Graphite Fibers and Filaments

This book was begun after three of the present authors gave a series of in­ vited talks on the subject of the structure and properties of carbon filaments. This was at a conference on the subject of optical obscuration, for which submicrometer diameter filaments with high length-to-diameter ratios have potential applications. The audience response to these talks illustrated the need of just one scientific community for a broader knowledge of the struc­ ture and properties of these interesting materials. Following the conference it was decided to expand the material presented in the conference proceedings. The aim was to include in a single volume a description of the physical properties of carbon fibers and filaments. The research papers on this topic are spread widely in the literature and are found in a broad assortment of physics, chemistry, materials science and engineering and polymer science journals and conference proceedings (some of which are obscure). Accordingly, our goal was to produce a book on the subject which would enable students and other researchers working in the field to gain an overview of the subject up to about 1987.

Contenu

1. Introductory Material on Graphite Fibers and Filaments.- 1.1 Introductory Discussion of Structure of Carbon Filaments.- 1.1.1 Ex-polymer Fibers.- 1.1.2 Arc-Grown Carbon Whiskers.- 1.1.3 CCVD Filaments.- 2. Synthesis of Graphite Fibers and Filaments.- 2.1 Carbon Fibers from Polymeric Precursors.- 2.1.1 Ex-rayon Fibers.- 2.1.2 Ex-PAN Fibers.- 2.1.3 Ex-pitch Fibers.- 2.2 Carbon Filaments by CCVD.- 2.2.1 General Considerations.- 2.2.2 Detailed Considerations.- 2.2.3 Growth Mechanisms.- 2.2.4 Growth Conditions.- 2.3 Carbon-Coated Filaments.- 2.4 Filaments Prepared from Carbon Arcs.- 2.5 Synthesis by Ion Bombardment.- 3. Structure.- 3.1 Graphite and Its Defect Structures.- 3.1.1 Structure of Ideal Graphite.- 3.1.2 Basic Scattering Concepts.- 3.1.3 Point Defects.- 3.1.4 Dislocations.- 3.1.5 Boundaries.- 3.1.6 Turbostratic Graphite.- 3.1.7 Partial Graphitization.- 3.2 Structure of Fibers and Filaments.- 3.2.1 Defects in Filaments with Partially Graphitic Structure.- 3.2.2 Highly Disordered Fibers and Filaments.- 3.3 Density.- 3.4 X-Ray Diffraction.- 3.4.1 Interlayer Spacing.- 3.4.2 X-Ray Studies of Turbostratic and Partially Graphitized Carbon.- 3.4.3 Preferred Orientation of the c-Axes.- 3.4.4 Crystalline Structures of Finite Size.- 3.5 Small Angle Scattering.- 3.6 Optical Microscopy.- 3.7 Electron Microscopy.- 3.7.1 SEM Characterization.- 3.7.2 High Resolution Transmission Electron Microscopy.- 3.7.3 Microstructure of the CCVD Filaments.- 3.7.4 EELS.- 3.8 Other Spectroscopies.- 3.9 Other Characterization Techniques.- 4. Lattice Properties.- 4.1 Elastic Parameters of Single Crystal Graphite.- 4.2 Lattice Dynamics of Single Crystal Graphite.- 4.2.1 Lattice Vibrations in the Long Wavelength Approximation.- 4.3 Models for the Elastic and Lattice Properties of Fibers.- 4.3.1 Effect of Defects on Elastic Parameters of Crystallites.- 4.3.2 Models for Young's and Torsional Moduli of Fibers.- 4.3.3 Rayleigh Waves in Thin Carbon Films.- 4.4 Raman Effect for Single Crystal Graphite.- 4.5 Raman Effect in Disordered Carbons.- 4.5.1 Raman Spectroscopy of Fibers.- 4.6 Photoconductivity in Graphite Fibers.- 5. Thermal Properties.- 5.1 Specific Heat.