Additive manufacturing multiscale ultrahigh strength and high accuracy nanocrystalline nickel structures and components using ultrafine anode scanning through-mask electrodeposition

Abstract

Through-mask electrodeposition (TM-ECD) is a widely-used technique for manufacturing mesoscale and microscale precision metal features and components in a mass-production manner. However, in most cases, the traditional TM-ECD processes are very hard to fabricate high-accuracy multiscale (macroscale, mesoscale, microscale) features simultaneously due to the inherent nonuniform distribution of the applied energy fields including electric field, mass transportation field, and temperature field during electrodeposition. Furthermore, nanocrystalline microstructures have not been realized by TM-ECD without additional nonmetallic additives or mechanical stirring. Here, a ultrafine anode scanning through-mask electrodeposition (UASTM-ECD) process operated at DC mode is developed to further trigger the formation of nanocrystalline without additives, in which a ultrafine wire-shaped inert anode embedded in a stirring paddle reciprocates over the top surfaces of the through-masks with a spacing of less than 100 μm. Experimental investigations into this unique TM-ECD were systemically carried out by examining the geometrical profile, surface morphologies, forming accuracy, grain size, and mechanical properties of the fabricated nanocrystalline structures and components. Our findings showed that the UASTM-ECD can facilitate to achieve a significantly improved thickness distribution uniformity and considerably fine nanocrystalline ultrapure microscale and mesoscale complex cross-sectional arrays components over the traditional TM-ECD processes even though the multiscale features and components are simultaneously deposited on the same substrate. These result from the unique deposition manner of the UASTM-ECD in which the metal materials are intermittently filled into the patterned photoresist cavity molds very locally and at the extremely high current densities. This versatile approach eliminates the possible contamination by additives and integration difficulty of mechanical stirring, which can be used to fabricate the multiscale ultrahigh strength and high accuracy ultrapure nanostructured-material features.