Synthesis of Fullerene by Spark Plasma Sintering and Thermomechanical Transformation of Fullerene Into Diamond on Fe-C C
- PDF / 3,631,789 Bytes
- 10 Pages / 432 x 648 pts Page_size
- 23 Downloads / 162 Views
Mater. Res. Soc. Symp. Proc. Vol. 1243 © 2010 Materials Research Society
Synthesis of Fullerene by Spark Plasma Sintering and Thermomechanical Transformation of Fullerene Into Diamond on Fe-C Composites Francisco C. Robles-Hernández1† and H. A. Calderon2‡ 1 2
University of Houston, Engineering Technology, Houston, TX, USA 77204 Departamento Ciencia de Materiales, ESFM-IPN, Mexico DF
ABSTRACT In this work, results are presented regarding the characterization of nanostructured Fe matrix composites reinforced with fullerene. The fullerene is a mix of 15 wt.%C60, 5 wt.%C70 and 80 wt.% soot that is the product of the primary synthesis of C60. The composite has been produced by means of mechanical alloying and sintered by Spark Plasma Sintering (SPS). The characterization methods include XRD, SEM and TEM. The C60 and C70 withstand mechanical alloying, SPS, and thermomechanical processing and act as a control agent during mechanical alloying. The results show that the mechanically alloyed and SPS product is a nanostructured composite. A larger amount of C60 is found in the sintered composite than in the original fullerene mix, which is attributed to an in-situ synthesis of C60 during the SPS process. The synthesis of C60 is presumably assisted by the catalytic nature of Fe and the electric field generated during the SPS process. In order to study the effect of high temperature, high strain, high heating and cooling rates on C60, the composite is subjected to a thermomechanical processing; demonstrating that some of the C60 resists the above described environment and some of it partially transforms into diamond. INTRODUCTION The synthesis of fullerene and carbon nanotubes has been successfully reported by different methods, the resulting structures include buckyballs, buckytubes, onions, giant fullerene structures, concentric structures, etc. [1-5]. The most common structures are the buckyballs (C60 and C70) formed by atomic arrangements of carbon in networks of pentagons, hexagons [2], and heptagons [6]. Fullerenes are usually synthesized and purified by the method proposed by Krätschmer [7]. As of today, the main focus has been given to characterization and applications; e.g. fullerenes have been used as reinforcements for structural materials [8-10]. Fullerenes are susceptible to transform by mechanical and heat treatment means [11-13] and can result in significant technological as well as scientific development. Previous research indicate that C60 and C70 can resist mechanical milling (in a ball mill) for up to 1000 h without amorphization; in contrast the milled C60 form polymer-like networks or molecules such as C120 [11]. Metallic and ceramic matrix composites can be successfully produced by mechanical alloying and mechanical milling, including ductile metals [8-10, 14-17]. The alloyed powders are usually highly homogeneous and nanostructured at low temperatures. Spark Plasma Sintering (SPS) is the ideal method to preserve the nanostructured nature of mechanically alloyed powders and allows an almost complete den
Data Loading...