- 5.2 Thermal Expansion.- 5.3 Thermal Conductivity.- 6. Mechanical Properties.- 6.1 Elastic Parameters.- 6.1.1 Experimental Techniques.- 6.1.2 Experimental Observations.- 6.1.3 Internal Friction.- 6.1.4 Comparison of Elastic Moduli with Theory.- 6.2 Fracture, Stress and Strain.- 6.2.1 Experimental Observations.- 6.2.2 Models of Fracture Processes in Ex-polymer Fibers.- 6.3 Mechanical Properties of CCVD Fibers.- 7. Electronic Structure.- 7.1 Introduction and Overview.- 7.2 The Slonczewski-Weiss Model for Graphite.- 7.3 Electronic Structure in a Magnetic Field.- 7.3.1 Landau Levels in Three-Dimensional Graphite.- 7.3.2 Landau Levels in Two-Dimensional Graphite.- 8. Electronic and Magnetic Properties.- 8.1 Diamagnetism.- 8.1.1 Diamagnetism in Two-Dimensional Graphite.- 8.1.2 Magnetic Susceptibility of Carbon Fibers.- 8.2 Electron Spin Resonance.- 8.2.1 The g-Shift in Graphite.- 8.2.2 Anisotropy Effects.- 8.2.3 Application of ESR to Vapor-Grown Carbon Fibers.- 8.3 Electrical Resistivity.- 8.3.1 Experimental Techniques.- 8.3.2 Electrical Resistivity Data.- 8.3.3 Simple Two-Band Model.- 8.3.4 Size Effects in the Resistivity of Vapor-Grown Fibers.- 8.4 Magnetoresistance.- 8.4.1 Positive Magnetoresistance.- 8.4.2 Negative Magnetoresistance in Pregraphitic Carbons and Fibers.- 8.5 Hall Effect.- 8.6 Thermoelectric Power of Benzene-Derived Carbon Fibers.- 8.7 Piezoresistance and the Effect of Hydrostatic Pressure.- 8.7.1 Effect of Pressure on Resistance.- 8.7.2 Effect of Pressure on the Magnetoresistance.- 8.8 Non-ohmic Behavior.- 8.9 Electrical Noise.- 9. High Temperature Properties.- 9.1 High Temperature Thermal Properties.- 9.1.1 Thermal Conductivity.- 9.1.2 Thermal Expansion Coefficient.- 9.1.3 Specific Heats.- 9.2 High Temperature Resistivity.- 9.3 High Temperature Mechanical Properties.- 9.4 Oxidation Resistance.- 9.4.1 Experimental Results.- 9.4.2 Oxidation-Resistant Coatings.- 10. Intercalation of Graphite Fibers and Filaments.- 10.1 Structural Order and Intercalation.- 10.2 Structure and Staging.- 10.3 Lattice Properties.- 10.4 Electrical Transport Properties.- 10.4.1 Electrical Conductivity.- 10.4.2 Magnetoresistance.- 10.4.3 Weak Localization.- 10.5 Thermal Transport Properties.- 10.6 Thermopower.- 10.7 Mechanical Properties.- 10.8 Exfoliation.- 11. Ion Implantation of Graphite Fibers and Filaments.- 11.1 The Ion Implantation Process.- 11.2 Application to Carbon Fibers.- 11.3 Implantation-Induced Structural Modifications.- 11.3.1 Characterization of Samples.- 11.3.2 Regrowth.- 12. Applications of Graphite Fibers and Filaments.- 12.1 Economic Considerations.- 12.2 Structural Applications of Composites.- 12.2.1 Carbon Fiber-Polymer Composites.- 12.2.2 Carbon-Carbon Composites.- 12.3 Electrical Applications for Carbon Fibers.- 12.3.1 Electromagnetic Interference Shielding.- 12.3.2 Antistatic Coatings.- 12.3.3 Electrical Devices Based on Carbon-Resin Composites Near the Percolation Threshold.- 12.3.4 Fibers with Superconducting Coatings.- 12.3.5 CCVD Carbon on Ex-polymer Fibers.- 12.4 Thermal Applications.- 12.5 Nuclear Reactor Applications.- 12.6 Optical Applications.- 12.6.1 Application of Carbon Filaments as Obscurants.- 12.6.2 Low-Reflectivity Surfaces.- 12.7 Applications for Intercalated Carbon Fibers.- 12.8 Batteries and Other Electrochemical Applications.- 12.9 Medical Applications.- References.