Tribocorrosion and microhardness study of powder metallurgy titanium alloys
The main aim of the stay at the Functionalized Materials and Surfaces Performance Group of the University of Minho is to study the tribocorrosion behavior of different surfaces of titanium for biomedical applications and their microhardness.
The samples are processed at the Powder Technology Group (GTP) of the University Carlos III of Madrid. These titanium samples are surface modified with different elements and by varied treatments. The idea is to increase the wear resistance of the surface while maintaining or increasing the corrosion resistance.
Tribocorrosion and microhardness studies are made in samples which consist of the substrate plus a coating. There are four different groups of substrates: (1) Green Titanium (as pressed, before sintering), (2) Sintered Titanium, (3) Green Ti6Al4V and (4) Sintered Ti6Al4V. Green substrates are prepared by uniaxial pressing, and the sintered ones by uniaxial pressing and vacuum sintering. The substrates are covered by five different coatings: (1) Molybdenum, (2) Activated molybdenum by ammonium chloride, (3) Titanium Nitride, (4) Molybdenum-Titanium Nitride and (5) Niobium.
With the aim of obtaining a better knowledge of the fabricated titanium alloys: tribocorrosion tests are performed in the surface of the sample to study the effect of wear and corrosion simultaneously, and microhardness tests are carried out in the cross section of the samples in order to get a hardness profile; evaluating the hardness from surface to inward.