The Experts below are selected from a list of 40857 Experts worldwide ranked by ideXlab platform
Dongliang Jiang - One of the best experts on this subject based on the ideXlab platform.
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Near zero shrinkage porous Al2O3 prepared via 3D-printing and Reaction Bonding
Materials Letters, 2015Co-Authors: Dongxu Yao, Yu-ping Zeng, Dongliang Jiang, Cynthia M. Gomes, Jens Günster, Jürgen G. HeinrichAbstract:Abstract Porous Al 2 O 3 with high porosity (~45%), remarkable flexural strength (~70 MPa), and low dimensional change (~1–2%), was produced by indirect 3D printing and Reaction Bonding. Coarse Al with good flowability was carried out printing green body. The green body was heat treated to get fully oxidized, volume expansion during oxidation simultaneously formed strong neck Bonding, not only brought good strength, but also restricted shrinkage. Porous Al 2 O 3 with architecture of macro pores designed by 3D printing and micro pores in the strut formed by packing of particles was obtained. The near zero shrinkage can facilitate precise design of product with complex shape.
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development of sic sic joint by Reaction Bonding method using sic c tapes as the interlayer
Journal of The European Ceramic Society, 2012Co-Authors: Zhaohua Luo, Dongliang Jiang, Jingxian Zhang, Qingling Lin, Zhongming Chen, Zhengren HuangAbstract:Abstract SiC/C tapes with different compositions and thicknesses were used to join pressureless sintered silicon carbide ceramics by Reaction Bonding method. The microstructure of the joints and the influences of joint thickness and residual silicon content in joint layer on the 4-point flexural strength of as joined SiC ceramics have been investigated. Specimens with high flexural strength can be achieved through the control of the composition and the thickness of the joint layer. The highest flexural strength of the joined specimens with the joint thickness of 13 μm can reach 346 ± 35 MPa and 439 ± 31 MPa at room temperature and 1250 °C, respectively. The microstructure development and the Reaction Bonding mechanism were also studied.
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Development of SiC–SiC joint by Reaction Bonding method using SiC/C tapes as the interlayer
Journal of the European Ceramic Society, 2012Co-Authors: Zhaohua Luo, Dongliang Jiang, Jingxian Zhang, Qingling Lin, Zhongming Chen, Zhengren HuangAbstract:Abstract SiC/C tapes with different compositions and thicknesses were used to join pressureless sintered silicon carbide ceramics by Reaction Bonding method. The microstructure of the joints and the influences of joint thickness and residual silicon content in joint layer on the 4-point flexural strength of as joined SiC ceramics have been investigated. Specimens with high flexural strength can be achieved through the control of the composition and the thickness of the joint layer. The highest flexural strength of the joined specimens with the joint thickness of 13 μm can reach 346 ± 35 MPa and 439 ± 31 MPa at room temperature and 1250 °C, respectively. The microstructure development and the Reaction Bonding mechanism were also studied.
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fabrication and characterization of cordierite bonded porous sic ceramics
Ceramics International, 2009Co-Authors: Shifeng Liu, Yu-ping Zeng, Dongliang JiangAbstract:Abstract A Reaction Bonding technique was used for the preparation of cordierite-bonded porous SiC ceramics in air from α-SiC, α-Al 2 O 3 and MgO, using graphite as the pore-forming agent. Graphite was burned out to produce pores and the surface of SiC was oxidized to SiO 2 at high temperature. With further increasing the temperature, SiO 2 reacted with α-Al 2 O 3 and MgO to form cordierite. SiC particles were bonded by the cordierite and oxidation-derived SiO 2 . The Reaction Bonding characteristics, phase composition, open porosity, pore size distribution and mechanical strength as well as microstructure of porous SiC ceramics were investigated. The pore size and porosity were strongly dependent, respectively, on graphite particle size and volume fraction. The porous SiC ceramics sintered at 1350 °C for 2 h exhibited excellent combination properties, the flexural strength of 26.0 MPa was achieved at an open porosity of 44.51%.
