Investigation of Hafnium for Biomedical Applications: Corrosion and Tribocorrosion in Simulated Body Fluids
Metals have excellent properties, such as high strength, ductility and toughness, which make them the material of choice for many biomedical applications. However, the main drawback of metals is their general tendency to corrode, which is an important factor when they are used as biomaterials due to the corrosive nature of the human body.
Titanium and titanium alloys are widely used in biomedical devices due to their excellent corrosion resistance and good biocompatibility. However, one of the disadvantages of titanium is its low wear resistance.
Hafnium is a passive metal with a number of interesting properties, such as high ductility and strength, as well as resistance to corrosion and mechanical damage. Previous studies have shown that hafnium has good biocompatibility and osteogenesis. However, the behaviour of hafnium in biological environment has not been studied in great depth. Furthermore, little is known about the resistance of the passive layer under wear-corrosion conditions and the effect of proteins on its corrosion and tribocorrosion behaviour.
The overall goal of this study is to assess the potential of hafnium for use in biomedical applications. The aim of this work is to investigate the corrosion resistance of hafnium in simulated body fluids as well as its behaviour in wear corrosion and fretting corrosion conditions.
The results showed that hafnium presents a passive state in the presence of proteins and its oxide layer provides high protection to corrosion. In addition, although the passive layer could be disrupted due to wear and fretting, increasing the corrosion of the metal, it was rapidly rebuilt when the damaging ceased. On the other hand, the main drawback of hafnium was its tendency to suffer from localised corrosion. Although the formation of corrosion pits was retarded in the presence of proteins, it was drastically increased when hafnium was scratched or subjected to fretting.