Next generation polycrystalline diamond
PI: Todd, Richard
The proposal concerns synthetic polycrystalline diamond (PCD), which is an extremely hard material currently used mainly for drilling through rock. The proposal stems from previous research in the Department of Materials that was funded mainly by EPSRC with additional contributions from Element Six UK Ltd, who are the partner in this proposal.
Our previous research shows that increasing the strength of the so-called metallic ""binder"" in PCD (actually a processing additive) will solve two distinct problems in its application and lead to a step-change improvement in properties. This will enable the benefits of these extraordinary materials to be extended to a much wider range of applications, for which current PCD is not sufficiently durable. These include mining, tunnel boring and other civil engineering applications. The impact is potentially enormous, benefitting Element Six UK as well as leading to increased efficiency for a wide range of UK industries and reduced costs for consumers. New IP will be generated that will be exploited by Oxford University and Element Six under a new IP agreement. The purpose of this proposal is to provide ""proof of concept"" so that the route to application is cleared.
The concept will be demonstrated by adjusting the composition of the existing binders to increase their strength using well-established knowledge from the aerospace industry. The first problem this will solve is that when cutting through rock, the surface of the PCD becomes sufficiently hot to transform to graphite, severely increasing the wear rate and in extreme cases causing failure. Our previous research shows that a stronger binder will constrain and thus prevent this transformation. The second problem concerns compressive residual stresses that are designed into the PCD cutters, suppressing the growth of cracks during operation. Our research shows that these stresses will also be substantially increased by a stronger binder, improving the life of the cutters.