Aliasghar Behnamghader - Assistant Professor of Materials and Energy Research Center, Tehran, Iran.
Hoda Salemi - PhD student of Biomedical Engineering faculty Islamic Azad University, Science and Research Branch, Tehran, Iran. (Corresponding author)..
Abdollah Afshar - Professor of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran.
Mahmood Ardeshir - MSc student of Department of Biomedical Engineering, Islamic Azad University, Research and Science Branch, Tehran, Iran .

The chemical treatment in NaOH solution enhances the calcium phosphate precipitation on titanium substrates. The aim of this study was to investigate the topography and chemical modification of titanium substrates due to alkaline and heat treatment and their effects on the formation of calcium phosphate deposition in simulated body fluid solution. In this research, at first the titanium samples were treated with NaOH 5N and 10N and some of them followed a heat treatment at 600 ºC for 1 h. The samples were then immersed in the simulated body fluid (SBF) for 28 days to investigate the influence of surface treatments of titanium on in vitro bioactivity. The modified substrates were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). The in vitro assessment was carried out through the immersion of samples in simulated body fluid. According to the results obtained in this work, treatment in NaOH solution with a concentration of 5N led only to the formation of intragranular nanoporosities whereas the grain boundaries have been also affected with the increasing of the concentration to 10N. The pore size values increased due to the heat treatment at 600 ºC. The morphology analysis revealed the microstructure of coating was finer for the samples treated by NaOH 10N than ones treated by NaOH 5N.

alkaline and heat treatment; simulated body fluid; In vitro; Bioactivity; Titanium; Calcium phosphate