Abstract: An improved capsule and method of use for processing materials or growing crystals in supercritical fluids is disclosed. The capsule is scalable up to very large volumes and provides for cost-effective processing. In conjunction with suitable high pressure apparatus, the capsule is capable of processing materials at pressures and temperatures of up to approximately 8 GPa and 1500° C., respectively.

Abstract: An apparatus to contain the reaction vessel in which gallium nitride crystals (henceforth referred to as bulk crystals) can be grown using the ammonothermal method at high pressure and temperature is disclosed. The apparatus provides adequate containment in all directions, which, for a typical cylindrical vessel, can be classified as radial and axial. Furthermore, depending on the specifics of the design parameters, the apparatus is capable of operating at a temperature up to 1,200 degrees Celsius, a pressure up to 2,000 MPa, and for whatever length of time is necessary to grow satisfactory bulk crystals. The radial constraint in the current disclosure is provided by using several stacked composite rings. The design of the apparatus is scalable to contain reaction volumes larger than 100 cubic centimeters.