Improvement of Carbon Nanofibers/ZrO2 Composites Properties with a Zirconia Nanocoating on Carbon Nanofibers by Sol–Gel Method

The development of new carbon nanofibers (CNFs)–ceramic nanocomposite materials with excellent mechanical, thermal, and electrical properties is interesting for a wide range of industrial applications. Among the ceramic materials, zirconia stands out for their excellent mechanical properties. The main limitations in the preparation of this kind of nanocomposites are related with the difficulty in obtaining materials with homogeneous distribution of both phases and the dissimilar properties of CNFs and ZrO2 which causes poor interaction between them. CNFs-reinforced zirconia nanocomposites ZrO2/xCNFs (x=1–20 vol%) were prepared by powder mixture and sintered by spark plasma sintering (SPS). ZrO2-reinforced CNFs nanocomposites CNFs/xZrO2 (x=20 vol%) were prepared by powder mixture and a surface coating of CNFs by the wet chemical route with zirconia precursor is proposed as a very effective way to improve the interaction between CNFs and ZrO2. After SPS sintering, an improvement of 50% in fracture strength was found for similar nanocomposite compositions when the surface coating was used. The improved mechanical properties of these nanocomposites are caused by stronger interaction between the CNFs and ZrO2.This work was financially supported by National Plan Projects MAT2006-01783 and MAT2007-30989-E and the Regional Project FICYT PC07-021. A. Borrell, acknowledges the Spanish Ministry of Science and Innovation for her research grant BES2007-15033.Borrell Tomás, MA.; Rocha, VG.; Torrecillas, R.; Fernandez, A. (2011). Improvement of Carbon Nanofibers/ZrO2 Composites Properties with a Zirconia Nanocoating on Carbon Nanofibers by Sol–Gel Method. Journal of the American Ceramic Society. 94(7):2048-2052. https://doi.org/10.1111/j.1551-2916.2010.04354.xS20482052947Iijima, S. (1991). Helical microtubules of graphitic carbon. Nature, 354(6348), 56-58. doi:10.1038/354056a0Merkoçi, A. (2005). Carbon Nanotubes in Analytical Sciences. Microchimica Acta, 152(3-4), 157-174. doi:10.1007/s00604-005-0439-zUchida, T., Anderson, D. P., Minus, M. L., & Kumar, S. (2006). Morphology and modulus of vapor grown carbon nano fibers. Journal of Materials Science, 41(18), 5851-5856. doi:10.1007/s10853-006-0324-0Hvizdoš, P., Puchý, V., Duszová, A., & Dusza, J. (2010). Tribological behavior of carbon nanofiber–zirconia composite. Scripta Materialia, 63(2), 254-257. doi:10.1016/j.scriptamat.2010.03.069Balázsi, C., Kónya, Z., Wéber, F., Biró, L. P., & Arató, P. (2003). Preparation and characterization of carbon nanotube reinforced silicon nitride composites. Materials Science and Engineering: C, 23(6-8), 1133-1137. doi:10.1016/j.msec.2003.09.085Tatami, J., Katashima, T., Komeya, K., Meguro, T., & Wakihara, T. (2005). Electrically Conductive CNT-Dispersed Silicon Nitride Ceramics. Journal of the American Ceramic Society, 88(10), 2889-2893. doi:10.1111/j.1551-2916.2005.00539.xHirota, K., Hara, H., & Kato, M. (2007). Mechanical properties of simultaneously synthesized and consolidated carbon nanofiber (CNF)-dispersed SiC composites by pulsed electric-current pressure sintering. Materials Science and Engineering: A, 458(1-2), 216-225. doi:10.1016/j.msea.2006.12.065Dusza, J., Blugan, G., Morgiel, J., Kuebler, J., Inam, F., Peijs, T., … Puchy, V. (2009). Hot pressed and spark plasma sintered zirconia/carbon nanofiber composites. Journal of the European Ceramic Society, 29(15), 3177-3184. doi:10.1016/j.jeurceramsoc.2009.05.030Lee, S.