Graphene reduces wear of alumina ceramic

Alumina has for a long time been used in biomedical applications such as load-bearing hip prostheses and dental implants, due to its high resistance to corrosion, low friction, high wear resistance and strength. As material science progresses and advanced materials penetrate into society, ceramics are also continuously being improved, especially in strength and durability.

In a most recent development, Graphenea researchers, together with collaborators from Russia and throughout Spain, have shown that the addition of graphene to alumina improves the ceramic's wear resistance and decreases friction. The result is expected to soon find its use in real products, as graphene and its derivatives seem to be biocompatible and in addition carry a low cost.

The paper entitled "Wear behavior of graphene/alumina composite", published in the journal Ceramics International, describes the study of dry sliding behavior of a graphene/alumina composite material and compares it to regular alumina. The wear rate of the advanced composite was 50% lower than that of pure alumina, while the friction coefficient was reduced by 10%. This finding is made even more astonishing by the fact that the concentration of graphene in the final product is only 0.22% by weight. The type of graphene used for the study is Graphenea's standard graphene oxide.

Graphene-enhanced alumina has in itself not been studied much, and in fact there are few examples in literature of tribological studies of any graphene-enhanced ceramics. Graphenea's team recently participated in a study that showed that the addition of a small amount of graphene to alumina makes the ceramic less prone to breaking under strain, while simultaneously improving electrical conductivity.

The present experiment measured wear and friction by sliding the graphene/alumina composite material over a simulated distance of 10km. The material is slid in a "tribometer", a machine that simulates sliding behavior by bouncing a ceramic (in this case also alumina) ball off the tested material. The tribometer precisely measures the friction and wear as it goes. Such test instruments are often used to study novel hip implant designs. The testing of the material in this standard industrial tribometer puts the research close to end-user products.