Rather than single crystal diamond, nano-polycrystalline diamond[1](npd) is probably an all-round better structural material, as you don't have to worry about t

Rather than single crystal diamond, nano-polycrystalline diamond[1](npd) is probably an all-round better structural material, as you don't have to worry about the cleavage planes of single crystals. Unfortunately, it can only be made at high pressure and temperature, and it requires significantly higher P (>20 GPa vs <10 GPa) and T than typical HPHT diamonds. That means (1) current HPHT apparatus cannot be used to make nano-polycrystalline diamond, and (2) it is unlikely that we will ever be able to make large single pieces, as large volumes at high pressure require very large presses. Synthetic industrial diamonds are typically made in China using hinge-type cubic anvil apparatus, whereas npd requires a Kawai-cell octahedral multi-anvil apparatus to reach higher pressure. Thus, the existing synthetic diamond infrastructre cant be used to make npd. The largest npd pieces reported in the literature are 15 x 15 mm cylinders, and they required a 6000 ton press. I don't want soccer-ball sized npd, just npd big enough, (as well as cheap and readily available) to make typically-sized anvils for high pressure apparatus. It is stronger than tungsten carbide, so it can go to higher pressures, and it is relatively transparent to x-rays, so it is easy to make in situ measurements. Widespread availability of such material would significantly change high pressure research. [1] http://www.grc.ehime-u.ac.jp/en/prius/facilities/himedia http://www.grc.ehime-u.ac.jp/en/prius/facilities/himedia