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Metal Composites (metal + composite)

Distribution by Scientific Domains
Polymers and Materials Science40%

Selected Abstracts

Preparation and self-assembly of polyaniline nanorods and their application as electroactive actuators

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010
Seong Hun Kim
Abstract To improve the performance of ion-exchange polymer,metal composite (IPMC) actuators, an electrical pathway material for enhancing the surface adhesion between the membrane and the metal electrodes of the IPMC was studied. As an efficient electrical pathway material, polyaniline nanorods (PANI-NRs) doped with p -toluene sulfonic acid (TSA) were synthesized with a template-free method. The factors affecting polyaniline morphology were studied with various dopant concentrations and oxidant feeding rates. Highly conductive PANI-NRs were formed when they were synthesized with ammonium persulfate at a 5.0 mL/min oxidant feeding rate and doped with 0.125M TSA. The conductivity of the PANI-NRs was 1.15 × 10,1 S/cm, and their diameters and lengths were 120,180 nm and 0.6,2 ,m, respectively. To apply the membrane as an actuator, perfluorosulfonated ionomer (Nafion)/PANI-NR blends were prepared by solution blending and casting. The actuating ability of the three-layered membrane consisting of Nafion/PANI-NR blends was then examined and compared with that of Nafion only. The actuating ability of the IPMC was improved when Nafion/PANI-NRs were used as electrical pathways. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

DES Design: Theoretical Advantages and Disadvantages of Stent Strut Materials, Design, Thickness, and Surface Characteristics

JOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2009
F.A.C.C., F.A.H.A., F.S.C.A.I., STEVEN R. BAILEY M.D.
Endovascular stents have historically been manufactured using metals and metal composites. While metallic implants in nonvascular locations have been biologically well tolerated, endovascular implants have been plagued by neointimal proliferation resulting in recurrent stenosis. Using prior in vitro and in vivo outcomes, novel research projects are under way to improve vascular implants. This review summarizes prior investigations of metal stents, analyzes new biopolymeric systems, and examines emerging technologies and manufacturing processes for surface modifications as well as bioabsorbable stent materials. Limitations of these new materials and manufacturing processes will be discussed along with potential new biologic applications. [source]

Hot Isostatic Pressing of Cubic Boron Nitride,Tungsten Carbide/Cobalt (cBN,WC/Co) Composites: Effect of cBN Particle Size and Some Processing Parameters on their Microstructure and Properties

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2007
V. Martínez
Cubic boron nitride (cBN)-cemented carbide composites have gained attraction over the last few years because of their potential uses as wear parts. The densification behavior of cBN,hard metal composites by glass encapsulation hot isostatic pressing,has been investigated. Composites with different cBN grades (from 0/0.5 to 6/12 ,m particle sizes) and cBN content (up to 50 vol%) were selected for this study. Near-full densification was obtained at temperatures between 1100° and 1200°C, and pressures between 150 and 200 MPa, respectively, while no phase transformation of cBN into the low-hardness hexagonal form has been detected by X-ray diffraction. The addition of cBN to the hard metal base material led to an increase of hardness, a significant increase of fracture toughness (KIC measured by Vickers indentation), and a moderate decrease of mechanical strength (determined by three-point bending). [source]

Thermal expansion co-efficient of nanotube,metal composites

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11-12 2009
Sheikh M. Uddin
Abstract Thermal expansion exhibits considerable challenges developing residual stresses at the interfaces of different materials treated at high temperature. Electrical devices containing materials with different thermal expansion behaviour very often suffer this problem. Thermal expansion co-efficient (TEC) of different metals can be tuned by using carbon nanotube (CNT). Metal matrix composites (MMCs) using CNT are fabricated by hot-press sintering method and TEC of the composites are investigated throughout a wide range of temperature (,155 to 275,°C). Reduction of TEC of the composite materials was observed up to 20% compared to that of pure metals. The effect of CNTs in the matrix materials and the mechanism behind the improvement are explained from the microscopic investigation of the composites. [source]

Fabrication of Cobalt and Cobalt Oxide/Graphene Composites: Towards High-Performance Anode Materials for Lithium Ion Batteries

CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 2 2010
Shubin Yang Dr.
Pave a way to high-performance anode materials: Organic metal/graphene composites are fabricated through an in,situ assembly of disc-shaped phthalocyanine molecules with graphene sheets during the chemical reduction of graphite oxide, which enables a homogenous dispersion of Co and Co3O4 nanoparticles in the sheets after simple pyrolysis and oxidation. The resulting Co3O4/graphene composites exhibit remarkable lithium storage performance. [source]