Speaker
Description
After two decades of research devoted to the reinforcement of ceramic composites with carbon allotropes such as graphene or nanotubes, the scientific community has developed different preparation routes and has achieved some significant milestones. Moreover, new reinforcing phenomena models based on the classic fiber reinforcement theory of ceramic materials have been developed. Nevertheless, different experimental problems are not resolved yet and severe limitations are still hindering the improvement of the mechanical properties of this composites.
Reviewing the literature, it can be confirmed that some increases in certain mechanical properties have been achieved. For example, an increase in fracture toughness has been frequently reported for increasing carbon content, but only up to relatively low carbon contents, that is, contents below 1.5 wt.%. But, typically, the results show a dispersion of more than 200% that can be explained in terms of the diversity of the possible precursors and the different types of carbon allotropes used. In addition, the reinforcement effect is vanished for carbon contents above this 1.5wt.%, which suggests that the reinforcement could not be acting in the most effective way. In order to improve the reinforcing effect, very different manufacturing routes have been tried since it is known that the most critical issue is that the allotropes may be adequately incorporated into the ceramic matrix. This means that, for example, they must be completely dispersed because the presence of carbon aggregates prevents their contribution to mechanical reinforcement. Or they must be located inside the grains because they would not efficiently provide new reinforcement phenomena when located at the grain boundaries.
In summary, the achievements up to now are, in general, questionable, an adequate incorporation of carbon allotropes in the ceramic for the reinforcement to be maximum effective is still an experimental challenge.
| Speaker Country | Spain |
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