Corrosion Penetration Rate Research Articles

Substantial effect of magnesium incorporation on hydroxyapatite/carbon nanotubes coatings on metallic implant surfaces for better anticorrosive protection and antibacterial ability

This work elucidates the antibacterial and corrosion protection efficiency of Mg substituted hydroxyapatite/multiwalled carbon nanotube composite coated 316L SS implant. A novel spray deposition method was adopted for the composite coating. The fabricated HA/MWCNT and Mg-HA/MWCNT films were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and Field emission scanning electron microscopy. Mg addition played a significant role to decrease the crystallinity and increase the surface area of the HA/MWCNT composite. The vibrational spectra show shift in the PO stretching vibration of PO43− group at 1127 cm-1 after Mg substitution. The morphology of Mg-HA/MWCNT coating revealed spherical shaped apatite crystals with interconnected network like microstructure which is beneficial for bone tissue engineering. The Mg-HA/MWCNT nanocomposite revealed a better antibacterial activity against E.coli with a high zone of inhibition of 16 mm. The electrochemical behaviour of the Mg-HA/MWCNT/SS in simulated body fluid demonstrated an increased polarization resistance with decreased current density (icorr). Compared to bare HA/CNT coated implant, the Mg ions substituted implant revealed superior corrosion resistance with a lower corrosion penetration rate. Thus, the bioactive Mg-HA/MWCNT composite coated 316L SS implant developed with superior antibacterial and anticorrosion properties is considered as the potential aspirant for orthopaedic applications.

Modelling and Optimization of Corrosion Penetration Rate (CPR) for Crude Oil Transportation Processes by Pipeline

Modelling and Optimization of Corrosion Penetration Rate (CPR) for Crude Oil Transportation Processes by Pipeline

Corrosion behaviour of AA6082 Al-Mg-Si alloy extrusion: Recrystallized and non-recrystallized structures

In the present study, the corrosion behaviour of AA6082 Al-Mg-Si alloy extrusion, consisting of a recrystallized surface region and non-recrystallized fibre structure core, is investigated. It is found that the corrosion penetration rate and propagation path are closely related to grain structure and local plastic deformation. Corrosion morphology changes from intergranular corrosion in recrystallized region to both intergranular and intragranular corrosion of the heavily deformed subgrains in non-recrystallized region. Further, local plastic deformation is quantified by electron backscatter diffraction and transmission Kikuchi diffraction and correlated to corrosion propagation path.

An experimental study of electrochemical incompatibility between repaired patch concrete and existing old concrete

This research program examines the performance of different patch repair strategies for repairing concrete bridge deck slabs, damaged due to premature corrosion of embedded reinforcing steel bars (rebars). The electrochemical compatibility between the repaired patch concrete and the existing old concrete in fifteen (1000 mm × 1000 mm × 200 mm) specimens was examined using half-cell potential, chloride content, rebar mass loss and corrosion penetration rate tests. The experimental results showed that the potential difference between the repaired patch concrete and the existing old concrete local corrosion increased significantly at the periphery of the patch, and gradually progressed into the repaired zone. This effect varied from one repair technique to another. Different measures to increase the service life of the repair system are also proposed, such as incorporating a sacrificial embedded anode, an impressed current cathodic protection system, along with the use of surface coating or membrane as an additional line of defence.

Corrosion of Sn-Zn-Bi Lead Free Solder in KOH Electrolyte

The corrosion of Sn-Zn-Bi lead free solder in 6M KOH electrolyte was conducted. The study was done using 3 different KOH concentrations (3M, 6M and 9M) and the immersion technique was used to produce corrosion. Due to the nature of immersion, the solder material was prepared by punching it into small billets size after melting it homogenously on a commercial hotplate. The immersion was set to 7, 14 and 21 days. After the specific days have fulfilled the sample billets were removed and tested. The corrosion of this solder was measured using various method such as graphical analysis, surface roughness, corrosion penetration rate (CPR) and optical microscope. In this research, it was found out that the sample billets taken from 6M concentration compared to 3M and 9M showed more corrosion this was supported by the outcome of the test. The 6M believed to provide best corrosion on the solder billets because of its high ionic conductivity value.