-Y., Kim, H., McIntyre, P. C., Saraswat, K. C., & Byun, J.-S. (2003). Atomic layer deposition of ZrO2 on W for metal–insulator–metal capacitor application. Applied Physics Letters, 82(17), 2874-2876. doi:10.1063/1.1569985Kobayashi, S., & Kawai, W. (2007). Development of carbon nanofiber reinforced hydroxyapatite with enhanced mechanical properties. Composites Part A: Applied Science and Manufacturing, 38(1), 114-123. doi:10.1016/j.compositesa.2006.01.006Sun, J., Gao, L., Iwasa, M., Nakayama, T., & Niihara, K. (2005). Failure investigation of carbon nanotube/3Y-TZP nanocomposites. Ceramics International, 31(8), 1131-1134. doi:10.1016/j.ceramint.2004.11.010Ukai, T., Sekino, T., Hirvonen, A. T., Tanaka, N., Kusunose, T., Nakayama, T., & Niihara, K. (2006). Preparation and Electrical Properties of Carbon Nanotubes Dispersed Zirconia Nanocomposites. Key Engineering Materials, 317-318, 661-664. doi:10.4028/www.scientific.net/kem.317-318.661Duszová, A., Dusza, J., Tomášek, K., Morgiel, J., Blugan, G., & Kuebler, J. (2008). Zirconia/carbon nanofiber composite. Scripta Materialia, 58(6), 520-523. doi:10.1016/j.scriptamat.2007.11.002Wang, X., Padture, N. P., & Tanaka, H. (2004). Contact-damage-resistant ceramic/single-wall carbon nanotubes and ceramic/graphite composites. Nature Materials, 3(8), 539-544. doi:10.1038/nmat1161Zhan, G.-D., Kuntz, J. D., Garay, J. E., & Mukherjee, A. K. (2003). Electrical properties of nanoceramics reinforced with ropes of single-walled carbon nanotubes. Applied Physics Letters, 83(6), 1228-1230. doi:10.1063/1.1600511Yucheng, W., & Zhengyi, F. (2002). Study of temperature field in spark plasma sintering. Materials Science and Engineering: B, 90(1-2), 34-37. doi:10.1016/s0921-5107(01)00780-2Haase, F., & Sauer, J. (1998). The Surface Structure of Sulfated Zirconia:  Periodic ab Initio Study of Sulfuric Acid Adsorbed on ZrO2(101) and ZrO2(001). Journal of the American Chemical Society, 120(51), 13503-13512. doi:10.1021/ja9825534Matsui, K., Suzuki, H., Ohgai, M., & Arashi, H. (1995). Raman Spectroscopic Studies on the Formation Mechanism of Hydrous-Zirconia Fine Particles. Journal of the American Ceramic Society, 78(1), 146-152. doi:10.1111/j.1151-2916.1995.tb08374.xGateshki, M., Petkov, V., Williams, G., Pradhan, S. K., & Ren, Y. (2005). Atomic-scale structure of nanocrystallineZrO2prepared by high-energy ball milling. Physical Review B, 71(22). doi:10.1103/physrevb.71.224107Pyda, W., Haberko, K., & Bulko, M. M. (1991). Hydrothermal Crystallization of Zirconia and Zirconia Solid Solutions. Journal of the American Ceramic Society, 74(10), 2622-2629. doi:10.1111/j.1151-2916.1991.tb06810.xDell’Agli, G., & Mascolo, G. (2000). Hydrothermal synthesis of ZrO2–Y2O3 solid solutions at low temperature. Journal of the European Ceramic Society, 20(2), 139-145. doi:10.1016/s0955-2219(99)00151-xTai, C. Y., Hsiao, B.-Y., & Chiu, H.-Y. (2007). Preparation of silazane grafted yttria-stabilized zirconia nanocrystals via water/CTAB/hexanol reverse microemulsion. Materials Letters, 61(3), 834-836. doi:10.1016/j.matlet.2006.05.068Tai, C. Y., Lee, M.-H., & Wu, Y.