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Low-cost Process (low-cost + process)

Distribution by Scientific Domains

Polymers and Materials Science	60%

Selected Abstracts

Controlled Etching of Carbon Nanotubes by Iron-Catalyzed Steam Gasification,

ADVANCED MATERIALS, Issue 21 2007
W. Xia
A localized etching method based on catalytic steam gasification was developed to modify carbon nanotubes in a pre-determined manner. The etching, occurring only at the interface, created different etching patterns depending on the iron catalyst by means of an eco-friendly, low-cost process using water vapor. Both the surface roughness and the number of surface defects such as edge planes were significantly enhanced. [source]

Forming Highly Ordered Arrays of Functionalized Polymer Nanowires by Dewetting on Micropillars,

ADVANCED MATERIALS, Issue 9 2007
J. Guan
1D nanostructures are of great interest for numerous applications: a simple and low-cost process to generate large arrays of polymer nanowires by dewetting aqueous polymer solution on an array of micropillars is developed. These nanowires are typically less than 10,nm in lateral size and can be functionalized by incorporation of molecules or nanoparticles such as quantum dots (see figure). [source]

A Process for Cf/SiC Composites Using Liquid Polymer Infiltration

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2001
Zbigniew S. Rak
A continuous carbon fiber/silicon carbide matrix composite material has been produced by a low-cost process. In this process the space in a two-dimensional carbon fiber preform is filled with a SiC powder by a pressure infiltration method. High particle packing densities are achieved within the fiber preform in this way. The compact body is heat-treated at 400°C to form a porous framework, which is then infiltrated with a liquid preceramic polymer, CerasetTM SN. Subsequently the infiltrated polymer is pyrolyzed in argon at 1300°C. The microstructure of the final composite is characterized, and mechanical properties of these composites are discussed. [source]

Photonic circuits writing with UV pulsed laser

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2007
K. R. Kribich
Abstract Photonics technology is employed in a growing number of applications. Biological and chemical sensors (E. Udd, Fiber Optic Sensors: An Introduction for Engineers and Scientists, Wiley, New York, 1991 [1]) for health and environment demand an adaptable technology. Network development towards the end-user requires more interconnecting components. Vision, lighting, data processing in hostile environment (spatial, military) need specific technologies. A flexible and low-cost process using good quality material is necessary. The sol-gel process is a chemical method to fabricate glasses at ambient pressure and moderate temperature. Hybrid materials (H.K. Schmidt et al., Proc. SPIE 3136, 220 (1997) [2]), mixing organic and inorganic parts, offer the advantages of polymer-like materials and glasses. We report on a new hybrid sol-gel technology to overcome the drawbacks of the formerly presented one (H. Krug, F. Teillantes, P.W. Oliviers, and H. Schmidt, Proc. SPIE 1758, 448 (1992) [3]). We present the material synthesis, an accurate and flexible fabrication process based on a pulsed UV laser lithography system and the characterisation of the optical waveguides and photonic circuits realised. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Synthesis of ultrafine titanium carbonitride powders,

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 5 2001
Frederic Monteverde
Abstract Titanium-carbonitride-based materials are very hard materials with increasing technical importance. They are mainly used in composites with various metal carbides and/or metallic binders (cermets) for metal cutting operations. These applications call for the synthesis of titanium carbonitride powders with homogeneous chemical composition, as small as possible grain size and narrower grain size distribution. Nowadays on the market, only commercial submicrometric (0.5,2,,m) powders are available. Starting from blends of nanosize commercial TiN or TiO2 powders mixed with different carbon powders (carbon black, active carbon), this study aimed to set up a low-cost process to synthesize fine and pure TiC1,X,NX powders with an X value close to 0.5. The morphology of the as-obtained powders and the progress of the reaction were investigated by scanning electron microscopy and X-ray diffraction. The stoichiometric parameter X was estimated on the basis of a TiC1,X,NX Raoultian solid solution together with Vegard's rule. The results are presented and discussed to assess relations between powder characteristics and processing conditions. The most encouraging results were obtained using a mixture TiN,+,10,wt%C (carbon black) processed at 1430,°C for 3,h under flowing argon. Regularly shaped particles with limited agglomeration ranged from 100 to 300,nm and an X value close to 0.5 Copyright © 2001 John Wiley & Sons, Ltd. [source]