Surface nanostructuring of Ti40Cu40Zr11Fe3Sn3Ag3 amorphous alloy by alkaline chemical treatment for potential use as a biocompatible material

Abstract

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. To address this, Ti40Cu40Zr11Fe3Sn3Ag3 at% amorphous alloy is developed. This composition comprises of biocompatible elements (Ti, Zr, and Sn) and antimicrobial elements (Ag, Fe, and Cu), for potential use as implant materials. Chemical pseudo-dealloying using a solution of ammonium hydroxide and hydrogen peroxide is employed to selectively remove copper from the sample surface, which may induce toxicity by prolonged contact, and promote the formation of a patterned passivating Ti/Zr oxide-rich surface to enable possible antimicrobial effects. 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. In detail, the pseudo-dealloyed samples exhibited hydrophilic interactions and demonstrated hemocompatibility, making them promising candidates for blood-contacting medical devices. 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.