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In-situ Reaction Bonding of porous SiC ceramics
Materials Characterization, 2008Co-Authors: Shuqiang Ding, Yu-ping Zeng, Dongliang JiangAbstract:Abstract Porous SiC ceramics were prepared by an in-situ Reaction Bonding process from SiC, Al 2 O 3 and graphite in air at 1400–1550 °C. The Reaction Bonding behavior during the sintering was studied. The surface of SiC particles is oxidized to amorphous silica above 750 °C. When the sintering temperature reaches 1100 °C, the amorphous silica begins to be crystallized to cristobalite. After 1400 °C, the oxidation-derived silica reacts with Al 2 O 3 to form mullite. Porous SiC ceramics are bonded by the silica and mullite. In addition, the effects of sintering temperatures on the Reaction Bonding behavior, open porosity and flexural strength were investigated.
Zhengren Huang - One of the best experts on this subject based on the ideXlab platform.
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Joining of the Cf/SiC composites by a one-step Si infiltration Reaction Bonding
Materials Characterization, 2019Co-Authors: Bingbing Pei, Yunzhou Zhu, Zhengren HuangAbstract:Abstract An improved joining technique by Reaction bonded technology was studied. The final densification and joining of the Reaction-sintered composites were simultaneously completed in the Reaction Bonding process by one-step Si infiltration process. This method achieves joints with strong interfacial Bonding and high flexural strength. The joint obtained by the one-step silicon infiltration Reaction has a more uniform microstructure, the joint flexural strength is increased to 203 MPa, and retention rate of the flexural strength is 96%, which is comparable to the flexural strength of the C f /SiC substrate. The microstructure and interfacial evolution mechanism of the interlayer were discussed. The results show that a transition layer of 2–3 μm transition layer formed between the interlayer and the C f /SiC substrate, which is composed of SiC crystal grains of about 0.5–1 μm. The formation of the transition layer is due to the carbon concentration difference at the interface between interlayer and substrate, resulting in the diffusion of carbon during the Si C Reaction.
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si sic coated cf sic composites via tape casting and Reaction Bonding the effect of carbon content
Ceramics International, 2016Co-Authors: Shengxing Song, Yinsheng Li, Yihua Huang, Guofeng Cheng, Zhengren HuangAbstract:Abstract In this paper, a novel surface modification method for C f /SiC composites is proposed. Si/SiC coating on C f /SiC composites is prepared by tape casting and Reaction Bonding method. The effects of carbon content on the rheological property of the slurries along with the microstructure of the sintered coatings are investigated. The best result has been obtained by infiltrating liquid silicon into a porous green tape with a carbon density of 0.84 g/cm 3 . In addition, the effect of sintering parameters on the phase composition of the coatings is studied. Dense Si/SiC coating with high density as well as strong Bonding onto the substrate is obtained. This Si/SiC coating exhibits an excellent mechanical property with HV hardness of 16.29±0.53 GPa and fracture toughness of 3.01±0.32 MPa m 1/2 . Fine surface with roughness (RMS) as low as 2.164 nm is achieved after precision grinding and polishing. This study inspires a novel and effective surface modification method for C f /SiC composites.
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development of sic sic joint by Reaction Bonding method using sic c tapes as the interlayer
Journal of The European Ceramic Society, 2012Co-Authors: Zhaohua Luo, Dongliang Jiang, Jingxian Zhang, Qingling Lin, Zhongming Chen, Zhengren HuangAbstract:Abstract SiC/C tapes with different compositions and thicknesses were used to join pressureless sintered silicon carbide ceramics by Reaction Bonding method. The microstructure of the joints and the influences of joint thickness and residual silicon content in joint layer on the 4-point flexural strength of as joined SiC ceramics have been investigated. Specimens with high flexural strength can be achieved through the control of the composition and the thickness of the joint layer. The highest flexural strength of the joined specimens with the joint thickness of 13 μm can reach 346 ± 35 MPa and 439 ± 31 MPa at room temperature and 1250 °C, respectively. The microstructure development and the Reaction Bonding mechanism were also studied.
