Pressure generation to 65 GPa in a Kawai-type multi-anvil apparatus with tungsten carbide anvils

We have expanded the pressure ranges at room and high temperatures generated in a Kawai-type multi-anvil apparatus (KMA) using tungsten carbide (WC) anvils with a high hardness of Hv = 2700 and a Young’s modulus of 660 GPa. At room temperature, a pressure of 64 GPa, which is the highest pressure generated with KMA using WC anvils in the world, was achieved using 1°-tapered anvils with a 1.5-mm truncation. Pressures of 48–50 GPa were generated at high temperatures of 1600–2000 K, which are also higher than previously achieved. Tapered anvils make wide anvil gaps enabling efficient X-ray diffraction. The present pressure generation technique can be used for studying the upper part of the Earth’s lower mantle down to 1200 km depth without sintered diamond anvils.