Release date: 2016-09-06
Research by Rice University scientists has shown that graphene solid flakes welded together can be used as materials for orthopedic implants.
Pullickel Ajayan, a material scientist at Rice Research in Texas, and colleagues used spark plasma sintering to weld sheets of graphene oxide to form a porous solid with mechanical properties that is comparable to titanium, a standard bone substitute.
The discovery was published in the journal Advanced Materials.
Researchers believe their technology uses graphite molds to make graphene in highly complex shapes in minutes, making bit metal processing easier.
“We started thinking about whether this could be used for bone implants, because graphene is one of the most interesting materials with many possibilities, it is generally biocompatible,†said Rice research assistant Chandra Sekhar Tiwary, Dibyendu Chakravarty The co-first author, he is from the direction of new materials for powder metallurgy at the Hyderabad Research Center in India. “Four things are important: mechanical properties, density, porosity and biocompatibility.â€
Tiwary says that spark plasma sintering is used industrially to make complex parts, typically used in ceramics. “This technology uses a high pulse current of the solder tab. You only need high voltage, no high voltage or high temperature,†he said. Nearly 50% of the material is porous, the density is half that of graphite, and it is one quarter of metallic titanium. But it has enough compressive strength of -40 MPa - which allows it to be used as a bone implant, he said. The bond strength between the sheets keeps it from disintegrating in the water.
“This example illustrates the possibility of using unconventional materials in combination with traditional technologies,†Ajayan said. “However, these transitions can only be made into 3D solids, such as 2D graphene layers, with appropriate density and strength.â€
“The engineering knots and strong interfaces between nano-building blocks are the biggest challenge to achieve these goals, but in this case, spark plasma sintering seems to be an effective means of producing a three-dimensional model of graphene sheets,†he said.
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Source: Noble
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