Surface coating on carbon nanofibers with alumina precursor by different synthesis routes

Abstract

ElsevierBorrell Tomás, MA.; Rocha, VG.; Torrecillas, R.; Fernandez, A. (2011) ABSTRACTAlumina-reinforced carbon nanofiber nanocomposites were prepared using different routes; powders mixture, colloidal route and sol-gel process followed by spark plasma sintering (SPS). CNFs/xAl2O3 (x=10-50 vol.%) were prepared through nanopowders mixing in a high-energy attrition milling. The main limitations in the preparation of this kind of nanocomposites are related to the difficulty in obtaining materials with a homogeneous distribution of both phases and the different chemical nature of CNFs and Al2O3, which causes poor interaction between them. A surface coating of CNFs by wet chemical routes with an alumina precursor is proposed as a very effective way to improve the interaction between CNFs and Al2O3. An improvement of 50% in fracture strength was found for similar nanocomposite compositions when the surface coating 2 was used. The improved mechanical properties of these nanocomposites are caused by stronger interaction between the CNFs and Al2O3.

Enhanced physical properties of γ-Al2O3–rGO hybrids prepared by solvothermal and hot-press processing

“…12 Alumina has applications in the eld of dental implants, high speed cutting tools, chemical insulators, electrical insulators, and wear resistance coatings. 13,14 To improve its mechanical properties, carbon nanotubes have been used to enhance the fracture toughness (by 94%), hardness (by 13%) and exural strength (by 6.4%) of alumina. 15 Ballmilled alumina/zirconia/graphene composites have been investigated with 40% enhancement in fracture toughness on addition of graphene platelets.…”

Improvement of CNFs/SiC nanocomposite properties obtained from different routes and consolidated by pulsed electric-current pressure sintering

“…Nevertheless, nanocomposites show significantly higher relative densities when CNFs content is increased. This trend is completely opposite to the behavior of Al 2 O 3 /CNFs and ZrO 2 /CNFs composites [34,35], suggesting that carbon nanofibers act as a sintering additive having a noticeable effect on the densification behavior of SiC ceramics.…”

“…Alumina surface coating on CNFs has been achieved by the procedure published elsewhere [34]. Briefly, in this process a three dimensional network which perfectly interconnects the sol particles in the whole volume is formed.…”

“…Surface coating of CNFs has been carried out employing sol-gel processing route with an alumina precursor, as it has been described in a previous work (see [34] for details). AlCl 3 Á 6H 2 O ( 499% purity, Fluka) was used as an alumina precursor.…”

“…AlCl 3 Á 6H 2 O ( 499% purity, Fluka) was used as an alumina precursor. The modified powders have been characterized in terms of thermogravimetric behavior and XRD analysis as shown in [34]. The final content of Al 2 O 3 on the CNFs surface was 10 vol%.…”