FABRICATION OF ALUMINA/ZIRCONIA (YSZ) NANOCOMPOSITES BY GELCASTING PROCESS

Gelcasting process as a promising method for fabrication of reliable ceramics has been utilized to develop alumina-zirconia nanocomposites from nanosized powders. Sedimentation and viscosity measurement were performed to find the accurate dispersing condition for production of alumina-zirconia nanocomposite slurry with high solid loading and low viscosity. The gelcasting was accomplished by in situ polymerization of an acrylamide base monomer. The effects of solid loading, viscosity and deairing were also studied. Finally, crack and flaw free samples with relative densities of 99%, were achieved from the optimal slurry with 35vol. % solid loading, by performing sintering at 1600°C for 2 hours. SEM micrographs showed dense microstructure with fine and homogenous dispersion of zirconia phase in the alumina matrix.

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Gelcasting of BaO-Nd2O3-TiO2 Microwave Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.280-283.747 ◽

2007 ◽

Vol 280-283 ◽

pp. 747-750

Author(s):

C. Fang ◽

Yan Xiang Wang ◽

Z.G. Su ◽

Zhao Xian Xiong

Keyword(s):

Solid Loading ◽

Green Body ◽

Microwave Ceramics ◽

Forming Process ◽

High Solid Loading ◽

Low Viscosity ◽

Microwave Ceramic ◽

Ceramic Components ◽

Gelcasting Process

Gelcasting is a novel ceramic forming process for fabricating products of complex-shaped ceramics. In this contribution, the gelcasting process is applied to manufacture green body of microwave ceramic components for resonators, oscillators and antennas. Calcined powders, dispersant and organic monomers are mixed together by ball-milling to acquire high solid loading slurry with low viscosity. After addition of initiator and catalyst, the slurry is cast into a non-pours mold and then polymerized. The slurry is thus solidified in situ and the green bodies with the desired shapes are obtained. The dried body is rather strong and can be machined so as to get more precise or complex-shaped components. Then the green bodies are sintered at high temperature. The microwave properties (εr, Q, τf) and microstructures of the ceramics prepared by gelcasting are compared with those of die-pressed ones.

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Preparation of high solid loading and low viscosity ceramic slurries for photopolymerization-based 3D printing

Ceramics International ◽

10.1016/j.ceramint.2019.03.024 ◽

2019 ◽

Vol 45 (9) ◽

pp. 11549-11557 ◽

Cited By ~ 27

Author(s):

Zhangwei Chen ◽

Junjie Li ◽

Chengbo Liu ◽

Yu Liu ◽

Junyi Zhu ◽

...

Keyword(s):

3D Printing ◽

Solid Loading ◽

High Solid ◽

High Solid Loading ◽

Low Viscosity

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Improving the Porosity Features Control of Ceramic Cellular Components through a Modified Gelcasting Process

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.62.147 ◽

2010 ◽

Vol 62 ◽

pp. 147-156

Author(s):

Mariangela Lombardi ◽

Sylvain Meille ◽

Jérôme Chevalier ◽

Laura Montanaro

Keyword(s):

In Situ Polymerization ◽

Total Pore Volume ◽

Ceramic Materials ◽

Gelling Agent ◽

Pore Former ◽

Volume Percentage ◽

Controlled Porosity ◽

Gelcasting Process ◽

Cellular Components

An innovative gelcasting procedure was successfully developed to produce cellular ceramic materials, having controlled porosity features, tailored for a specific application. This process combines a conventional gelcasting based on in situ polymerization of a natural gelling agent to a sacrificial template method, in which polyethylene (PE) spheres having a controlled size distribution are used as pore former. By a suitable selection of the PE spheres fraction and volume percentage, it is possible to modify some important porosity characteristics of the final component, such as the mean pore size, the total pore volume, the pore geometry as well as the pore interconnection number and size. The effectiveness and versatility of this procedure was demonstrated by exploiting it in the preparation of porous components made of several ceramic powders (alumina, zirconia, hydroxyapatite) different in terms of composition and size.

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Aluminum nitride shaping by non-aqueous gelcasting of low-viscosity and high solid-loading slurry

Ceramics International ◽

10.1016/j.ceramint.2015.12.036 ◽

2016 ◽

Vol 42 (4) ◽

pp. 5569-5574 ◽

Cited By ~ 18

Author(s):

Liya Shen ◽

Xueshun Xu ◽

Wei Lu ◽

Bo Shi

Keyword(s):

Aluminum Nitride ◽

Solid Loading ◽

High Solid ◽

High Solid Loading ◽

Low Viscosity

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Self-assembling Peptide Scaffolds Promote Enamel Remineralization

Journal of Dental Research ◽

10.1177/154405910708600507 ◽

2007 ◽

Vol 86 (5) ◽

pp. 426-430 ◽

Cited By ~ 177

Author(s):

J. Kirkham ◽

A. Firth ◽

D. Vernals ◽

N. Boden ◽

C. Robinson ◽

...

