Stability of carbon-carbon composites intercalated with copper (II) chloride
Beata Macherzyńska Akademia Górniczo-Hutnicza, Wydział Inżynierii Materiałowej i Ceramiki, ul. Reymonta 23, 30-059 Kraków
Annals 2 No. 5, 2002 pages 390-393
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abstract In this work, the influence of dry air (moisture - free air), ambient air, temperature and distilled water bath on stability of intercalated C-C composites has been analyzed. Stability of intercalated composites was determined in term’s relative change of resistivity, measured in time. To prepare the C-C composites two kinds of pitch-based fibres were used: P-120 and K-1100. Both types of fibres differed from each other in parameters of crystal structure (Tab. 1). As precursors of composite of matrices, phenol-formaldehyde resin (Z) and mesophase pitch (PAK), were used. After initial carbonisation, the carbon matrix was heated to 2150oC to improve ability to intercalation. Three kinds of composites, with two directional reinforcement (2D), P/Z, K/Z and K/PAK were prepared. Parameters of crystal structure have showed in Table 1. All carbon samples were intercalated with copper (II) chloride. Kind of samples and their resistivity after intercalation have shown in Table 2. Studies in dry air (Fig. 1) have showed that the higest changes in resistance occurred for composites with fibres P-120. For composites with fibres K-1100 the changes in resistance weren’t observed. During measurements in ambient air, the relative changes of resistance were generally higher (Fig. 2). A kind of fibre, which was used, has an impact on stability. High stability of composite reinforced with K-1100 results from its well ordered crystalline structure. Thermogravimetric analyses showed that the composites with fibres K-1100 had lower mass changes than the composites with fibres P-120 (Fig. 3, Tab. 3). No mass changes were observed up to 400oC, for the composites with fibres K-1100 intercalated with CuCl2. In all range of temperature the mass losses for these composites were from 14% to 16%, independently from the precursor of matrix. On the other hand, the composites with fibres P-120 undergo deintercalation even after slight increasing of temperature. In this case total mass losses have gained the value of 50%.