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
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陶瓷工程
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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
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Shuang Yin,Limei Pan,Lin Guo,Yun Liu,Yongbao Feng,Tai Qiu,Jian Yang
A low-toxic and water-soluble monomer N, N-dimethylacrylamide (DMAA) was employed as a gelling agent in the gelcasting of porous Si 3 N 4 ceramics. The process conditions and composition for slurry preparation (with a solid loading of 36 vol%), the consolidation and sintering of green bodies were investigated and optimized. The effects of various factors such as zeta potential , pH value of the premix solution, dispersant dosage and ball milling time on the rheological properties of the slurries were investigated. The results suggest that the best rheological properties (66.5 mPa.s at a shear rate of 96.3 s −1 ) of the slurries were obtained when pH value ranged between 9 and 11, dispersant dosage reached 1 wt%, and ball milling time was 6 h. All the as-prepared green bodies showed a homogeneous microstructure and high flexural strength ≥ 26 MPa with a maximum up to 46.3 MPa when the ratio of DMAA to MBAM, initiator dosage, polymerization temperature and time were 14, 1 wt%, 70 °C and 90 min, respectively. The sintered bodies had a homogeneous microstructure, excellent and regulatable properties, a flexural strength of 216.3–327.3 MPa, and a porosity of 39.6–29.1% by varying the sintering temperature from 1710 °C to 1810 °C and the holding time from 1 h to 3 h. The superior comprehensive effect makes DMAA a promising candidate for an environmentally friendly gelling agent in gelcasting of porous Si 3 N 4 ceramics.
研究领域:
材料科学
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陶瓷工程
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产品关联
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 15
·8415-8425
·
IF 3.049
Jing Li,Chuanfu Zhang,Ruiming Yin,Wenhai Zhang
In this work, the pyrolysis characteristics of a low-toxic N,N-dimethylacrylamide (DMAA) gel polymer was investigated through nonisothermal thermogravimetry (TG) and TG-FTIR analyses. Moreover, the thermal debinding kinetics of gelcast SiAlON ceramic parts was studied through three different kinetic models: the Coats–Redfern (C–R) method, distributed activation energy model (DAEM) and three-Gaussian-DAEM-reaction model (3-DAEM). The rationality and adaptability of the three models to the thermal debinding kinetics study were analyzed by comparison with experimental data. The results showed that three mass loss zones were observed in the temperature ranges of 100–320 °C, 320–520 °C and 520–600 °C, respectively, and the main pyrolysis gas products were CO2, H2O and CH4. The conversion rate (α) curves calculated by 3-DAEM were more consistent with the experimental values than those calculated with the C–R and DAEM methods. The fitting quality parameter (Fit%) was less than 2.63%, and the reaction rate (dα/dT) curves calculated by 3-DAEM were bimodal distribution curves, which were in good agreement with the experimental results. The kinetic parameters (E0,i, k0,i and σi) of the global thermal debinding process calculated by 3-DAEM were 116.00–145.79 kJ mol−1, 1.10 × 109 s−1 and 1.67–43.25 kJ mol−1, respectively. It is anticipated that the study achievements can be used to help predict the thermal debinding behavior and design a reasonable debinding technology for the gelcasting of ceramic parts.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Shuang Yin,Limei Pan,Xia Fang,Yufeng Li,Yanpu Li,Yongbao Feng,Tai Qiu,Jian Yang