-C. (2001). Control of zirconia particle size by using two-emulsion precipitation technique. Chemical Engineering Science, 56(7), 2389-2398. doi:10.1016/s0009-2509(00)00454-1Tai, C. Y., & Hsiao, B.-Y. (2005). CHARACTERIZATION OF ZIRCONIA POWDER SYNTHESIZED VIA REVERSE MICROEMULSION PRECIPITATION. Chemical Engineering Communications, 192(11), 1525-1540. doi:10.1080/009864490896133Ci, L., Wei, J., Wei, B., Liang, J., Xu, C., & Wu, D. (2001). Carbon nanofibers and single-walled carbon nanotubes prepared by the floating catalyst method. Carbon, 39(3), 329-335. doi:10.1016/s0008-6223(00)00126-3Choi, S. R., & Bansal, N. P. (s. f.). Alumina-Reinforced Zirconia Composites. Handbook of Ceramic Composites, 437-457. doi:10.1007/0-387-23986-3_18Li, W., & Gao, L. (2000). Rapid sintering of nanocrystalline ZrO2(3Y) by spark plasma sintering. Journal of the European Ceramic Society, 20(14-15), 2441-2445. doi:10.1016/s0955-2219(00)00152-7Borrell, A., Fernández, A., Merino, C., & Torrecillas, R. (2010). High density carbon materials obtained at relatively low temperature by spark plasma sintering of carbon nanofibers. International Journal of Materials Research, 101(1), 112-116. doi:10.3139/146.110246Dusza, J., Morgiel, J., Tatarko, P., & Puchy, V. (2009). Characterization of interfaces in ZrO2–carbon nanofiber composite. Scripta Materialia, 61(3), 253-256. doi:10.1016/j.scriptamat.2009.03.052Lauwers, B., Kruth, J. P., Liu, W., Eeraerts, W., Schacht, B., & Bleys, P. (2004). Investigation of material removal mechanisms in EDM of composite ceramic materials. Journal of Materials Processing Technology, 149(1-3), 347-352. doi:10.1016/j.jmatprotec.2004.02.01

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

The influence of the preparation route and composition on carbon nanofibers-silicon carbide (CNFs/SiC) nanocomposites' properties was studied. Nanopowders were mixed by ultrasonic dispersion or high attrition milling and the consolidation was done by pulsed electric-current pressure sintering technique. The relative density and fracture strength of high-energy attrition milled CNFs/SiC nanocomposites gradually increased with the increase of sintering temperature, from 1400 to 1800 degrees C and holding time 1 to 30 min. A chemical surface coating of CNFs with alumina precursor is proposed as a very effective way for improving the interaction between CNFs and SiC. An increase of 54% in fracture strength was achieved on the nanocomposites when the surface coating was used. As a consequence of the stronger interaction between the components, which is achieved through the use of suitable processing route and sintering parameters, and the role of nano-alumina as sintering aid improved mechanical properties was achieved. (c) 2012 Elsevier B.V. All rights reserved.This work has been carried out with the financial support of the National Plan Projects nos. MAT2006-01783 and MAT2007-30989-E and the Regional Project no. FICYT PC07-021. A. Borrell, acknowledges the Spanish Ministry of Science and Innovation for her Juan de la Cierva contract (no. JCI-2011-10498).Rocha, VG.; Borrell Tomás, MA.; Torrecillas, R.; Fernandez, A. (2012). Improvement of CNFs/SiC nanocomposites properties obtained from different routes and consolidated by pulsed electric-current pressure sintering. Materials Science and Engineering: A. 556:414-419. https://doi.org/10.1016/j.msea.2012.07.006S41441955

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