Effect of Nano-Ceria on Physiognomies of Aluminum-5% Zinc Sacrificial Anode

Sacrificial anodes possessing higher electrochemical efficiency is the demand of marine, oil and gas industries. Due to high energy capability and long life light weight aluminum based anodes are more favorable as compare to magnesium and zinc based anodes to protect the engineering structures from corrosion. In present study an attempt was made to develop Al-5% Zn based composite with nano-ceria. The effect of nano-ceria on physiognomies of Al-5% Zn anode was determined through weight loss, CPR (Corrosion Penetration Rate) and emf study in CCP (Close Circuit Potential) conditions. The results indicated that by incorporating the ceria in the matrix of Al-5% Zn anode the corrosion inhibition efficiency and hardness were increased significantly.

Amorphous Metallic Alloys: Pathways for Enhanced Wear and Corrosion Resistance

Amorphous metallic alloys are widely used in bulk form and as coatings for their desirable corrosion and wear behavior. Nevertheless, the effects of heat treatment and thermal cycling on these surface properties are not well understood. In this study, the corrosion and wear behavior of two Zr-based bulk metallic glasses were evaluated in as-cast and thermally relaxed states. Significant improvement in wear rate, friction coefficient, and corrosion penetration rate was seen for both alloys after thermal relaxation. A fully amorphous structure was retained with thermal relaxation below the glass transition. There was an increase in surface hardness and elastic modulus for both alloys after relaxation. The improvement in surface properties was explained based on annihilation of free volume.

Fabrication of silver- and strontium-doped hydroxyapatite/TiO2 nanotube bilayer coatings for enhancing bactericidal effect and osteoinductivity

Hydroxyapatite (HA)-coated implants are more susceptible to bacterial infection because their bioactive surface, which is favourable for osseointegration, could also become a reservoir for bacterial colonisation. To solve this problem, an electrodeposition method for preparing silver- and strontium-modified antibacterial HA layers onto TiO2 nanotubes (TNs) was developed. Ag was incorporated into the HA coating to improve its antimicrobial properties. Sr was added as a second binary element to offset the potential cytotoxicity of Ag. Results showed that Sr2+ and Ag+ could be evenly incorporated into the HA lattice to form SrAgHA coatings. The TN layer with a diameter of 100nm strengthens the adhesion via the anchoring effect. In vitro electrochemical corrosion studies demonstrated that the SrAgHA/TN coating sustains the stimulated body-fluid (SBF), thus indicating excellent corrosion resistance with a lower corrosion penetration rate than the bare commercially pure (CP)-Ti substrate. The composite coatings were found to be bioactive, based on the promotion of additional apatite onto the SrAgHA coating surface from SBF. Staphylococcus aureus growth was inhibited by SrAgHA/TN coatings, whereas the coatings without Ag had no effect on bacterial growth. MC3T3-E1 cell culture revealed that SrAgHA/TN demonstrated better cytocompatibility, and permitted stimulated cell proliferation, attachment and differentiation capacities than uncoated CP-Ti substrate. The addition of Sr to the AgHA coatings effectively counteracted the potentially negative effects and improved the performance compared with CP-Ti. The improved antibacterial effects, correlated with superior cytocompatibility and mechanical behaviour, suggested that SrAgHA/TN can be an alternative to pure HA for the preparation of reliable implant coatings for orthopaedic applications.

The Corrosion Performance of Al-Si and Al-Cu Casting Alloys in H 2 SO 4 and Na 2 CO 3 Media

This paper focuses on corrosion performance of aluminium-silicon (Al-Si 7 %) and aluminium-copper (Al-Cu 15 %) alloys, produced locally by a casting process, under different conditions of media and temperatures. The selected media are acidic (10 % H2SO4solution) and alkaline (10 % Na2CO3 solution). The corrosion experiments used weight loss and corrosion penetration rate within interval immersion periods of 5 hours. The surface morphology was studied using optical and scanning electron microscopes (SEM). It was observed that, Al-Si 7 % alloy shows less of weight loss and higher corrosion resistance in 10 % H2SO4 and 10 % Na2CO3solutions rather than Al-Cu 15 % alloy at room temperature. The corrosion clearly increased and the attack was more significant at 50 °C. Moreover, corrosion rate values of Al-Si and Al-Cu alloys are higher in H2SO4medium, due to the hydrogen enhancement for the cathodic reaction, than in alkaline medium. This result relates to the formation of Al-Si and Al-Cu oxide surfaces. On the other hand, the surface morphology of the Al-Cu alloy shows that there are clear colored SO42− and CO32− precipitates formed after 5 hours immersion, whereas this behavior does not appear on the Al-Si alloy surface. SEM images show that the corrosion performance increased mainly in the acid medium rather than the alkaline one in which the pores produced on the Al-Si surface may contribute to a decline of sites in the oxide surface.

