirmed that the Pb addition reduced the activation energy of grain growth, which realized the densification of the ceramic pebbles at low temperatures.
研究领域:
材料科学
·
核能工程
✓ 已验证
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
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Yang Wu,Ruiming Yin,Kai Xu,Jing Li
Hydrolyzed AlN in traditional raw materials is not suitable for aqueous gel casting using DMAA (N,N-dimethylacrylamide) gelling agents. Therefore, a new hydrolysis-resistant AlCN was studied to replace hydrolyzed AlN. By adding the low toxicity organic monomers DMAA and MBAM (methylenebisacrylamide), the rheological properties of the slurry obtained under different conditions and the solidification and sintering properties of Sialon ceramics were studied. The results show that the best rheological properties can be obtained when the ball milling time is between 8 and 10 h and when the dispersant dose is 2%. When the ratio of DMAA to MBAM is 14:1, the flexural strength of the green body reaches a maximum of 15.29 MPa. When the sintering temperature increases from 1600 °C to 1750 °C, the density, Vickers hardness and fracture toughness of the sintered body gradually increase, reaching 3.195 g/cm 3 , 1549 HV, and 9.29 MPa m 1/2 , respectively. The flexural strength of the sintered body first increases and then decreases, reaching a maximum of 415 MPa at 1650 °C and a minimum of 303 MPa at 1750 °C.
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
Materials
·
2021
·Vol. 14
·期 6
·1347
·
IF 3.623
Moses Karakouzian,Visar Farhangi,Marzieh Ramezani Farani,Alireza Joshaghani,Mehdi Zadehmohamad,Mohammad Ahmadzadeh
Considering the remarkable characteristics of nanomaterials, previous research studies investigated the effects of incorporating different types of these materials on improving the concrete properties. However, further studies are required to evaluate the complementary hybridization and synergistic influence of nanomaterials. In this research, the combined effect of adding nano silica particles (NS) and multi-walled carbon nanotubes (MWCNT) on enhancing both the compressive and flexural strengths of the cement paste was investigated. Moreover, the morphology of the interface between cement paste and aggregates was studied by scanning electron microscopy (SEM). The mixtures were prepared using three different portions of MWCNT and NS. Electron microscopy images indicated a uniform distribution of nanoparticles in the cement matrix, enhanced hydration reactions, and increased density. Based on the experiments’ outcomes, the combined utilization of silica and carbon nanomaterials in the cement paste did not necessarily result in the maximum compressive and flexural strengths. Furthermore, it was observed that the use of higher percentages of pristine NS in the absence of MWCNT can lead to further enhancement of strength properties of the cement paste.Keywords:silica nanoparticles;carbon nanotube;compressive strength;flexural strength
研究领域:
土木工程
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Yuelong Wang,Jianjun Tian,Haoyang Wu,Baorui Jia,Xingyu Li,Yiming Zhang,Zhirui Zhang,Xuanhui Qu,Mingli Qin
Si 3 N 4 ceramics were prepared using novel two-step sintering method by mixing α -Si 3 N 4 as raw material with nanoscale Y 2 O 3 –MgO via Y(NO 3 ) 3 and Mg(NO 3 ) 2 solutions. Si 3 N 4 composite powders with in situ uniformly distributed Y 2 O 3 –MgO were obtained through solid–liquid (SL) mixing route. Two-step sintering method consisted of pre-deoxidization at low temperature via volatilization of in situ-formed MgSiO 3 and densification at high temperature. Variations in O, Y, and Mg contents in Si 3 N 4 –Y 2 O 3 –MgO during first sintering step are discussed. O and Mg contents decreased with increasing temperature because SiO 2 on Si 3 N 4 surface reacted with MgO to form low-melting-point MgSiO 3 compound, which is prone to volatilize at high temperature. By contrast, Y content hardly changed due to high-temperature stability of Y–Si–O–N quaternary compound. In the second sintering step, skeleton body was densified, and the formation of Y 2 Si 3 O 3 N 4 secondary phase occurred simultaneously. Two-step sintered Si 3 N 4 ceramics had lower total oxygen content (1.85 wt%) than one-step sintered Si 3 N 4 ceramics (2.51 wt%). Therefore, flexural strength (812 MPa), thermal conductivity (92.1 W/m·K), and fracture toughness (7.6 MPa⋅m 1/2 ) of Si 3 N 4 ceramics prepared via two-step sintering increased by 28.7%, 16.9%, and 31.6%, respectively, compared with those of one-step sintered Si 3 N 4 ceramics.
研究领域:
材料科学
·
机械工程
✓ 已验证
DOI
高影响因子
Journal of Advanced Ceramics
·
2022
·Vol. 11
·期 4
·656-664
·
IF 11.534
Xu Songsong,Zhou Xiaonan,Zhi Qiang,Gao Junjie,Hao Liucheng,Shi Zhongqi,Wang Bo,Yang Jianfeng,Ishizaki Kozo
Inspired by the transport behavior of water and ions through the aligned channels in trees, we demonstrate a facile, scalable approach for constructing biomorphic cellular Si 3 N 4 ceramic frameworks with well-aligned nanowhisker arrays on the surface of directionally aligned microchannel alignments. Through a facile Y(NO 3 ) 3 solution infiltration into wood-derived carbon preforms and subsequent heat treatment, we can faultlessly duplicate the anisotropic wood architectures into free-standing bulk porous Si 3 N 4 ceramics. Firstly, α-Si 3 N 4 microchannels were synthesized on the surface of C B -templates via carbothermal reduction nitridation (CRN). And then, homogeneous distributed Y−Si−O−N liquid phase on the walls of microchannel facilitated the anisotropic β-Si 3 N 4 grain growth to form nanowhisker arrays. The dense aligned microchannels with low-tortuosity enable excellent load carrying capacity and thermal conduction through the entire materials. As a result, the porous Si 3 N 4 ceramics exhibited an outstanding thermal conductivity (TC, k R ≈ 6.26 W·m −1 ·K −1 ), a superior flexural strength (σ L ≈ 29.4 MPa), and a relative high anisotropic ratio of TC ( k R / k L = 4.1). The orientation dependence of the microstructure-property relations may offer a promising perspective for the fabrication of multifunctional ceramics.
研究领域:
材料科学
·
仿生学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Jie Zhang,Kang-Bo Yu,Jia-Min Wu,Chun-Sheng Ye,Wen Zheng,Heng Liu,Shi-Feng Wen,Chun-Ze Yan,Yu-Sheng Shi
SiO 2 -based ceramic cores are widely used in the preparation of gas turbine engine hollow blades due to their excellent chemical stability and easy removal after casting. In this paper, ZrSiO 4 reinforced SiO 2 -based ceramics were fabricated using digital light processing (DLP) technology. The results showed that the addition of ZrSiO 4 reduced the cure depth due to its high UV light absorptivity and refractive index . When the content of ZrSiO 4 increased to 15 wt%, the cristobalite content reached the maximum, and radial shrinkage reached the minimum of 1.4%. ZrSiO 4 grains could hinder the propagation of cracks, enhancing the room-temperature flexural strength . At 1550 °C, fracturing across SiO 2 grains in SiO 2 -based ceramics led to the great improvement of high-temperature flexural strength. When the content of ZrSiO 4 reached 15 wt%, the flexural strength at room temperature and high temperature was 11.5 MPa and 36.7 MPa, respectively. Therefore, the SiO 2 -based ceramics prepared using DLP technology have good room temperature and high temperature properties, and are expected to be used for hollow blade casting.
研究领域:
材料科学
·
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）