Applicability of nitride powders as foaming agents in superplastically foamed ceramics

Yokota, Hiroshi; Hayashi, Hidetaka; Kishimoto, Akira

doi:10.2109/jcersj2.117.1233

Cited by 10 publications

(8 citation statements)

References 16 publications

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“…While the process does not yield with highly porous samples (ϕ T was generally below 40%), yttria-stabilized zirconia (3YSZ and 8YSZ), alumina (with superplasticity-facilitating dispersoids; 3YSZ, 0YZ or spinel) and titania-based closed porosity ceramics were produced. [72][73][74][75][76][77][78][79][80] Similarly, recycled materials (eg, granite scrap and fired clay tailings) were used with SiC to cause gas generation and form closed porosity ceramic foams. 81 In a different technique, closed porosity aluminum oxynitride (AlON) (ϕ C = 80%) foams were made by combustion synthesis in between 2165°C and 2650°C for a very short time (10 seconds).…”

Section: Chemical Blowing Agentsmentioning

confidence: 99%

“…In this simple method, few percent (generally below 10 wt%) of foaming agent was coated or mixed with the target composition, pressed and sintered for extended periods (eg, 8 hours) at elevated temperatures. While the process does not yield with highly porous samples (ϕ T was generally below 40%), yttria‐stabilized zirconia (3YSZ and 8YSZ), alumina (with superplasticity‐facilitating dispersoids; 3YSZ, 0YZ or spinel) and titania‐based closed porosity ceramics were produced . Similarly, recycled materials (eg, granite scrap and fired clay tailings) were used with SiC to cause gas generation and form closed porosity ceramic foams .…”

Section: Processing Strategiesmentioning

confidence: 99%

“…Kishimoto and his colleagues [72][73][74][75][76][77][78][79][80] followed solid-state (or superplastic) foaming by using various high temperature CBAs (SiC, Si 3 N 3 , AlN, etc). The reduction and/or active oxidation of these additives (see reactions 1-3 for SiC) during prolonged sintering of the superplastic matrix causes foaming.…”

Section: Chemical Blowing Agentsmentioning

confidence: 99%

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Closed porosity ceramics and glasses

2020

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In the last three decades, considerable effort has been devoted to obtain both open and closed porosity ceramics & glasses in order to benefit from unique combination of properties such as mechanical strength, thermal and chemical stability at low‐relative density. Most of these investigations were directed to the production and the analysis of the properties for open porosity materials, and regrettably quite a few compositions and manufacturing methods were documented for closed porosity ceramics & glasses in the scientific literature so far. This review focuses on the processing strategies, the properties and the applications of closed porosity ceramics & glasses with total porosity higher than 25%. The ones below such level are intentionally left out and the paper is set out to demonstrate the porous components with deliberately generated closed pores/cells. The processing strategies are categorized into five different groups, namely sacrificial templating, high‐temperature bonding of hollow structures, casting, direct foaming, and emulsions. The principles underlying these methods are given, with particular emphasis on the critical issues that affect the pore characteristics, mechanical, thermal and electrical properties of the produced components.

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Section: Chemical Blowing Agentsmentioning

confidence: 99%

Section: Processing Strategiesmentioning

confidence: 99%

Section: Chemical Blowing Agentsmentioning

confidence: 99%

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Closed porosity ceramics and glasses

2020

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“…13) Ceramic monofoams were fabricated successfully using AlN and Si 3 N 4 as foaming agents. In contrast, when BN was used as a foaming agent, we could not fabricate well developed ceramic foams due to cracks and fractures.…”

Section: Ceramic Foams From a Diverse Matrix And Foaming Agentsmentioning

confidence: 99%

Superplastically foaming method for inclusion of closed pores in fully densified ceramics

Kishimoto

2013

J. Ceram. Soc. Japan

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Porous ceramics incorporate pores to improve material properties, including thermal insulation, while maintaining inherent ceramic properties such as corrosion resistance and high mechanical strength. Conventional porous ceramics are usually fabricated by insufficient sintering that excludes pores; thus, it must be terminated in an early stage to maintain high porosity. The premature termination leads to degraded strength and durability. We developed a superplastic-foaming method to fabricate ceramic foams in the solid state. In this method, the inserted foam agent evaporates after full densification of the matrix at the sintering temperature. Closed pores expand by superplastic deformation driven by the gas pressure. The pores are introduced after sintering the solid polycrystal. Then, only closed pores are introduced, improving the insulation of gas, sound and heat. The pore walls are fully densified for high mechanical strength. Compared to the melt-foaming method, this technique is practical because the fabrication temperature is far below the material's melting point, and it does not require moulds. In addition, the size and location of the pores can be controlled by the amount and position of the foam agent.

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“…To overcome this drawback, we have already proposed a superplastically foaming method [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] . In this method, foaming agents instead of pore formers are incorporated into ceramics matrix powder to make a green compact.…”

mentioning

confidence: 99%

Utilizing Rice Husk for Ceramic and Glass Foams as Matrix and Foaming Agent

Matsuoka

Teranishi

Hayashi

et al. 2018

J. Jpn. Soc. Powder Powder Metallurgy

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Rice husk was converted to SiC or SiO 2 and used for making porous ceramics or foamed glass. The rice husk derived SiC was aggregated, but by adding a peptizer it was possible to disperse to the same extent as commercially available SiC. Such dispersed SiC derived from rice husk was able to be used as a foaming agent to fabricate ceramic foams. We also succeeded in making foamed glass using rice husk derived SiC as a foaming agent and in fabricating foamed glass using rice husk derived silica matrix added with glass modifiers.

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Applicability of nitride powders as foaming agents in superplastically foamed ceramics

Cited by 10 publications

References 16 publications

Closed porosity ceramics and glasses

Closed porosity ceramics and glasses

Superplastically foaming method for inclusion of closed pores in fully densified ceramics

Utilizing Rice Husk for Ceramic and Glass Foams as Matrix and Foaming Agent

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