Prolate Tetragonal Anvil-Type High-Pressure Apparatus

A prolate tetragonal anvil, which enables an extension of the pressure chamber without a loss in the generated pressure was proposed and actually built. The necessary condition for an isotropic compression of the pressure medium was deduced. The observed deformation of the pressure medium was, however, rather nonuniform and the pressure medium was slightly elongated along the direction of the press ram load. The generated pressure, on the other hand, was slightly increased compared with a cubic anvil apparatus having the same size anvil top as that in the direction of the press ram load, probably due to a reduction in the friction between the anvil holder and the sliding plane. The system of a rectangular noncubic hexahedron anvil in which the influence of the friction is taken into consideration is also proposed.