Thermophysical properties of liquid Zr52.5Cu17.9Ni14.6Al10Ti5—prospects for bulk metallic glass manufacturing in space

Bulk metallic glasses are of critical interest for a wide range of applications, including their use in spacecraft gearboxes and mechanisms due to their excellent low-temperature, unlubricated wear resistance. Also of interest, is the potential for in-space manufacturing of metal alloys and the use of microgravity to determine fundamental thermophysical properties to inform ground-based modeling and experimentation. In this work, a Zr-based bulk metallic glass was processed in the electromagnetic levitator ISS-EML to determine undercooling, electrical resistivity, specific heat capacity, surface tension, and viscosity. A 6.5 mm sphere was vitrified during the processing, resulting in the first bulk metallic glass manufactured on board the international space station (ISS).

Brush Plated Multilayered Cu/Ni Coating from a Single Electrolyte and its Fretting Wear Behaviors

Brush plated of Cu/Ni multilayer coating from a single sulfate electrolyte was prepared. The influence of applied voltage on the composition of the deposit and deposition rate was investigated to optimize the plating parameters. Wear tests were carried out in ball-on-plate geometry unlubricated. Wear scar morphology was observed using scanning electron microscopy and optical microscopy. It was found that the brush plated multilayer coating was highly dense and free from porosity. The multilayer coating showed less wear than Ni coating brush plated from the same solution. The increase in the wear resistance of the multilayer coating was attributed to lubricating effect of the transform film formed by Cu wear particles.