In this study, the low–toxicity monomer N, N–dimethylacrylamide (DMAA), serving as both gelling agent and pore–forming agent, was adopted to fabricate porous Si 3 N 4 ceramics with a regulatable microstructure and property by aqueous gelcasting. Results indicate that monomer content played an important role in regulating and optimizing the properties of sintered bodies. With increasing monomer content (5.94–30.69 wt%), both slurry viscosity (maximum 0.14 Pa s at 95.40 s −1 ) and green body strength (11.35–49.23 MPa) exhibited monotonic increasing trends, demonstrating superior mechanical properties to those obtained using the neurovirulent acrylamide (AM) gelling system. The increased monomer content not only improved porosity, but also promoted α→β–Si 3 N 4 transformation as well as β–Si 3 N 4 grain growth through enhancing the connectivity of interlocking pores and accelerating the vapor phase transport during liquid–phase sintering. These variations in phase composition and microstructure derived from the varied monomer content further resulted in monotonic changes in porosity (40.32–51.50%), mean pore size (0.27–0.38 μm), flexural strength (202.77–132.15 MPa), fracture toughness (2.93–2.32 MPa m 1/2 ), dielectric constant (3.48–2.78) and loss (3.52–3.09 × 10 −3 ) at 10 GHz for sintered bodies, displaying an excellent comprehensive properties. This study suggests a promising prospect for DMAA in preparation of high–performance porous Si 3 N 4 ceramics by aqueous gelcasting.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Shuang Yin,Limei Pan,Kai Huang,Tai Qiu,Jian Yang
Porous Si 3 N 4 ceramics with bimodal hierarchical pore structures were fabricated through combining aqueous gelcasting and adding pore–forming agent method wherein a low–toxic monomer N, N–dimethylacrylamide (DMAA) and spherical pore–forming agent polystyrene sphere (PS) were respectively applied. The results demonstrated that PS size and content played an important function in regulating microstructure and properties of slurries, green and sintered bodies. The slurry viscosity increased sharply with the introduction of fine PS and reached a maximum of 1.78 Pa⋅s when adopting 7 wt% PS with d 50 = 2.51 μm. Fine PS addition caused higher porosity in green bodies than coarse one, resulting in a significant reduction in bending strength from 28.50 MPa to 11.50 MPa, however, overall, demonstrating high enough strength for mechanical processing. The formed spherical pores from PS in ceramic matrix facilitated high porosity and highly crosslinked microstructure, thus contributing to lowering dielectric constant and loss. With PS size increasing, the dominant role in mechanical properties was transferred from porosity to microstructure, whilst dielectric properties were merely controlled by porosity and spherical pores. The porosity, bending strength, fracture toughness, dielectric constant and loss at 15 GHz varied in ranges of 36.34–52.91%, 258.42–101.21 MPa, 6.02–3.38 MPa⋅m 1/2 , 4.29–2.98 and 1.48–1.18 × 10 −3 , respectively, displaying an excellent comprehensive properties.
研究领域:
材料科学
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陶瓷工程
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2016
·Vol. 133
·期 33
·
IF 1.866
Xin Tang,Bin Yuan,Yuanguang Yang,Yingquan Xie
A new water-soluble polymer was prepared and evaluated as a filtrate reducer for oil well cementing. The filtrate reducer (WSP) was synthesized from 2-acrylamido-2-methylpropane sulfonic acid (AMPS), acrylic acid (AA), dimethyl acrylamide (DMAA), and sodium allylsulfonate (SA) by aqueous free radical polymerization. The synthesis conditions were optimized by orthogonal experiment. The molecule structure of the synthesized copolymer (WSP) was verified by Fourier transformer infrared spectrum (FTIR) and nuclear magnetic resonance hydrogen spectroscopy ( 1 H-NMR). The molecule weight of the synthesized copolymer was determined by gel permeation chromatography (GPC). The thermal stability of the synthesized copolymer was tested by thermogravimetry and differential thermogravimetry (TG and DTG). When the dosage of WSP is up to 3% in fresh water cement slurry, the FL API can be controlled within 58 mL. In 37% salt water cement slurry, the FL API can be controlled within 90 mL when the dosage of WSP is 5%. The thermal degradation of WSP is not obvious before 289 °C. Compared with a commercial filtrate reducer BS-100L and a reported copolymer HTF200C, the WSP has better performance. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43824.
