This Small Business Innovative Research Phase I project will address sintering of `binderless` Nanocrystalline Diamond Compacts (NDCs). Sintering will be performed using an advanced high pressure/high temperature synthesis method with capabilities of 15 GPa at 1800 oK. Currently. Polycrystalline Diamond Compacts (PDCs) are produced commercially from 20-70 micron size diamond powder by high pressure compaction methods, using metal binders (Co, Si Ni). Use of the metal binder reduces the thermal stability of the compacts, while use of large diamond powder particles reduces the toughness and ductility. This limits the applications for the PDCs. This project will develop an economical method for fabricating Nanocrystalline Diamond Compacts (NDCs), without any binder from < 5 nm diamond particle powders. The hardness and toughness of the material should match those of naturally formed polycrystalline diamond - `carbonado`. The ultra-fine grained diamond compacts are candidate materials for precision manufacturing tools, which can be used for high rate machining and fabrication of hard materials. The project will demonstrate the feasibility of producing test samples of NDCs using highly purified nano-diamond powder as starting material, and our in-house ultrahigh pressure unit for powder compaction purposes. This project will determine the physical and mechanical properties of the NDC samples. Routine production of large volumes of binderless nanocrystalline diamond compacts will significantly improve the high temperature stability and precision performance of cutting tools.
