Accession Number:

ADA592382

Title:

Bio-Inspired Ceramic/Carbon Composites

Descriptive Note:

Corporate Author:

OXFORD UNIV (UNITED KINGDOM)

Personal Author(s):

Report Date:

2013-05-01

Pagination or Media Count:

11.0

Abstract:

The influence of different parameters including catalyst concentration, infiltration time, and carbon sources on the quality and homogeneity of the in situ grown carbon nanotubes CNTs was evaluated. The synthesis approach we used was based on in situ aerosol assisted chemical vapour deposition using alumina scaffolds supplied by Imperial as substrate materials. Fe2O3 nanoparticles with sizes between 5-7nm were freshly prepared, dispersed in cyclohexane and, used as metal catalysts. The infiltration of the scaffolds with catalyst particles was conducted for different times and concentrations. The as-infiltrated scaffold placed in a quartz tube inside a furnace and heated to 800 C at a rate of 10 Cmin in an Ar flow of 1000 sccm. Once the furnace reached 800 C and the temperature was stable the substrate was kept for a further 10-15 min, then the gases were switched to Ar 200 sccm, H2 150 sccm, and 50 sccm acetylene C2H2 which was used as carbon source. Following the synthesis, the sample was cooled down at a rate of ca. 2.5 Cmin under Ar 1000 sccm, more details about the infiltration process and the synthesis are in the previous report. Fe2O3 nanoparticles with concentrations ranging from 0.2 to 0.02 M were used. As a first approach, the infiltration time was 7 days for all the samples. For 0.2, 0.1 and 0.06M concentrations the results were very similar. The outside of the scaffold directly in contact with the catalyst solution appeared completely covered with CNTs while the inside walls showed less CNT coverage with a high trend to agglomerate at the grain boundaries. Figure 1 shows the scanning electron micrograph SEM images of the as-synthesized hybrid scaffoldCNTs for 0.1M Fe2O3 nanoparticles concentration.

Subject Categories:

  • Physical Chemistry
  • Refractory Fibers

Distribution Statement:

APPROVED FOR PUBLIC RELEASE