Chemical compatibility between the main components of two-phase heat transfer devices is of critical importance for correct operation and stability throughout the devices’ operational lifetime. The use of incompatible fluid-metal combinations can lead to corrosion and/or the generation of non-condensable gas (NCG), both of which result in reduction in heat transfer performance or complete device failure.
In order to verify working fluid and material compatibility, life-testing experiments are being conducted across a wide range of fluid-material combinations, with a particular focus on additively manufactured materials using the laser powder bed fusion process (PBF-LB/M). As this is a relatively new technology, the material’s compatibility with different fluids must be demonstrated before they can be used in future space applications. This work includes the design and manufacture of multiple thermosyphon devices, followed by ongoing long-term characterisation through gas plug testing. This involves applying an isothermal temperature to the device evaporator and monitoring, over an extended period of time, any change in condenser temperature, indicative of NCG generation. The project aims to provide recommendations of the successful fluid-metal combinations to the community.