Influence Of ECAP And Heat Treatment On The Corrosion Resistance And Bioactivity Of CP-Ti

With the arrival of the global aging, people tend to pay more and more attention to the quality of medical products and instruments. Because of the high specific strength, high corrosion resistance and bioactivity, titanium and titanium alloys have been favored by clinical medicine. Pure titanium does not contain toxic alloying elements, and ECAP?equal channel angular pressing? processing can improve the mechanical properties of it. Recent studies show that ECAP treatment increases the corrosion resistance and biological activity of pure titanium, however, the understanding of the mechanism is still lacking.Based on the heat treatment and ECAP processing to CP-Ti? Commercial Pure Titanium?, this paper carries out two major experiments. First, the corrosion behavior of CP -Ti was researched by electrochemical test. The influence of different treatment processes on the corrosion resistance was analyzed by the Tafel curve and EIS? Electrochemical Impedance Spectroscopy?, combined with EBSD?electron back-scattered diffraction?. Second, the bioactivity of commercial pure titanium was studied after two months of immersion. XPS? X- ray photoelectron spectroscopy? was used for semi quantitative analysis and SEM? Scanning Electron Microscope? was used to observe the morphology of specimen surface, while EDS? Energy Dispersive Spectrometer? was used to analysis micro area composition.It is found that pure shear deformation occurred in pure titanium after ECAP treatment, the grain is refined with markedly directional. Cooled specimens produced the martensitic transformation, showing a fine lamellar structure. While organization of furnace cooled specimens is the most chaotic and has no direction. The corrosion resistance capacity of ECAPed specimens is best, and water cooled is better than furnace cooled specimens. There are a large number of TiO₂ and a small amount of Ti₂O₃ also a small quantity of Ca-P precipitate on the surface of the samples after immersing in simulated body fluid? SBF and BSA? two months. With the contents of O, Ca, P, and sediments observed by SEM, the number of Ca- P compounds deposited on the surface of ECAPed specimens is greater than that of furnace cooled and water cooled samples, which is believed to be the reason for the high corrosion resistance and bioactivity of ECAPed CP-Ti.