研究领域:
材料科学
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石油工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Shuang Yin,Senchuan Jiang,Limei Pan,Chao Liu,Yongbao Feng,Tai Qiu,Jian Yang
In this work, Si 3 N 4 ceramics were fabricated through an aqueous gelcasting method using a low–toxic monomer called N, N–dimethylacrylamide (DMAA) followed by gas pressure sintering at 1850 °C for 2 h under 6 MPa N 2 atmosphere. The effect of solid loading on performance of slurries, green and sintered bodies was investigated systematically. The results show that the slurries with a solid loading as high as 50 vol% (viscosity 0.17 Pa.s at 100 s –1 ) were achieved. With the increase of solid loading (30–50 vol%), the green bodies exhibited a monotonically decreased, however high enough in general, flexural strength of 16.50–11.52 MPa, which was comparable to that of widely–used neurovirulent acrylamide (AM) gelling system. In regard to the sintered bodies, increasing solid loading significantly promoted sintering and improved mechanical properties and thermal conductivity as a result of the increased density, bimodal distribution structure, as well as suitable interfacial bonding strength . The best performance parameters of Si 3 N 4 ceramics, bulk density of 3.25 g/cm 3 , apparent porosity of 0.67%, flexural strength of 898.92 MPa, fracture toughness of 6.42 MPa m 1/2 , Vickers hardness of 2.81 GPa, and thermal conductivity of 34.69 W m –1 K –1 , were obtained at 50 vol% solid loading. This work renders low–toxic DMAA gelling system promising prospect in preparation of high–performance Si 3 N 4 ceramics by gelcasting.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 47
·27305-27317
·
IF 3.049
Jing Li,Jindi Huang,Ruiming Yin
This work aims to develop an effective method for investigating the multistage debinding kinetics and reaction mechanisms of removing N,N-dimethylacrylamide/N,N′-methylenebisacrylamide (DMAA/MBAM) polymer from gelcast ceramic parts. Thermogravimetry (TG) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to investigate the thermal degradation characteristics and the main compounds produced during the pyrolysis of DMAA/MBAM polymer within green components. A multi-stage parallel reaction model (M-PRM) was proposed to separate the overlapping peaks in the dα/dT curves. The kinetic parameters (activation energy E and pre-exponential factor k0) of each substage were calculated using model-free methods (Flynn–Wall–Ozawa, Starink, Friedman and Kissinger–Akahira–Sunose) and an activation energy variable model. In addition, the most appropriate kinetic mechanism function f(α) of each substage was analyzed and discussed via Málek's procedure and the Šesták–Berggren (SB) model. The results showed that the DMAA/MBAM polymer burnout in green components can be divided into three substages through a three-stage parallel reaction model (3-PRM). The values of E (Friedman method) for substages 1 to 3 were E(α) = 139.862 − 110.481α + 156.161α2 − 88.714α3 kJ mol−1, E(α) = 160.791 + 152.496α − 236.906α2 + 163.724α3 kJ mol−1 and E(α) = 72.132 + 452.830α − 669.039α2 + 507.015α3 kJ mol−1, respectively. The average values of E showed an increasing tendency from substages 1 to 3, and a kinetic compensation effect was also observed between the E and k0 in each substage. The kinetic mechanism analysis revealed that the reaction mechanisms for substages 1 to 3 were f(α) = (1 − α)0.668α3.049(−ln(1 − α))−3.874, f(α) = (1 − α)0.700α3.177(−ln(1 − α))−3.962 and f(α) = (1 − α)1.049α−0.161(−ln(1 − α))0.518, respectively. It is expected that the research results can be extended to investigate the multiplex debinding of binders or polymers for various colloidal molding techniques.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 52
·32988-32995
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IF 3.361
Yinlei Lin,Shuoqi Wang,Sheng Sun,Yaoheng Liang,Yisheng Xu,Huawen Hu,Jie Luo,Haichen Zhang,Guangji Li
Introducing double physical crosslinking reagents (i.e., a hydrophobic monomer micelle and the LAPONITE® XLG nano-clay) into the copolymerization reaction of hydrophilic monomers of N,N-dimethylacrylamide (DMAA) and acrylamide (AM) is reported here by a thermally induced free-radical polymerization method, resulting in a highly tough and rapid self-healing dual-physical crosslinking poly(DMAA-co-AM) hydrogel. The mechanical and self-healing properties can be finely tuned by varying the weight ratio of nanoclay to DMAA. The tensile strength and elongation at break of the resulting nanocomposite hydrogel can be modulated in the range of 7.5–60 kPa and 1630–3000%, respectively. Notably, such a tough hydrogel also exhibits fast self-healing properties, e.g., its self-healing rate reaches 48% and 80% within 2 and 24 h, respectively.
