Design and performance of tapered cubic anvil used for achieving higher pressure and larger sample cell.

In order to increase the maximum cell pressure of the cubic high pressure apparatus, we have developed a new structure of tungsten carbide cubic anvil (tapered cubic anvil), based on the principle of massive support and lateral support. Our results indicated that the tapered cubic anvil has some advantages. First, tapered cubic anvil can push the transfer rate of pressure well into the range above 36.37% compare to the conventional anvil. Second, the rate of failure crack decreases about 11.20% after the modification of the conventional anvil. Third, the limit of static high-pressure in the sample cell can be extended to 13 GPa, which can increase the maximum cell pressure about 73.3% than that of the conventional anvil. Fourth, the volume of sample cell compressed by tapered cubic anvils can be achieved to 14.13 mm(3) (3 mm diameter × 2 mm long), which is three and six orders of magnitude larger than that of double-stage apparatus and diamond anvil cell, respectively. This work represents a relatively simple method for achieving higher pressures and larger sample cell.

Finite element analysis and design of cubic high-pressure anvils based on the principle of lateral support.

This article theoretically investigates the lateral support on cubic high-pressure anvil using finite element analysis. The results show that to gain the same chamber pressure, the value of system oil pressure can be decreased by reducing the lateral support area and the anvils' lifetime is extended when the lateral support area grows. The optimal lateral support area to maximize anvils' lifetime is 27.96 cm(2). Furthermore, the chamber pressure will increase by about 6.99% when the value of lateral support area reduces from 33.16 to 27.96 cm(2) under same hydraulic rams. Our simulation results have been verified by many high-pressure synthesis experiments and illustrated by breakage of anvils.

Hybrid-anvil: A suitable anvil for large volume cubic high pressure apparatus.

A hybrid-anvil used in cubic high pressure apparatus is presented, which makes it possible to pressurize samples of 36 mm(3) volume up to 5.5 GPa and to heat simultaneously up to 1350-1400 degrees C for routine operation. The hybrid-anvil has been designed based on the theory of multilayered pressure vessels and massive support, which can save weight about 60.00% compared to the traditional anvil. We note from 10 000 times of experiments that the rate of failure crack decreases about 16.67% and the cost of anvil saves about 66.40% after the modification of the anvil. This represents a relatively simple and inexpensive anvil for material synthesis and research.