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Development of SiC–SiC joint by Reaction Bonding method using SiC/C tapes as the interlayer
Journal of the European Ceramic Society, 2012Co-Authors: Zhaohua Luo, Dongliang Jiang, Jingxian Zhang, Qingling Lin, Zhongming Chen, Zhengren HuangAbstract:Abstract SiC/C tapes with different compositions and thicknesses were used to join pressureless sintered silicon carbide ceramics by Reaction Bonding method. The microstructure of the joints and the influences of joint thickness and residual silicon content in joint layer on the 4-point flexural strength of as joined SiC ceramics have been investigated. Specimens with high flexural strength can be achieved through the control of the composition and the thickness of the joint layer. The highest flexural strength of the joined specimens with the joint thickness of 13 μm can reach 346 ± 35 MPa and 439 ± 31 MPa at room temperature and 1250 °C, respectively. The microstructure development and the Reaction Bonding mechanism were also studied.
Mark I. Jones - One of the best experts on this subject based on the ideXlab platform.
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wear behaviour and electrical conductivity of β sialon zrn composites fabricated by Reaction Bonding and gas pressure sintering process
Ceramics International, 2019Co-Authors: Li Yin, Wei Gao, Mark I. JonesAbstract:Abstract β-Sialon-ZrN composites with different levels of substitution and ZrN content have been formed by a process of Reaction Bonding and post gas pressure sintering, and the wear properties and electrically conductive properties have been investigated. The results showed that an appropriate higher sintering temperature was beneficial for increasing wear resistance, and the composites with β-Sialon (Z = 1) had better wear properties than those with β-Sialon (Z = 4). The incorporation of the ZrN particles was observed to have an effect on the wear properties of the composites. The best wear properties was observed for the composites sintered at 1700 °C with lowest wear rate of 2.4 × 10−5 mm3N−1m−1 for β-Sialon (Z = 1)-20 wt% ZrN and 5.0 × 10−4 mm3N−1m−1 for β-Sialon (Z = 4)-30 wt% ZrN, respectively. The wear resistance was influenced by numerous factors, including phase composition, microstructure, hardness and fracture toughness, and the material was mainly removed by delamination, micro-fracture and micro-cracks. At a given ZrN content, a continuous electrically conductive network was formed and had an effect on the electrical resistivity of the composites, where the electrical resistivity decreased from around 1012 Ω∙m for monolithic β-Sialon to around 10 Ω∙m for 23 vol% ZrN.
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The formation and properties of Sialon-ZrN composites produced by Reaction Bonding combined with post gas-pressure sintering
Ceramics International, 2018Co-Authors: Li Yin, Mark I. JonesAbstract:Abstract Sialon-ZrN composites have been fabricated by a combination of Reaction Bonding and post-gas-pressure sintering. Composites with different amount of ZrN were post sintered at 1600, 1700 and 1800 °C under a nitrogen pressure of 0.7 MPa for 6 h. The results showed that mass loss due to decomposition increased with increasing sintering temperature. The mass loss at 1600 and 1700 °C was comparable, and below 3% even for the highest ZrN content of 50 wt%, but ranged between 6% and 9% for samples post sintered at 1800 °C with 10–50 wt% ZrN. Composites sintered at 1700 °C had the highest relative density (> 97%) and lowest open porosity (
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Influence of additives and compositions on the nitridation and formation of SiAlONs produced by Reaction Bonding and silicothermal reduction
Journal of Asian Ceramic Societies, 2013Co-Authors: Yann Rouquié, Mark I. JonesAbstract:Abstract Precursor mixtures of β-SiAlON ( z = 1 and 4) and O-SiAlONs ( x = 0.05 and 0.2) have been prepared by both Reaction Bonding and silicothermal reduction techniques in a nitrogen atmosphere. The influence of the starting compositions and the use of different additives on the nitridation behavior and SiAlON phase formation have been studied. Most of the additive systems (ZrO 2 , Y 2 O 3 , Dy 2 O 3 , YAG and DyAG) enhanced the nitridation of Si while surprisingly CaO did not. In terms of the rare-earths, the enhanced nitridation was greater with the garnet phases than with the comparable oxide, and combinations of additives were essentially a sum of the individual effects. Although, the use of CaO did not improve nitridation, it did lead to SiAlON formation at lower temperatures due to the formation of a low temperature eutectic liquid, and this was dependent on the starting powders with SiO 2 rich compositions mixtures giving greater SiAlON formation. For the β-SiAlON samples produced by silicothermal reduction, which have low SiO 2 contents, the use of rare-earths appears to catalyze the decomposition of mullite, resulting in greater SiAlON formation. This did not occur in samples with higher silica content since the rare-earth reacts preferentially with the starting powder.
