A research team composed of Ph.D student Kento Katairi and Associate Professor Masayoshi Ozaki of the Graduate School of Engineering, Osaka University, Japan, and Professor Toruo Iriya of the Research Center for Deep Earth Dynamics of Ehime University, and others, has identified the strength of nano polycrystalline diamond during high-speed deformation.
The research team sintered the microcrystals with the largest size of tens of nanometers together to form a "nano polycrystalline" diamond, and then applied ultra-high pressure to it to investigate its strength. The experiment was carried out by using the laser XII with the largest pulse output power in Japan. When applied to less than 16 million atmospheres of the earth, the volume of the observed diamond shrinks by more than half.
The experimental data show that the strength of nano polycrystalline diamond (NPD) is more than twice that of single crystal diamond. It is also found that NPD has the highest strength of all the materials investigated so far.