Corrosion Attack of Liquid Gallium Alloy on Structural Materials

The SARAF (Soreq Applied Research Accelerator Facility) Phase II the Beam Dump is designed to extract power of 200 kW achieved by 40 MeV protons /deuterons under current of 5 mA. To avoid radiation damage and improve heat transfer a design concept of liquid metal target is suggested. The suggested liquid is a Ga-In-Sn metal alloy (Gallinstan) with a melting point of 10oC. This liquid metal is used in other applications for dissipating concentrated heat loads such as thermal interfaces for microprocessors, reactors and heat exchangers. However, gallium alloys will attack some metals even at room temperature. At high temperatures gallium dissolves most metals but not all. For structural metals of the heat exchanger, some candidate metals that are considered to have good resistant corrosion by Galinstan at moderated temperatures, have been exposed to 150oC during hundreds of hours to characterize the attacked surface.

The chosen metals were austenitic nickel-chromium-based alloy Inconel® 625, pure tantalum and the austenitic SS 316 L.

The surface of the attacked metals was systematically characterized by optical microscope, weight lost, SEM and EDAX analysis.

References

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