Monitoring and Evaluation of the Corrosion Behavior in Seawater of the Low-Alloy Steels BVDH36 and LRAH36.

The purpose of this study is to evaluate the corrosion resistance in natural seawater (Navodari area) of two types of low-alloy carbon steels BVDH36 and LRAH36 by electrochemical methods. The electrochemical methods used were the evolution of the free potential (OCP), electrochemical impedance spectroscopy (EIS), polarization resistance (Rp) and corrosion rate (Vcorr), potentiodynamic polarization (PD), and cyclic voltammetry (CV). The studies were completed by ex situ characterization analyzes of the studied surfaces before and after corrosion such as: optical microscopy, scanning electron microscopy and X-ray diffraction analysis. The results of the study show us that the polarization resistance of the low-alloy carbon steel BVDH36 is higher compared to the polarization resistance of the low-alloy carbon steel LRAH36. It is also observed that with the increase in the immersion time of the samples in natural seawater, the polarization resistance of the BVDH36 alloy increases over time and finally decreases, and for the carbon steel LRAH36 the polarization resistance increases.

Susceptibility of 316L Stainless Steel Structures to Corrosion Degradation in Salivary Solutions in the Presence of Lactic Acid.

In the field of healthcare and dentistry, 316L stainless steel is widely used for its corrosion resistance. However, the presence of lactic acid in salivary solutions can affect its surface reactivity. This study employed electrochemical methods to investigate the influence of lactic acid on 316L stainless steel's corrosion resistance in Fusayama Meyer saliva and saliva doped with varying lactic acid concentrations. The results revealed a significant decrease in polarization resistance as the lactic acid concentration increased, despite a shift toward more positive corrosion potentials. Consequently, the study suggests that the lactic acid presence in salivary solutions should be considered when evaluating the corrosion susceptibility of 316L stainless steel devices.

Preclinical EIS Study of the Inflammatory Response Evolution of Pure Titanium Implant in Hank's Biological Solution.

Pure titanium (Ti) is investigated in a pre-clinical study in Hank's biological solution using electrochemical methods, open circuit potential, and electrochemical impedance spectroscopy to highlight the time effect in extreme body conditions, such as inflammatory diseases, on degradability due to corrosion processes occurring on the titanium implant. Electrochemical impedance spectroscopy (EIS) data are presented as Nyquist and Bode plots. The results show the increasing reactivity of titanium implants in the presence of hydrogen peroxide, which is an oxygen-reactive compound that describes inflammatory conditions. The polarization resistance, which results from electrochemical impedance spectroscopy measurements, declined dramatically from the highest value registered in Hank's solution to smaller values registered in all solutions when different concentrations of hydrogen peroxide were tested. The EIS analysis provided insights into titanium's in vitro corrosion behavior as an implanted biomaterial, which could not be solely obtained through potentiodynamic polarization testing.

Effect of Functional Nanoporous TiO2 Film Obtained on Ti6Al4V Implant Alloy to Improve Resistance in Biological Solution for Inflammatory Conditions.

The metallic titanium-based biomaterials are sensitive to corrosion-induced degradation in biological fluids in the presence of inflammatory conditions containing reactive oxygen species (ROS). Excess ROS induces oxidative modification of cellular macromolecules, inhibits protein function, and promotes cell death. In addition, ROS could promote implant degradation by accelerating the corrosive attack of biological fluids. The functional nanoporous titanium oxide film is obtained on titanium alloy to study the effect on implant reactivity in biological fluid with reactive oxygen species such as hydrogen peroxide, which are present in inflammations. The TiO2 nanoporous film is obtained by electrochemical oxidation at high potential. The untreated Ti6Al4V implant alloy and nanoporous titanium oxide film are comparatively evaluated for corrosion resistance in biological solution by Hank's and Hank's doped with hydrogen peroxide by electrochemical methods. The results showed that the presence of the anodic layer significantly improved the resistance of the titanium alloy to corrosion-induced degradation in biological solutions under inflammatory conditions.

Enhancement of Corrosion Resistance Properties of Electrodeposited Ni/nano-TiC Composite Layers.

This paper presents novel results on the effects of the dispersion of titanium carbide nanoparticles (50 nm mean diameter) into a nickel-plating electrolyte on the corrosion behavior of the nanocomposite layers obtained. The Ni/nano-TiC layers are compared with pure nickel layers obtained at the same electrodeposition parameters with 60 mA·cm-2 current density and 10 min deposition time. The comparative corrosion performances are investigated using a three-electrode electrochemical cell in a solution (mixed boric acid with lithium hydroxide), which simulates the primary water circuit of pressurized water reactors (PWRs). Open circuit potential measurement and electrochemical impedance spectroscopy were employed as the electrochemical methods, using an electrochemical workstation connected to an electrochemical cell, as well as a PC with software to drive the experimental work. The results clearly revealed enhanced corrosion properties for the Ni/nano-TiC hybrid layers as compared to the pure Ni layers. The significantly improved corrosion behavior can be attributed to the TiC nanoparticles embedded into the Ni matrix, which have the effect of insulating centers at the composite layer/corrosive solution interface.

Reactivity and Corrosion Behaviors of Ti6Al4V Alloy Implant Biomaterial under Metabolic Perturbation Conditions in Physiological Solutions.

