Assessment of Ni ion release from TiTaHfNbZr high entropy alloy coated NiTi shape memory substrates in artificial saliva and gastric fluid

Abstract

NiTi shape memory alloy substrates were coated with TiTaHfNbZr high entropy alloy (HEA) thin films by RF magnetron sputtering, and then immersed into artificial salvia (AS) and gastric fluid (GF) solutions in order to evaluate the effectiveness of the HEA coating in preventing Ni ion release from the substrates. The findings demonstrate that the TiTaHfNbZr HEA coating significantly restricts Ni ion release from NiTi even when subjected to two very acidic body fluids (AS and GF), warranting a thorough examination of this material for utility as coating material in NiTi based biomedical applications.