Fabrication of SiCN MEMS by photopolymerization of pre-ceramic polymer

Liew, Li-Anne; Liu, Yiping; Luo, Ruiling; Cross, Tsali; An, Linan; Bright, Victor M.; Dunn, Martin L.; Daily, John W.; Raj, Rishi

doi:10.1016/s0924-4247(01)00723-3

Cited by 183 publications

(114 citation statements)

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“…[25] Nanophase composites of SiC/Si 3 N 4 have been synthesized by the carbothermal nitridation of silica, and the resulting composite powder has been used to make nonporous parts with excellent mechanical properties at temperatures as high as 1300 C. [26] Herein, we report the preparation of tailored, highly uniform SiCN and SiC porous structures, and validate their capability as catalyst support structures for high-temperature fuel reforming. We will show that these SiCN and SiC microstructured materials satisfy all three key requirements for the reforming of higher hydrocarbon fuels at the microscale: geometric surface areas per unit volume of the order of 10 5 to 10 8 m 2 per m 3 for pore diameters of 10 lm to 50 nm, porous features that are stable up to 1200 C, and pressure drops that are realistic in magnitude for microscale systems.…”

Section: Introductionmentioning

confidence: 95%

Tailored Macroporous SiCN and SiC Structures for High-Temperature Fuel Reforming

Sung¹,

Mestres²,

Mitchell³

et al. 2005

Adv. Funct. Mater.

134

110

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The catalytic reforming of hydrocarbons in a microreformer is an attractive approach to supply hydrogen to fuel cells while avoiding storage and safety issues. High‐surface‐area catalyst supports must be stable above 800 °C to avoid catalyst coking; however, many porous materials lose their high surface areas below 800 °C. This paper describes an approach to fabricate macroporous silicon carbonitride (SiCN) and silicon carbide (SiC) monoliths with geometric surface areas of 105 to 108 m2 per m3 that are stable up to 1200 °C. These structures are fabricated by capillary filling of packed beds of polystyrene or silica spheres with low‐viscosity preceramic polymers. Subsequent curing, pyrolysis, and removal of the spheres yielded SiCN and SiC inverted beaded monoliths with a chemical composition and pore morphology that are stable in air at 1200 °C. Thus, these structures are promising as catalyst supports for high‐temperature fuel reforming.

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Section: Introductionmentioning

confidence: 95%

Tailored Macroporous SiCN and SiC Structures for High-Temperature Fuel Reforming

Sung¹,

Mestres²,

Mitchell³

et al. 2005

Adv. Funct. Mater.

134

110

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show abstract

“…R. Raj's group reported the very meaningful achievement by preparing SiCN ceramic MEMS devices using polyureamethylvinylsilazane as a precursor. [47][48][49] Even primitive types of high-temperature MEMS, i.e., electrostatic actuators, a pressure transducers, and combustion chambers were developed mainly using preceramic polymers that forms SiCN ceramics by pyrolysis via a temperature or radiation induced transformation of a processable liquid state to an infusible solid state cured polymer. This suggests that multi-layered ceramic MEMS can be fabricated by adding and curing successive layers of liquid polymers on top of each other using multilevel photopolymerization.…”

Section: -45mentioning

confidence: 99%

Fabrication of SiC-Based Ceramic Microstructures from Preceramic Polymers with Sacrificial Templates and Lithographic Techniques-A Review

Yoon

Lee

Kim

2006

J. Ceram. Soc. Japan

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Review péÉÅá~ä fëëìÉ Äó dìÉëí bÇáíçêëW lêÖ~åáÅ-íç-fåçêÖ~åáÅ`çåîÉêëáçå mêçÅÉëë Ñçê mçäóãÉê-aÉêáîÉÇ`Éê~ãáÅë c~ÄêáÅ~íáçå çÑ pá`_~ëÉÇ`Éê~ãáÅ jáÅêçëíêìÅíìêÉë Ñêçã mêÉÅÉê~ãáÅ mçäóãÉêë ïáíÜ p~ÅêáÑáÅá~ä qÉãéä~íÉë~åÇ iáíÜçÖê~éÜáÅ qÉÅÜåáèìÉë-^oÉîáÉï Processes for fabricating ceramic microstructures are in demand for use in areas such as microreactors and MEMS that can be used in harsh environments requiring a high temperatures tolerance, corrosion resistance, as well as tribological properties. This review describes the manufacture of tailored porous SiC ceramic microstructures using sacrificial templates, the feasible applications of microporous structures and microchannels as a microreactor, and microfabrication of preceramic polymers using soft lithography and sterolithography. Macroporous and mesoporous SiC ceramic structures have been fabricated using various templates including packed silica sphere assemblies, porous carbon templates, and nanoporous silica structures. In addition, SiC nanotubes have also been obtained from an alumina membrane used as a template. These porous structures were generally obtained using a series of infiltration, curing and pyrolysis, and chemical or oxidative etching steps. Complicated SiC ceramic microfeatures were fabricated using near-net shape lithographic techniques to preceramic polymers. Line patterns and porous channels were produced by soft lithography, whereas the 3D woodpile structures were fabricated using stereolithography. These novel structures show great promises for use in high temperature micro-reactors for the on-demand reforming of higher hydrocarbons into hydrogen in portable power sources. It is expected that the integration of preceramic polymers into new economic manufacturing strategies such as precursor casting in templates and lithography utilization will be a break-through technology for the creation of complex ceramic nanostructures.

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“…[1][2][3][4][5][6][7][8] However, the general properties of polymers are not suffi cient for some applications, and 3D ceramic micropatterned structures are continuously in-demand for advanced devices working at high temperature or in harsh, corrosive environments and applications requiring tribological, mechanical, and chemical resistance. [9][10][11][12][13][14] Selective laser sintering (SLS) [ 15,16 ] and 3D printing (3DP) are well known additive manufacturing processes for ceramic powders, [17][18][19] while stereolithography (SL), laser-based or fusion technologies have been employed to manufacture ceramic components starting from ceramic slurries. [20][21][22] Other 3D ceramic fabrication processes employ sheets of material, such as laminated object manufacturing (LOM) and computeraided manufacturing of laminated engineering materials (CAM-LEM).…”

mentioning

confidence: 99%