Surface Nanostructuring of Ti₄₀Cu₄₀Zr₁₁Fe₃Sn₃Ag₃ Amorphous Alloy by Chemical Dealloying for Potential Use as a Biocompatible Material

Amorphous alloys show potential as implant materials due to their superior mechanical properties and good corrosion resistance. However, the presence of toxic elements in the alloy composition can pose challenges, as they can react with the surrounding tissue, leading to inflammation and cell death. This study focuses on the design of a new Ti based multicomponent amorphous alloy for the development of biocompatible implant materials with enhanced hemocompatibility. Ti40Cu40Zr11Fe3Sn3Ag3 at% amorphous alloy was developed, with composition comprising biocompatible elements (Ti, Zr, and Sn) and antimicrobial elements (Ag, Fe, and Cu). While this class of amorphous alloys has shown its potential for biomedical implant applications, there are major concerns due to the presence of elements such as copper which can lead to cytotoxicity in the human body during long term implantation. Nevertheless, copper is indispensable in the development of an amorphous alloy. Thus, the objective of this work is to selectively remove copper from the surface of the Ti40Cu40Zr11Fe3Sn3Ag3 (at%) amorphous alloy using the dealloying technique using a solution of ammonium hydroxide and hydrogen peroxide and produce a patterned protective passivated surface rich in Ti and Zr oxides. The surface of the samples was analyzed using atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The modified surfaces show titanium oxide-rich nanostructured topography with depleted amounts of copper from the surface. The kinetics of the selective removal of copper, and the influence of parameters such as electrolyte concentration, immersion time, and stirring velocity on the evolution of morphology were investigated. Our findings elucidate the mechanism of pseudo-dealloying using an ammonia based solution and demonstrate its efficacy in enhancing the biocompatibility of the alloy. This study underscores the significance of our approach in tailoring the surface properties of amorphous alloys for biomedical applications, paving the way for their utilization in implant materials with improved biocompatibility.