Formation of Nano/Micro Hierarchical Structures on Titanium Alloy Surface by a Novel Etching Solution

Abstract

A new effective oxidative solution for titanium (Ti) surface etching was recently developed. The present in vitro study was aimed at determining the influence of shorter (than 240 min) treatment time on the surface characteristics of the Ti nano/micro hierarchical structures. Cylinder-shaped Ti grade 5 alloys were etched for 30, 60, 120, and 240 min at room temperature and cleaned successively with acetone, ethanol, and distilled water in an ultrasonic bath. The micro- and nanostructures, surface roughness, dynamic wettability, and the surface elemental composition of the etched surfaces were evaluated. Nano/micro hierarchical structures, composed of micro-pits and nano-channels, were formed on the Ti surface through simple immersion in the oxidative solution. The findings suggest that the 120-min immersion yielded significant enhancement in the roughness and wettability of the Ti surfaces.

A super-hydrophilic surface enhanced by the hierarchical reticular porous structure on a low-modulus Ti–24Nb–4Zr–8Sn alloy

“…When the Control Ti2448 substrate was immersed in the mixed acid liquor, dissolution of the oxides and oxidation of the metal occurred. The microscale topography was consolidated and deepened through the following steps [31]: (i) partial oxidation of metal on sandblasted surfaces; (ii) dissolution of metallic oxides and oxidation of metal in the mixed heated dense acid liquor; and (iii) oxidation of metal on the acid-etched surfaces.…”

Effects of Surface Treatment Method Forming New Nano/Micro Hierarchical Structures on Attachment and Proliferation of Osteoblast-like Cells

“…When dental implants are used, it is important to achieve osseointegration, which refers to the direct connection between the implant surface and living bone without any soft tissue interference [ 2 ]. It is known that the surface topography of implants plays a critical role in the interaction between their surface and adjacent bone tissue [ 3 ], and early osseointegration is generally achieved through surface modifications, such as the modification of the chemical composition or surface roughness [ 4 , 5 ]. In particular, rough Ti surfaces have been found to elicit better osteoblast responses than smooth ones [ 6 ].…”

“…The presence of micron-sized surface structures facilitates robust mechanical interlocking between the implant and the surrounding bone, resulting in a significantly larger contact area for stable implant fixation [ 34 ]. In this method, sandblasted Ti implants with micron and submicron topographies are realized by immersing the implants in an etching solution consisting of concentrated sulfuric acid (H 2 SO 4 ) and hydrochloric acid (HCl) [ 3 ]. However, in the case of Ti-based alloys subjected to SLA, poor osteoblast adhesion in the early stages of the placement of the alloys poses a major problem [ 32 , 35 ].…”

“…However, in the case of Ti-based alloys subjected to SLA, poor osteoblast adhesion in the early stages of the placement of the alloys poses a major problem [ 32 , 35 ]. Furthermore, this technique involves the use of strong acids and heat; hence, it requires long and complex post-etching cleaning processes [ 3 , 36 ].…”

“…Recently, an eco-friendly Ti implant surface modification technique was developed. In this technique, a hydrogen peroxide (H 2 O 2 )/sodium bicarbonate (NaHCO 3 ) mixture is used as the immersing solution for Ti etching, instead of strong acids, such as H 2 SO 4 and HCl [ 3 , 36 ]. H 2 O 2 /NaHCO 3 solution has the advantage of being eco-friendly, and it can prevent the corrosion of alloys; moreover, in the solution, H 2 O 2 is not decomposed by NaHCO 3 [ 37 , 38 ].…”