研究领域:
材料科学
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高分子化学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2017
·Vol. 44
·期 2
·1621-1626
·
IF 2.986
Lin Guo,Jian Yang,Yongbao Feng,Tai Qiu
In this study, high-performance aluminum nitride (AlN) samples were prepared by gelcasting based on a low-toxicity monomer and organic solvents . We prepared a 50 vol% solid content AlN suspension with a solvent ratio of 3:1, 6 wt% N,N-dimethylacrylamide (DMAA) and 0.15 wt% Polyethyleneimine (PEI); after degassing, low viscosity and high stability were observed. It was proven that the AlN green bodies exhibited a bending strength of 18.68 MPa, which met the requirements for machining. An optimum debinding process was developed and the TG-DSC curves showed that the AlN green bodies were heated at 1 °C/min from 450 to 800 °C. The relative density, apparent porosity , bending strength, and thermal conductivity of the AlN sintered bodies prepared by non-aqueous gelcasting were 98.5%, 0.22%, 310 MPa, and 159 W m −1 K −1 respectively, representing optimum conditions. The uniform miscrostructure of the sintered bodies was observed by SEM images.
研究领域:
材料科学
·
陶瓷与复合材料
·
先进制造
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Shuang Yin,Dongliang Mao,Limei Pan,Xia Fang,Yang Wang,Tai Qiu,Jian Yang
The porous SiC–Si 3 N 4 composite ceramics with good EMW absorption properties were prepared by combination of gelcasting and carbothermal reduction. The pre-oxidation of Si 3 N 4 powders significantly improved the rheological properties of slurries (0.06 Pa s at 103.92 s −1 ) and also suppressed the generation of NH 3 and N 2 from Si 3 N 4 hydrolysis and reaction between Si 3 N 4 and initiator APS, thereby reducing the pore defects in green bodies and enhancing mechanical properties with a maximum value of 42.88 MPa. With the extension of oxidation time from 0 h to 10 h, the porosity and pore size of porous SiC–Si 3 N 4 composite ceramics increased from approximately 41.86% and 1.0–1.5 μm to 46.33% and ~200 μm due to the production of CO, N 2 and gaseous SiO, while the sintering shrinkage decreased from 16.24% to 10.50%. With oxidation time of 2 h, the Si 2 N 2 O fibers formed in situ by the reaction of Si 3 N 4 and amorphous SiO 2 effectively enhanced the mechanical properties , achieving the highest flexural strength of 129.37 MPa and fracture toughness of 4.25 MPa m 1/2 . Compared with monolithic Si 3 N 4 ceramics, the electrical conductivity , relative permittivity and dielectric loss were significantly improved by the in-situ introduced PyC from the pyrolysis of three-dimensional network DMAA-MBAM gel in green bodies and the SiC from the carbothermal reduction reaction between PyC and SiO 2 and Si 3 N 4 . The porous SiC–Si 3 N 4 composite ceramics prepared by the unoxidized Si 3 N 4 powders demonstrated the optimal EMW absorption properties with reflection loss of −22.35 dB at 8.37 GHz and 2 mm thickness, corresponding to the effective bandwidth of 8.20–9.29 GHz, displaying great application potential in EMW absorption fields.
研究领域:
材料科学
·
电子材料
✓ 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）