Ataque básico como uma estratégia de modificação da superfície do Ti CP e da liga Ti-6AL-4V para aplicações como biomateriais

Abstract

Historically, biomaterials have been used to improve people's quality of life. Whether in the manufacture of prostheses, implants, contact lenses, pacemakers or in any application in its vast field of use, the search for the best biomaterial is constant. Each biomaterial has specific properties for use and titanium stands out mainly when used in the manufacture of implants and prostheses. In addition to commercially pure titanium, the Ti-6Al-4V alloy has become an interesting alternative due to its low reactivity characteristics in a biotic environment, ease of formation of hydroxyapatite on its surface, as well as good mechanical and corrosion resistance indices. However, even so, additional treatments on the metal are indicated to increase the chances of success of implants and prostheses. Several techniques are used to enhance the mechanical properties of the material and facilitate bone-implant adhesion. This is the case with basic etching, a treatment that aims to increase the surface roughness of the metal, creating a larger contact surface and intensifying the formation of hydroxyapatite and binding proteins. This study aims to chemically characterize commercially pure titanium and the Ti-6Al-4V alloy and analyze the influence that the exposure time and temperature have on the surface modification of the metal and its alloy through basic attack with NaOH (5 M) . For the present work, the temperature used was 25 °C and exposure of 6 hours, 14 hours, 24 hours and 137 hours. In addition to this temperature, a temperature of 80 °C and exposure time of 1 hour, 2 hours and 3 hours were also used. In the characterization, the technique of optical microscopy, scanning electron microscopy and profilometry was used to analyze the surface roughness, and the energy-dispersive spectroscopy sensor was used to characterize the chemical composition of the material used. The results show that carrying out the basic attack generates surface roughness (Sa), measured by the profilometer, reaching values of 0.679 μm in the Ti-6Al-4V sample that had the best result, and the highest roughness parameters were observed when submitted to attack at a temperature of 80ºC, and exposure time of 2h. For commercially pure titanium, the best result was obtained under the same conditions as the alloy (80ºC, for 2h), with a surface roughness of around 0.439 μm.