Any comparisons with the other foams in mechanical properties and thermal properties ? Do they come in coated forms and who are the suppliers in India ?
It all depends on their porosity and how they were prepared. As a result, extremely different materials can be obtained, from very fragile thermal insulators to very strong thermal conductors. Mechanical and thermal properties can indeed differ by several orders of magnitude depending on precursor, thermal history and preparation mode. I am not aware of suppliers in India but there are in USA.
Alain
Hi, I could perhaps answer you about mechanical properties. In general you have density scaling relations that can be used to estimate mechanical properties of a porous material. This scaling laws are very important to drive the choice of a structural material.
So, the first paper that I would read if I were You is this, very very important:
Ashby, M., 2006. The properties of foams and lattices. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, 15–30. URL: http://dx.doi.org/10.1098/rsta.2005.1678, doi:10.1098/rsta.2005.1678
Once you have clear density scaling relations, that for foams are essentially always the same, you can pass to the next point. Before this, we can say something about density scaling relations for foams. In particular You will find that in general foams present a quadratic density scaling relation like this (here for Young modulus for, for example, gold):
E(porous gold)/ E(gold)=(Density(porous gold)/Density(gold))2
This kind of quadratic relation is due to the fact that the structure of foams is in general "bending dominated", essentially the main failure mechanisms is the bending of the branches. This behavior is related to the fact that foams presents in general a small connectivity at the nodes, three or four branches for each node. For example, microtrusses present in general a linear scaling relation due to the higher connectivity at the nodes.
Ok, after that You can pass to graphene, graphite and carbon foams. In particular I
recommend You this paper "Multi-scale intrinsic deformation mechanisms of 3D graphene foam" Andy Nietoa, Benjamin Boesla, Arvind Agarwala http://www.sciencedirect.com/science/article/pii/S000862231500010X
This paper, is, for me, one of the best. You'll find there the use of density scaling relation and an experimental measure of the "intrinsic" properties of the graphite layers that compose the branches of the foams.
After that You can pass to carbon-based foams, I recommend You this paper
Celzard, A., Zhao, W., Pizzi, A., Fierro, V., 2010. Mechanical properties of tannin-based rigid foams undergoing
compression. Materials Science and Engineering: A 527, 4438 – 4446. URL: http://www.sciencedirect.com/
science/article/pii/S0921509310003783, doi:http://dx.doi.org/10.1016/j.msea.2010.03.091.
This paper explores in a very good way the mechanical properties of carbon foams, using more refined models than Ashby scaling laws.
In the end, if you want check something on graphene foams, or better, carbon nanotruss networks, you can refer to two paper, one of my research group, on arXiv
Designing graphene-based nanofoams with nonlinear auxetic and anisotropic mechanical properties under tension or compression
Andrea Pedrielli, Simone Taioli, Giovanni Garberoglio, Nicola Pugno
arXiv:1606.05494 [cond-mat.mes-hall]
This paper is a computational study of mechanical properties of periodic graphene foams (nanotruss networks), using molecular dynamics and AIREBO potential. You are invited to check the paper for the details, but, essentially we can say that foams with nanometric pores and high connectivity between the pores, for example 12 nearest neighbors for each pores, presents a young modulus similar to those of aluminium. You can also have a negative Poisson ratio, or other interesting properties.
Foam similar to those of our paper can be realized using for example, stacked silica nanoparticles on which You can grow graphene. A paper in which is reported this procedure is the following:
Yoon, J.C., Lee, J.S., Kim, S.I., Kim, K.H., Jang, J.H., 2013. Three-dimensional graphene nano-networks with high quality and mass production capability via precursor-assisted chemical vapor deposition. Scientific Reports 3.
URL: http://dx.doi.org/10.1038/srep01788, doi:10.1038/srep01788.
The stacked nanoparticles used in this article are disposed in an face centered cubic fashion, that permits an higher connectivity between the pores and, in general a more rigid structure in respect to standard foams.
Due to the inspiration that the following paper gave to us for our work on nanotruss networks, and because is one of the very few paper on this topic from a computational point of view, I invite You to check also this good paper:
Wu, J., He, J., Zhang, Z., 2013. Fracture and negative Poisson’s ratio of novel spanned-fullerenes nanotube networks under tension. Computational Materials Science 80, 15–26. URL: http://dx.doi.org/10.1016/j.commatsci.
2013.04.033, doi:10.1016/j.commatsci.2013.04.033.
You can find some other references in our paper, that in some way attempts to attack the problem of mechanical properties of graphene foams.
To conclude, if with "structural applications" You mean something like "structural engineering applications" and you are searching for mechanical properties comparable with, for example, steel, You should consider high density foams with small pores and high connectivity at the nodes.
Regards,
Andrea
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