Estudo da influência do cobre em ligas ternárias de NiTiCu para utilização em biomateriais.

Abstract

The use of Nitinol alloys (NiTi) are extremely important in the manufacture of biomedical devices, for combining the unique characteristics of such alloys and superelasticity and shape memory effect. Due to the high concentration of nickel in alloys of NiTi, it is theoretically possible dissolution of nickel in body fluids as a result of corrosion processes, which may cause unwanted effects. The phenomena of biocompatibility and biotoxicity of NiTi have been thoroughly studied, thus aiming to minimize the damage from the use of these materials. As a result of these studies, it was proposed in this research work to decrease in metal concentration in nickel NiTi alloys and their replacement by copper metal, thereby forming an alloy NiTiCu. Electrochemical techniques were used to observe the corrosion and features found in each league NiTiCu with different composition and compare them with the NiTi for a better approach to the problem and identify the similarities and differences perceived between the studied alloys, as well as a comparison surface of the material with the use of scanning electron microscopy techniques, Differential Scanning Calorimetry and Microhardness of Vicks. The electrochemical behavior of the alloys of NiTi and NiTiCu were studied using electrochemical techniques Linear Polarization, Cyclic Voltammetry and Electrochemical Impedance in two corrosive media Hanks solution (artificial blood) and Solution Saliva Artificial that closely resemble the bodily conditions areas of use of these biomaterials, at an ambient temperature of about 25 ° C to check the durability of metal alloy. It was observed that the higher the concentration of copper in the alloy NiTiCu less corrosion-resistant the material will have. In the superficial characterization, it appears that the alloys containing the lowest concentration of copper, have surface characteristics that are more similar to the conditions of NiTi alloys are widely utilized in biomedical devices. With the analysis of all electrochemical tests and superficial and structural characterization of metal alloys NiTiCu and NiTi, it is found that alloys containing NiTiCu with copper percentages small close to 5%, have similar characteristics of NiTi, favoring possible use of this ternary alloy NiTiCu for the production of biomaterials for medicine and dentistry, provided there is wider and interdisciplinary studies for detailed analysis regarding biocompatibility, biotoxicity and mobile development of this new alloy.