Design Of The Hybrid Cell Assembly For Cubic Press And Its Pressure And Temperature Calibration

High-pressure physics is a discipline that studies the physical properties of materials under ultra-high pressure.It contains almost all research directions of condensed matter physics and is capable of a wide range of interdisciplinary studies with materials science,chemistry,geology,and many other disciplines.High-pressure equipment is the basis for high-pressure research.Among all high-pressure equipment,the cubic press is suitable for production of large-size samples under high-temperature and high-pressure conditions and is widely used in industrial production and various scientific research fields because of its excellent performances such as large sample chamber,simple operation,low cost,high production efficiency,etc.However,the pressure of the cubic press has been limited to less than 6 GPa,which seriously prevents it from playing a more important role,thus,it is of great significance to increase the pressure limit of cubic press without sacrificing the chamber size.This article mainly completed the following content:A newly hybrid cell assembly is designed for cubic press,that is,the pyrophyllite pressure-transmitting medium block is embedded with six Tungsten Carbide(WC)pressure-enhancing blocks,the pressure-enhancing block and the first-stage Tungsten Carbide(WC)anvil are separated by pyrophyllite to protect the anvil and heat preservation.The pressure calibration of the hybrid cell assembly and the conventional assembly of cubic press was completed.The pressure efficiency of the hybrid cell assembly is much higher the that of the conventional assembly,the reason is that the addition of the WC blocks greatly improves the overall bulk modulus of the pressure-transmitting block,and the higher the bulk Modulus,the higher the pressure efficiency.Secondly,it is found that the pressure limit of the conventional assembly is 6 GPa,which is consistent with the previous report,and the pressure of the hybrid cell assembly can be raised higher than 8 GPa or even 9 GPa.The temperature calibration experiments for both assemblies were also finished.It was found that the heating efficiency of the hybrid cell assembly is much lower,only 62% of the conventional assembly,because of the high thermal conductivity of WC.Nevertheless,the temperature of the hybrid cell assembly can easily reach 2500 ?,which is enough to meet the temperature requirements of most high-pressure studies.Ultrahard nano-polycrystalline c BN has been successfully synthesized by direct conversion of h BN above 8 GPa and 2000 ?.Using the newly designed cell,the cubic device can be rousingly and safely implemented above 8 GPa and 2500 ? with a centimetre-sized sample volume,which offers lots of new possibilities for discovery of new materials with advanced properties and exotic physics.