Ceramic materials like alumina have been used for thousands of years, and are now used extensively in hi-tech applications such as semiconductors.
Alumina is an oxide of aluminium, which exhibits low friction, high strength, and high resistance to wear and corrosion. These properties make it suitable for biomedical applications such as dental implants and load-bearing hip prostheses
Continuous development in advanced materials is constantly improving the properties of ceramics, especially durability and strength.
In a recent study, researchers from Graphenea, in collaboration with scientists from Spain and Russia, have demonstrated a method for improving the wear resistance and lowering the friction of alumina by adding graphene. Considering the biocompatibility and low cost of graphene and its derivatives, practical applications of this method should be relatively easy to implement.
In this study, dry sliding behavior of a graphene/alumina composite material was compared against regular alumina. The results of the study were reported in the Ceramics International journal under the title “Wear behavior of graphene/alumina composite.”
To measure friction and wear, the graphene/alumina composite material was made to slide over a simulated distance of 10km in a “tribometer,” where sliding behavior is simulated by bouncing a ceramic ball off the material of interest.
The tribometer accurately measured the wear and friction experienced by the tested material. Such test equipment is typically employed to investigate novel hip implant designs. The use of this standard industrial tribometer for testing the material of interest puts the research in line with end-user products.
The results revealed that the wear rate and the friction coefficient of the graphene/alumina composite material were lower than that of pure alumina by 50% and 10%, respectively (Figure 1). In addition, the most surprising fact was that the graphene concentration in the final product is a mere 0.22% by weight. Graphenea's standard graphene oxide was used for this study.
Figure 1. The addition of graphene to alumina halves the wear rate (copyright Elsevier)
This study shows that small amounts of graphene additive can drastically enhance the properties of alumina. This graphene-enhanced composite material could be used to create more durable hip joint prosthetics, and other ceramic components where a low wear-rate is desirable.
There are only a few studies on graphene-enhanced alumina and few tribological studies of graphene-enhanced ceramics to be found in the literature. In another recent study, Graphenea's team demonstrated that alumina can also be made to be less susceptible to rupturing under strain, and that it's electrical conductivity can be improved, by adding trace amounts of graphene.
This information has been sourced, reviewed and adapted from materials provided by Graphenea.
For more information on this source, please visit Graphenea.