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Formation and densification of SiAlON materials by Reaction Bonding and silicothermal reduction routes
IOP Conference Series: Materials Science and Engineering, 2011Co-Authors: Yann Rouquié, Mark I. JonesAbstract:Samples of β and O-sialon with different levels of substitution (i.e. z = 1 and 4 for β-sialon and x = 0.05 and 0.2 for O-sialon) have been synthesized by both Reaction Bonding and silicothermal reduction techniques in a nitrogen atmosphere. The possibility of obtaining dense sialon materials by these lower cost production methods has been investigated using a statistical design methodology. The influence of different parameters (temperature, gas pressure and additive type) on the densification and decomposition has been studied and will be discussed in this presentation.
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Fabrication of Elongated α‐SiAlON via a Reaction‐Bonding Process
Journal of the American Ceramic Society, 2004Co-Authors: Youichirou Kaga, Mark I. Jones, Kiyoshi Hirao, Shuzo KanzakiAbstract:A Reaction-Bonding process, which offers low sintering shrinkage and is a low-cost process, was applied to fabricate Y–α-SiAlON ceramics. The green compacts composed of Si, Y2O3, Al2O3, and AlN were nitrided and subsequently postsintered. Dense single-phase Y–α-SiAlON with elongated grain morphology could be achieved in the specimen postsintered at 1900°C. The material exhibited high hardness (1850 HV10) and high fracture toughness (5.1 MPa·m1/2).
Jamal Chaouki - One of the best experts on this subject based on the ideXlab platform.
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Novel fabrication route for porous silicon carbide ceramics through the combination of in situ polymerization and Reaction Bonding techniques
Journal of Applied Polymer Science, 2014Co-Authors: Omid Ebrahimpour, Babak Esmaeili, Lucie Griffon, Jamal Chaouki, Charles DuboisAbstract:For the first time, an in situ polymerization technique was applied to produce mullite-bonded porous SiC ceramics via a Reaction Bonding technique. In this study, SiC microsized particles and alumina nanopowders were successfully coated by polyethylene (PE), which was synthesized from the particle surface in a slurry phase reactor with a Ziegler–Natta catalyst system. The thermal studies of the resulting samples were performed with differential scanning calorimetry and thermogravimetric analysis. The morphology analysis obtained by transmission electron microscopy and scanning electron microscopy (SEM) confirmed that PE was successfully grafted onto the particle surface. Furthermore, the obtained porous ceramics were characterized in terms of their morphologies, phase composition, open porosity, pore size distribution, and mechanical strength. SEM observations and mercury porosimtery analysis revealed that the quality of the dispersion of nanosized alumina powder into the microsized SiC particles was strongly enhanced when the particles were coated by polymers with in situ polymerization. This resulted in a higher strength and porosity of the formed ceramic porous materials with respect to the traditional process. In addition, the X-ray diffraction results reveal that the amount of mullite as the binder increased significantly for the samples fabricated by this novel method. The effects of the sintering temperature, forming pressure, and polymer content on the physical and mechanical properties of the final porous ceramic were also evaluated in this study. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40425.
