multianvil

Multianvil refers to a class of high-pressure laboratory devices in which a pattern of multiple anvils compresses a central sample assembly to generate extreme pressures. The design allows the sample to be subjected to quasi-hydrostatic compression when the anvils are driven together by hydraulic or mechanical means. Multianvil systems are widely used in experimental geoscience and materials science to simulate conditions found deep in Earth’s interior and to synthesize materials under high pressure and temperature.

Most common configurations employ six, eight, or twelve anvils arranged around a central chamber. Anvils are typically made of very hard materials such as tungsten carbide. The sample sits in a gasketed assembly that includes a pressure medium, often MgO, to transmit load and shape the pressure. Heating is accomplished with resistive heaters, such as graphite, surrounding the sample or by induction heating, enabling simultaneous high pressure and high temperature conditions.

Operating ranges depend on the specific setup, but multianvil presses commonly achieve pressures up to about 25–30 gigapascals and temperatures on the order of 1500–2500 kelvin, with higher temperatures possible for short durations. The technique yields larger sample volumes than many diamond anvil cell experiments, making it well suited for studying phase transitions, equation-of-state behavior, mineral and ceramic synthesis, and other high-P–high-T phenomena.

Historically, multianvil technology advanced in the mid-20th century, with notable contributions from Japanese researchers developing the Kawai-type press, which enhanced reliability and throughput of high-pressure experiments. Today, multianvil devices complement diamond anvil cells by offering larger samples and accessible high temperatures at substantial, though lower, pressures. Limitations include lower maximum pressures compared with diamond anvils, potential deviations from perfect hydrostatic conditions at high pressure, and greater operational complexity and maintenance needs.