A chemical patterning approach of dense and porous titanium surfaces by using a combination of concentrated acid and oxidant

Abstract

Commercially dense pure titanium sheets and porous titanium samples processed by powder metallurgy were treated with a mixture consisting of equal volumes of H 2 SO 4 and H 2 O 2 for 2 or 4 hours. Characterization was performed by scanning electron microscopy, energy dispersive X-ray spectroscopy, confocal scanning optical microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The analyses showed that the chemical patterning approach using a combination of concentrated acid and oxidant was able to generate a nanotexture on dense and porous titanium surfaces. In addition, the treated samples presented an oxide layer consisting predominantly of titanium dioxide with negative charge conferred by the presence of hydroxyl groups, which is an important factor that favors apatite nucleation and protein adsorption. It was also observed that oxide formation was more effective on porous samples than on dense samples, which can be explained by the higher surface area intrinsic to porous media. Finally, the findings indicated that both treatment times promoted similar modifications in surface properties, such as nanotexture and chemical composition, suggesting that the time of 2 hours were enough to induce the surface alterations at the nanoscale.

Study of the influence of titanium and niobium particle size on the Ti35Nb alloy production with controlled porosity

“…Although oxygen is a α-Ti phase stabilizer, its presence in the initial powders did not harm β-Ti phase stabilization, as observed in Figure 6. However, the presence of oxide layer on metal implant surface enhances the biocompatibility and kinetics of the bone formation process, because it avoids or reduce the diffusion of Ti or Nb ions from the bulk metal [43]. The phase composition of samples determined by Rietveld refinement is shown in Table 4.…”

“…The higher Ra and standard deviation values exhibited by MA sample are related to the presence of macropores on the surface, which makes the roughness profile more heterogenous. Both samples presented suitable surface roughness parameters for bone implant applications, since studies have demonstrated that surfaces with Ra > 10 µm are able to help in initial implant stability and improve osseointegration [43]. Further, large surface roughness favors the adhesion of bioceramic coatings deposited on metal substrates [18].…”