Surface performances of Ti-6Al-4V substrates coated PVD multilayered films in biological environments

Multilayered and nanostructured coatings of Ti based alloys (oxides and nitrides) are elaborated and tested for increasing protective properties such as corrosion and wear resistances. A pin-on-disc tribometer was used to evaluate the wear resistance in Hank's solution against bovine bone. Corrosion behavior in Hank's solution was determined by potentiodynamic and electrochemical impedance spectroscopy techniques. Besides, the specimen surfaces were characterized by Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) microanalyses. The results showed that optimal tribological properties were obtained in the case of coatings having TiN as top layer. The main wear mechanism was abrasive third body wear. In vitro corrosion tests at 37 °C showed that the better corrosion resistance was obtained when TiN was the top layer. However all of them exhibited good tribological properties, good corrosion resistance and then may be promising options for biomedical applications

Influence of Vanadium on the Corrosion Behavior of High Manganese Steel in 0.5 M H₂SO₄ Solution

The effect of vanadium on the corrosion behavior of high manganese steel in 0.5 M H₂SO₄ solution has been investigated using scanning electron microscopy, potentiodynamic polarization and impedance spectroscopy. The results have shown that the addition of vanadium to high manganese steel decreases the corrosion current density from 2.1 mA cm¯² to 1.29 mA cm¯². Impedance diagrams show the existence of a high frequency capacitive loop and a low frequency inductive loop. The addition of vanadium increases charge transfer resistance from 5.18 Ω cm² to 12.45 Ω cm²

Reliability of the High Strength Pipeline Steel under Corrosion Defect

The demand of energy based on hydrocarbons, such as gas and oil, requires construction of more and more new pipelines. Therefore, the assessment of the remaining life of these pipeline structures became increasingly important to ensure the continuity of production and distribution operations. The reliability of these industrial facilities is largely conditioned by specific characteristics of each system, by its conditions of use and its environment. Generally, the causes of deterioration of hydrocarbon transportation pipelines are related to the presence of apparent defects (pinholes, cracks, corrosion, etc). This study is aimed to estimate the reliability of pipeline structures. The B31G mechanical model of degradation was used to assess the probability of failure through dimensions of defects