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fabrication of mullite bonded porous sic ceramics via a sol gel assisted in situ Reaction Bonding
Journal of The European Ceramic Society, 2014Co-Authors: Omid Ebrahimpour, Charles Dubois, Jamal ChaoukiAbstract:Abstract In the present work, mullite-bonded porous SiC ceramics were fabricated using Reaction Bonding techniques. The morphologies, phase composition, open porosity, pore size distribution and mechanical strength of porous ceramics were examined as a function of alumina sources (calcined nano-sized alumina powder and alumina sol prepared from hydrolysis of aluminum isopropoxide) and contents. It was found that the addition of alumina in powder form effectively enhanced the strength and decreased the porosity. In contrast, when alumina was added in sol form, a reverse effect was observed. Moreover, it was revealed that when a portion of calcined alumina was replaced by alumina sol, the mechanical properties improved significantly (more than 30%) as well as porosity compared to the traditional method. Pore size distribution analysis showed that the dispersion of nanosize alumina powder and SiC micro-particles in alumina sol is strongly improved compared to mixing in ethanol.
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Novel fabrication route for porous silicon carbide ceramics through the combination of in situ polymerization and Reaction Bonding techniques
Journal of Applied Polymer Science, 2014Co-Authors: Omid Ebrahimpour, Babak Esmaeili, Lucie Griffon, Jamal Chaouki, Charles DuboisAbstract:For the first time, an in situ polymerization technique was applied to produce mullite-bonded porous SiC ceramics via a Reaction Bonding technique. In this study, SiC microsized particles and alumina nanopowders were successfully coated by polyethylene (PE), which was synthesized from the particle surface in a slurry phase reactor with a Ziegler–Natta catalyst system. The thermal studies of the resulting samples were performed with differential scanning calorimetry and thermogravimetric analysis. The morphology analysis obtained by transmission electron microscopy and scanning electron microscopy (SEM) confirmed that PE was successfully grafted onto the particle surface. Furthermore, the obtained porous ceramics were characterized in terms of their morphologies, phase composition, open porosity, pore size distribution, and mechanical strength. SEM observations and mercury porosimtery analysis revealed that the quality of the dispersion of nanosized alumina powder into the microsized SiC particles was strongly enhanced when the particles were coated by polymers with in situ polymerization. This resulted in a higher strength and porosity of the formed ceramic porous materials with respect to the traditional process. In addition, the X-ray diffraction results reveal that the amount of mullite as the binder increased significantly for the samples fabricated by this novel method. The effects of the sintering temperature, forming pressure, and polymer content on the physical and mechanical properties of the final porous ceramic were also evaluated in this study. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40425.
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Fabrication of mullite-bonded porous SiC ceramics via a sol–gel assisted in situ Reaction Bonding
Journal of the European Ceramic Society, 2014Co-Authors: Omid Ebrahimpour, Charles Dubois, Jamal ChaoukiAbstract:Abstract In the present work, mullite-bonded porous SiC ceramics were fabricated using Reaction Bonding techniques. The morphologies, phase composition, open porosity, pore size distribution and mechanical strength of porous ceramics were examined as a function of alumina sources (calcined nano-sized alumina powder and alumina sol prepared from hydrolysis of aluminum isopropoxide) and contents. It was found that the addition of alumina in powder form effectively enhanced the strength and decreased the porosity. In contrast, when alumina was added in sol form, a reverse effect was observed. Moreover, it was revealed that when a portion of calcined alumina was replaced by alumina sol, the mechanical properties improved significantly (more than 30%) as well as porosity compared to the traditional method. Pore size distribution analysis showed that the dispersion of nanosize alumina powder and SiC micro-particles in alumina sol is strongly improved compared to mixing in ethanol.
