Improvement of CNFs/ZrO2 composites properties with a zirconia nanocoating on carbon nanofibers by sol-gel method

The development of new carbon nanofibers-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 different chemical nature 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 carbon nanofibers nanocomposites CNFs/xZrO2 (x=20 vol.%) were prepared by powder mixture and a surface coating of CNFs by 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