Advanced Powder Materials
·
2022
·
IF 0
Hailing Yang,Zhi Wang,Mengyong Sun,Fei Chen,Jun Ji,Sique Chen,Yingying Chen,Deli Ma,Zhenyu Zhang,Baocai Pan,Yulin Wei,Qinggang Li
As a non-toxic copolymer of isobutylene and maleic anhydride, Isobam is successfully used as a dispersant and a gelling agent for fabricating porous Si 3 N 4 ceramics by gel casting. The dispersity and rheological properties of the Si 3 N 4 slurry are influenced by the pH, milling time, and Isobam content which varies from 0.1 wt.% to 0.6 wt.%, and these factors are investigated. The slurry with 40 vol.% solid content and milled for 4 h has a high zeta potential at pH 12 (adjusted by Tetramethyl ammonium hydroxide (TMAH)), which means that the particles are well dispersed. The mechanisms of TMAH are electrostatic repulsion and steric hindrance. The viscosity of the slurry increases with the increase of Isobam content. After pressureless sintering at 1700 °C for 2 h, a uniform unique interlocking microstructure of rod-like β-Si 3 N 4 grains is observed, which may improve the flexural strength of the ceramics by intergranular fracture and particle pullout of β-Si 3 N 4 grains. The density and porosity of the samples fluctuate negligibly with the increase of Isobam content, and the Si 3 N 4 ceramic with 0.1 wt.% Isobam exhibits the highest bending strength of 251.6 MPa among all samples.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
Materials
·
2024
·Vol. 17
·期 14
·3410
·
IF 3.1
Yixuan He,Xiaohong Wang,Ning Ding,Hai Jiang,Wenzhong Lu
Isobam is widely used for fabricating ceramics through spontaneous gelation and has attracted considerable interest. However, the disadvantage of the Isobam system is the low gelation strength. The effects of suitable additives and the mechanism by which they effectively enhance the green body strength and the rheological behavior of an aluminum nitride (AlN) slurry with 50 vol% solid loading were investigated using polyethyleneimine (PEI), hydantoin epoxy resin, and trimethylolpropane triglycidyl ether (TMPGE). Results showed that the additives acted as both dispersants and cross-linkers in the AlN suspension using the Isobam gelling system. The flexural strength of the AlN green body increased by 42%, 204%, and 268% with the addition of 1 wt% PEI, 1 wt% hydantoin epoxy resin, and 0.5 wt% TMPGE, respectively. After sintering at 1700 °C, the AlN ceramic with 0.5 wt% TMPGE had flexural strength and thermal conductivity of 235 MPa and 166.44 W/(m·K), respectively, showing superior performance to the ceramics without additives.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Dongliang Mao,Shuang Yin,Xia Fang,Yang Wang,Qvan Li,Jian Yang
By surface modification with APTMS, spontaneous coagulation casting (SCC) of fused silica based on Isobam was achieved and the possible coagulation and molding mechanism is proposed. Through the interaction between the polar groups on the Isobam molecular chain and the incorporated –NH 2 groups on the surface of the silica particles, Isobam molecular chains were adsorbed on the surface of particles, which initiate the formation of flocs and the solidification of the suspension. The addition of dispersant TMAH results in the hydrolyzation of Isobam, forming more –COO – , which effectively improves the fluidity and stability of the suspension. Then the zeta potential , rheological properties and coagulation behavior of the suspension were systematically investigated and the fused silica suspension with high solid content (up to 52 vol%), low viscosity and good coagulation properties were prepared at 1.8 wt% TMAH and 0.5 wt% Isobam dosage. After sintering at 1260 °C for 4 hours, the fused silica ceramics (50 vol% solid content) shows a high bending strength of 61.59 MPa, the lowest dielectric loss tanδ of 8.46×10 -4 and the dielectric constant of 3.72. Thus, this work provides a simple and effective method for preparing fused silica and other ceramics with negative surface charge by Isobam SCC.
