Corrosion Behavior of Advanced Titanium Alloys in Saline Solutions
Authors:Danielle Noriega , Ryan Oh, Ian Ramos, Ayaka Tsuboyama, Zachary Weber Reitz
Mentor:Vilupanur Ravi, Professor and Chair, Chemical and Materials Engineering , California State Polytechnic University Pomona
Structural biomedical implants are of increasing importance as the world’s population rapidly ages. Improving implant lifetimes will be an ongoing and important factor in containing burgeoning health care costs. Therefore, the search for biocompatible and durable implants is an active area of biomaterials research. Research at Cal Poly Pomona has been progressing on two parallel fronts – corrosion resistance and biocompatibility – for a series of new titanium alloys. These alloys contain boron as the alloying element and can broadly be divided into titanium-based and titanium-aluminum-vanadium based alloys. We are using two distinct tests to determine the corrosion behavior of these alloys. One of these is a cyclic potentiodynamic polarization test and the other is a modified version of the F2129 biological compatibility standard. In the former case, the material is subjected to an aggressive range of electrical potentials, far higher than is likely to be encountered in the human body, so that the breakdown behavior of the different alloys can be distinguished. In the latter case, i.e., the modified F2129, data can be compared against a benchmark test. Tests thus far have revealed two regimes of behavior in regards to corrosion parameters, e.g. corrosion potential. Corrosion test results will be presented as a function of boron content. We have found that low boron content behavior is distinctly different from moderately high boron content results. Breakdown potentials for all of the alloys are quite high, indicating that these alloys are potential candidates for structural implant applications. However, mechanical property considerations will need to be taken into account to further narrow the alloy selection. These issues will also be discussed in light of the current results from our group.