The corrosion of implant biomaterials is a well-known critical issue when they are in contact with biological fluids. Therefore, the reactivity of Ti6Al4V implant biomaterials is monitored during immersion in a Hanks' physiological solution without and with added metabolic compounds, such as lactic acid, hydrogen peroxide, and a mixture of the two. Electrochemical characterization is done by measuring the open circuit potential and electrochemical impedance spectroscopy performed at different intervals of time. Electrochemical results were completed by morphological and compositional analyses as well as X-ray diffraction before and after immersion in these solutions. The results indicate a strong effect from the inflammatory product and the synergistic effect of the metabolic lactic acid and hydrogen peroxide inflammatory compound on the reactivity and corrosion resistance of an implant titanium alloy.

Effects of TiO2 Nanoparticles on the Corrosion Protection Ability of Polymeric Primer Coating System.

This research work presents the results obtained from a comparative corrosion evaluation of welded joints on uncoated steel in flat position, welded joints in flat position on steel protected with polymeric film, and welded joints in flat position on steel covered with nanocomposite polymeric film (primer reinforced with TiO2 nanoparticles). The electrochemical methods of open circuit potential, linear polarization resistance, and electrochemical impedance spectroscopy were used for corrosion evaluation. The results of the electrochemical tests indicate that titanium oxide reinforcing polymeric film to form nanocomposite layers over naval welded steel increases the corrosion protection of polymeric film as compared with unmodified primer.

Electro-codeposition of CeO2 nanoparticles into cobalt matrix to improve the tribocorrosion performances of Co/nano CeO2 composite layers in biological solution for medical applications.

Co/nano-CeO2 composite layers were developed by electro-codeposition method from a cobalt electrolyte containing dispersed CeO2 nanoparticles. The tribocorrosion performances of both Co/nano-CeO2 and pure Co layers were comparatively investigated by sliding friction tests under lubricated condition in biological Hank solution. The effect of embedded nano-CeO2 on the corrosion electrochemical response, friction coefficient and wear loss volume is analyzed. The results show that the codeposited of nano-CeO2 particles into cobalt matrix reduce the friction coefficient and wear weight loss as well as the shift of open circuit potential to active state, increasing the polarization resistance and reducing the corrosion damages.

Anticorrosion Performance of the Electrochemically Grown Mixed Porous Oxide Films on Titanium Alloy in Biological Solution.

A thin porous mixed layer of TiO2-ZrO2 was grown on titanium-zirconium alloy surface by electrochemical oxidation. Further comparison of the corrosion behavior in Fusayama-Meyer biological solution was performed. Scanning electron microscopy surface morphology investigations confirm the presence of porous oxide film, while energy-dispersive X-ray spectroscopy analyses provide a high amount of oxygen element in the porous film and a higher amount of Zr element, concluding the mixed nature of oxide film formed, TiO2-ZrO2. For corrosion investigations, electrochemical techniques such as open-circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization were applied. The corrosion investigations reveal better behavior of the thin porous mixed oxide layer on titanium alloy compared to the untreated alloy having on their surface the native oxide formed in contact with the air, confirming the possibility to improve the properties of such implant application in saliva solution.

Enhancement in sustained friction and wear resistance of nanoporous aluminum oxide films obtained by controlled electrochemical oxidation process.

The primary purpose of this study is to investigate the effect of the electrochemical parameters required in the anodic oxidation process on the friction and wear resistance of the obtained nanoporous aluminum oxide films. The wear resistance of the aluminum oxide films and the electrochemically polished Al1050 alloy were tested using a ball-on-disc tribometer having a corundum ball as counterbody in dry conditions. The friction coefficient graphs were recorded during wear tests at a 5 N normal force simulating the application of nanoporous aluminum oxide films in industrial areas requesting moderate wear resistance. The wear tracks formed on the tested surfaces were analyzed ex situ both qualitatively and quantitatively. Higher wear resistance is showed by nanoporous aluminum oxide films as compared with electro polished Al1050 alloy substrate.

Effect of Nano-TiC Dispersed Particles and Electro-Codeposition Parameters on Morphology and Structure of Hybrid Ni/TiC Nanocomposite Layers.

This research work describes the effect of dispersed titanium carbide (TiC) nanoparticles into nickel plating bath on Ni/TiC nanostructured composite layers obtained by electro-codeposition. The surface morphology of Ni/TiC nanostructured composite layers was characterized by scanning electron microscopy (SEM). The composition of coatings and the incorporation percentage of TiC nanoparticles into Ni matrix were studied and estimated by using energy dispersive X-ray analysis (EDX). X-ray diffractometer (XRD) has been applied in order to investigate the phase structure as well as the corresponding relative texture coefficients of the composite layers. The results show that the concentration of nano-TiC particles added in the nickel electrolyte affects the inclusion percentage of TiC into Ni/TiC nano strucured layers, as well as the corresponding morphology, relative texture coefficients and thickness indicating an increasing tendency with the increasing concentration of nano-TiC concentration. By increasing the amount of TiC nanoparticles in the electrolyte, their incorporation into nickel matrix also increases. The hybrid Ni/nano-TiC composite layers obtained revealed a higher roughness and higher hardness; therefore, these layers are promising superhydrophobic surfaces for special application and could be more resistant to wear than the pure Ni layers.