Shuqiang Ding - One of the best experts on this subject based on the ideXlab platform.
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In-situ Reaction Bonding of porous SiC ceramics
Materials Characterization, 2008Co-Authors: Shuqiang Ding, Yu-ping Zeng, Dongliang JiangAbstract:Abstract Porous SiC ceramics were prepared by an in-situ Reaction Bonding process from SiC, Al 2 O 3 and graphite in air at 1400–1550 °C. The Reaction Bonding behavior during the sintering was studied. The surface of SiC particles is oxidized to amorphous silica above 750 °C. When the sintering temperature reaches 1100 °C, the amorphous silica begins to be crystallized to cristobalite. After 1400 °C, the oxidation-derived silica reacts with Al 2 O 3 to form mullite. Porous SiC ceramics are bonded by the silica and mullite. In addition, the effects of sintering temperatures on the Reaction Bonding behavior, open porosity and flexural strength were investigated.
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fabrication of mullite bonded porous silicon carbide ceramics by in situ Reaction Bonding
Journal of The European Ceramic Society, 2007Co-Authors: Shuqiang Ding, Yu-ping Zeng, Sumin Zhu, Dongliang JiangAbstract:Abstract An in situ Reaction Bonding technique was developed to fabricate mullite-bonded porous silicon carbide (SiC) ceramics in air from SiC and α-Al 2 O 3 , using graphite as the pore-former. Graphite is burned out to produce pores and the surface of SiC is oxidized to SiO 2 at high temperature. With further increasing the temperature, the amorphous SiO 2 converts into cristobalite and reacts with α-Al 2 O 3 to form mullite (3Al 2 O 3 ·2SiO 2 ). SiC particles are bonded by the mullite and oxidation-derived SiO 2 to obtain porous SiC ceramics. The Reaction Bonding behavior, open porosity, pore size distribution and mechanical strength of porous SiC ceramics were investigated as a function of the sintering temperature, forming pressure and graphite content. In addition, the phase composition and microstructure were also studied.
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low temperature fabrication of porous sic ceramics by preceramic polymer Reaction Bonding
Materials Letters, 2005Co-Authors: Shuqiang Ding, Hongan Xi, Ruoding WangAbstract:Preceramic polymer polycarbosilane (PCS) and silicon carbide (SiC) powders were adopted as the starting materials for the fabrication of porous SiC ceramics. During the heat treatment process, PCS experienced an organic–inorganic transformation and acted as the Bonding material between SiC particles at a low temperature of 1100 °C. The particle size of starting SiC powders and PCS content can control the pore size distribution and porosity. Fracture strength increases with higher content of PCS. Moreover, the as-fabricated porous SiC ceramics exhibit a low average coefficient of thermal expansion (CTE) of 3.4×10−6/K from room temperature to 800 °C.
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In Situ Reaction Synthesis of Porous Silica-Matrix Ceramics
Key Engineering Materials, 2005Co-Authors: Shuqiang Ding, Dongliang Jiang, Sumin ZhuAbstract:A novel technique was developed to synthesize porous silica–matrix ceramics from silicon carbide and alumina with an Y2O3 addition, using pine sawdust as a pore former. The porous ceramics were fabricated at temperatures of 1300–1500 oC in air by a Reaction–Bonding process based on two Reactions: (1)SiC+2O2→SiO2+CO2 (Oxidation) and (2)2SiO2+3Al2O3→3Al2O3·2SiO2 (Mullitization). Reaction–Bonding behavior, mechanical property and open porosity were investigated as a function of Y2O3 content as well as sintering temperature and holding time. Moreover, phase composition and microstructure of the porous silica–matrix ceramics were studied by X–ray diffraction (XRD) and scanning electron microscopy (SEM).