Keyword(s):

Tissue Engineering ◽

De Novo ◽

In Situ Polymerization ◽

Three Dimensional ◽

Dental Enamel ◽

Dental Tissue ◽

Skeletal Tissue ◽

Low Viscosity ◽

Self Assembling

Rationally designed β-sheet-forming peptides that spontaneously form three-dimensional fibrillar scaffolds in response to specific environmental triggers may potentially be used in skeletal tissue engineering, including the treatment/prevention of dental caries, via bioactive surface groups. We hypothesized that infiltration of caries lesions with monomeric low-viscosity peptide solutions would be followed by in situ polymerization triggered by conditions of pH and ionic strength, providing a biomimetic scaffold capable of hydroxyapatite nucleation, promoting repair. Our aim was to determine the effect of an anionic peptide applied to caries-like lesions in human dental enamel under simulated intra-oral conditions of pH cycling. Peptide treatment significantly increased net mineral gain by the lesions, due to both increased remineralization and inhibition of demineralization over a five-day period. The assembled peptide was also capable of inducing hydroxyapatite nucleation de novo. The results suggest that self-assembling peptides may be useful in the modulation of mineral behavior during in situ dental tissue engineering.

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Microfabrication of High-Aspect Ratio KNN Lead-Free Piezoceramic Pillar Arrays by Aqueous Gelcasting

Ceramics ◽

10.3390/ceramics3030026 ◽

2020 ◽

Vol 3 (3) ◽

pp. 287-296

Author(s):

Cailing Wu ◽

Benke Li ◽

Xiaofeng Wang ◽

Feng Ji ◽

Dou Zhang ◽

...

Keyword(s):

Aspect Ratio ◽

High Aspect Ratio ◽

Lead Free ◽

Solid Loading ◽

High Mechanical Strength ◽

Pillar Array ◽

Novel Approach ◽

Pillar Arrays ◽

Gelcasting Process

The present paper reported a novel approach for the fabrication of a high-aspect ratio (K, Na)NbO3 (KNN) piezoelectric micropillar array via epoxy gelcasting, which involves the in situ consolidation of aqueous KNN suspensions with added hydantoin epoxy resin on a polydimethylsiloxane (PDMS) soft micromold. KNN suspensions with solid loadings of up to 45.0 vol.% have rheological behavior, which was suitable for the gelcasting process. The uniform green KNN bodies derived from the optimized suspension of 42.0 vol.% solid loading and 15.0 wt.% resin had exceptionally high mechanical strength (9.14 MPa), which was responsible for the integrity of the piezoceramic micropattern structure. The square-shaped KNN piezoelectric pillar array with lateral dimensions of up to 5 μm and an aspect ratio of up to five was successfully fabricated.

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Gel Casting of Large-Sized, Complex-Shaped RBSC Component

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.512-515.395 ◽

2012 ◽

Vol 512-515 ◽

pp. 395-398 ◽

Cited By ~ 1

Author(s):

Hai Lin Liu ◽

Yan Li Huo ◽

Chun Peng Wang ◽

Jie Tang ◽

Yu Feng Chen

Keyword(s):

Rheological Property ◽

Process Parameters ◽

Casting Process ◽

Sintered Body ◽

Solid Loading ◽

Green Body ◽

High Solid ◽

High Solid Loading ◽

Low Viscosity ◽

Gel Casting

In this paper, gel casting process of RBSC was deeply studied. The rheological property of C/SiC slurry was analyzed, high solid loading (67%) slurry with low viscosity was produced. Also the properties of green body and sintered body were studied. Finally, through optimizations of process parameters, a large-sized (650mm), complex-shaped (with thin ribs about 2.5mm) was fabricated through gel casting process with no cracks and deformation. It was showed that gel casting process is suitable for producing large-sized, complex-shaped RBSC components.

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Digital Light Processing 3D Printing of Surface-oxidized Si3N4 Coated by Silane Coupling Agent

10.21203/rs.3.rs-786411/v1 ◽

2021 ◽

Author(s):

Ping Yang ◽

Zhenfei Sun ◽

Shengwu Huang ◽

Jun Ou ◽

Shanghua Wu

Keyword(s):

3D Printing ◽

Coupling Agent ◽

Light Absorption ◽

Silane Coupling Agent ◽

Solid Loading ◽

Digital Light Processing ◽

High Solid ◽

High Solid Loading ◽

Low Viscosity ◽

Silane Coupling

Abstract Due to high light absorption and high refractive index of silicon nitride (Si3N4) ceramic, it is difficult to prepare Si3N4 slurry with favourable curing ability, high solid loading and low viscosity at the same time, and thus the high quality Si3N4 parts are hard to fabricate via Digital Light Processing (DLP). In this paper, oxidation process was used to enhance the curing behavior of Si3N4 slurry, and then silane coupling agent (KH560) was used to improve the rheological properties of the oxidized Si3N4 slurry. The effect of Si3N4 slurry with oxidation and modification on its rheological behavior, light absorption, curing ability and stability have been systematically investigated. A Si3N4 slurry with abundant photocuring ability, high solid loading, low viscosity and reliable stability was fabricated by the oxidized (1h) and KH560 (1wt.%) modified Si3N4 powders, and the dense Si3N4 ceramic parts were produced by this slurry via DLP 3D printing. Subsequently, the influence of oxidation and modification on microstructure, mechanical properties and thermal conductivity have been investigated. Finally, the performances of the DLP 3D printed samples are close to the isostatic cool pressing (ICP) fabricated samples. Consequently, DLP has well potential to fabricate high-performance Si3N4 ceramics.

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