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
NANOTECHNOLOGY
·
2020
·Vol. 31
·期 13
·134003
·
IF 3.551
Yuantao Pei,Liqiong Wang,Liang Huang,Yuetong Hu,Quanli Jia,Haijun Zhang,Shaowei Zhang
ISOBAM-104-stabilized Ni2+ colloidal catalysts were synthesized through a facile method and used for hydrogen generation from hydrolysis of potassium borohydride (KBH4). Ni nanoparticles (NPs) were formed as the active phase during the catalytic process. Ultraviolet–visible spectrophotometry (UV–vis) and transmission electron microscopy were employed to characterize the structure and particle size of the as-formed Ni NPs. The results suggested that the catalytic activity of Ni2+ colloidal catalyst increased with the decreased size of as-formed Ni NPs, which is consistent with the results of density functional theory calculation. The highest catalytic activity of the catalyst can be 12400 ml-H2 min−1 g-Ni−1, which was even higher than that of noble Pt or Pd colloidal catalysts prepared using identical methods and catalytic conditions. According to the Arrhenius method, the ISOBAM-104-stabilized Ni2+ colloidal catalysts showed low activation energies of about 41.3 kJ mol−1 for the hydrogen generation from hydrolysis basic KBH4 solution.
研究领域:
化学
·
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yiwen Wu,Xinyi Pan,Bo Sun,Haiyan Li,Qing Yao
Due to the high-speed rotation and strong light exposure of digital light processing (DLP) projectors, the traditional polymer color wheel is at risk of deformation and color fading. Therefore, phosphor in glass (PiG) color filters will become a more heat-resistant alternative. In this work, we developed a single-step Isobam gel casting strategy that simultaneously forms green body with orange-red, green and transparent regions within a single mold, which avoided the need for subsequent stacking or gluing. In addition, the density of the green body was also increased by optimizing the solid content of the slurry. To suppress macroscopic defects that occur during molding, we first optimized the casting and demolding processes, obtaining green bodies with complete shapes and clear interfaces. Then the sintering system was optimized, and the following sintering system was finally determined. The temperature rises slowly from room temperature to 800 °C at a rate of 1 °C/min, and then cools along with the furnace chamber. During the cooling stage, residual stress is effectively released through slow temperature reduction, ensuring that the sample remains intact and free of cracks, and achieving defect control during forming stage.
研究领域:
材料科学
·
光学工程
·
无机非金属材料
·
先进制造
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2022
·Vol. 15
·期 13
·4667
·
IF 3.748
Hongmei Liu,Junjie Tian,Honghao Sun,Qian Xu,Jinyan Yu,Qing Yao
Phosphors-in-glass (PiGs) regarded as a promising phosphor-converter for white light emitting diodes (WLEDs) is being researched widely. However, there are few reports on the effect of changing the shape of PiGs on the color rendering index (CRI) and heat dissipation of WLEDs. In this paper, gel casting with Isobam was first attempted in preparing special-shaped PiGs successfully. It exhibited that 76 wt.% was the optimum solid content based on the rheological properties of slurry and the shrinkage of green bodies. The sintering rate should be kept at a low speed and glass transition temperature (Tg) of glass powders must be higher than sublimation temperatures (Ts) of APS and Isobam. The CRI of PiGs was increased by about 27% after changing the shape of PiGs from cylinder to dome. Most importantly, operating temperature also reduced effectively the increase of the surface area of PiGs. Therefore, changing the shape of PiGs by gel casting with Isobam is a creative way for high-power WLEDs lighting.Keywords:phosphors-in-glass;white light emitting diodes;gel casting;color rendering index;heat dissipation
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Junjie Tian,Hongmei Liu,Rong Guo,Honghao Sun,Yufeng Chen,Yi Wang,Qian Xu,Yao Zhu,Qing Yao
White light diodes (WLEDs) composed of blue chip and phosphor-converter are widely used in liquid crystal display (LCD) projectors as backlights. And it often needs a condenser lens to irradiate white light onto the LCD screen. In this paper, a large size lenticular shaped phosphors-in-glass (PiG) was prepared by Isobam-APS gel casting for the first time. The PiG could act for converting and condensing in LCD projector. Then a rectangular light spot similar to the shape of LCD screen was obtained to reduce the loss of light. The maximum temperatures of the chip and PiG were 62.1 °C and 57.3 °C respectively after working for 600 s and gradually stabilized by simulation. It was proved that simulation result was reliable through comparing with the actual measured value and the lenticular shaped PiG had good heat dissipation capacity for its large area. In conclusion, this is a successful application of PiG in LCD projector, which has guidance and promoting effect.
研究领域:
光学工程
·
材料科学
✓ 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）