3424 Mechanical properties of nano-polycrystalline diamond
Details
High-purity nano-polycrystalline diamond (NPD) has been successfully synthesized through direct conversion from graphite under a pressure of 15 GPa and a temperature of 2300 ℃. The NPD consists of nano-diamond particles (<100 nm) and containing no secondary phases. The Knoop hardness of NPD at room temperature is as high as 120-140 GPa, which is equivalent to or even higher than those of single-crystal diamonds. The high temperature hardness of NPD at high temperatures (>800 ℃) is about 2 times higher than those of single-crystal diamonds. The wear rate of NPD is less than one-tenth of those of conventional polycrystalline diamond containing metal binders. These salient characteristics permit us to apply the large NPD to a wide field of industrial and scientific applications such as high-precision cutting tools, abrasion-resistant materials, optical windows, high-pressure anvils.