Strontium and copper co-substituted hydroxyapatite-based coatings with improved antibacterial activity and cytocompatibility fabricated by electrodeposition

Bacterial infection are serious complications for biomedical implants in the orthopedic and dental fields, and the ideal implants should combine good antibacterial ability and bioactivity. In this paper, we have fabricated the strontium/copper substituted hydroxyapatite (SrCuHA) coating on the commercially pure titanium (CP-Ti) and studied their effect on antibacterial and in vitro cytocompatible properties. Cu was incorporated into HA in order to improve its antimicrobial properties. Sr was added as a second binary element to improve the biocompatibility. The structural and morphological characteristics of the SrCuHA coatings were investigated using various analytical techniques. The presence of Sr2+ and Cu2+ in solution led to reduced roughness of the coating and finer nucleus size formed. The results highlight that Sr2+ and Cu2+ were homogenously incorporated into HA lattice to form SrCuHA coatings. Inductively coupled plasma mass spectrometry (ICP-MS) was used for the leach out analysis of the samples. A low contact angle value revealed the hydrophilic nature. In vitro electrochemical corrosion studies indicated that the SrCuHA coating sustain in the stimulated body-fluid (SBF), exhibiting superior corrosion resistance with a lower corrosion penetration rate than the bare CP-Ti substrate. The SrCuHA coatings can kill Escherichia coli to a certain extent during the first few days, which might be due to the Cu substitution in the coating. An enhancement of in vitro osteoblast adhesion, proliferation, and alkaline phosphatase activity was observed, which could lead to the optimistic orthopedic and dental applications.

Apatite layer growth on glassy Zr48Cu36Al8Ag8 sputtered titanium for potential biomedical applications

The bioactivity of magnetron sputtered thin film metallic glasses (TFMGs) of Zr48Cu36Al8Ag8 (at.%) on titanium substrates was tested for bio implant applications. The structural and elemental compositions of TFMGs were analyzed by XRD, XPS and EDAX. X-ray diffraction analysis displayed a broad hump around the incident angle of 30–50°, suggesting that the coatings possess a glassy structure. An in situ crystal growth of hydroxyapatite was observed by soaking the sputtered specimen in simulated body fluid (SBF). The nucleation and growth of a calcium phosphate (Ca–P) bone-like hydroxyapatite on Zr48Cu36Al8Ag8 (at.%) TFMG from SBF was investigated by using XRD, AFM and SEM. The presence of calcium and phosphorus elements was confirmed by EDAX and XPS. In vitro electrochemical corrosion studies indicated that the Zr-based TFMG coating sustain in the stimulated body-fluid (SBF), exhibiting superior corrosion resistance with a lower corrosion penetration rate and electrochemical stability than the bare crystalline titanium substrate.

Modelling the Corrosion Rate of Buried Pipes Using Modified Artificial Neural Network (MANN) Coupled with Monte Carlo Simulation

Several researchers have developed models to predict corrosion rate in buried structures with good results using methods such as artificial neural networks, Monte Carlo to mention a few. This paper presents a novel approach to predicting corrosion rate in buried structures using Monte Carlo and a modified artificial neural network (MANN). Monte Carlo Simulation is used in this paper to estimate the probability of occurrence of uniform corrosion in buried steel pipes in different soil locations using the fixed walk method. The central limit theory and law of large numbers were utilised to reduce errors. While Modified Artificial Neural Networks was used to establish the relationships. Data used for this study were obtained from weight loss study of Nickel electroplated and non electroplatedAISI-1051 samples. The parameters measured were soil pH, soil temperature and atmospheric temperature of different soils taken from an oil producing site in Delta State, Nigeria. These parameters were assumed normally distributed. Corrosion Penetration Rate (CPR) was calculated for each scenario using the weight loss method. Relating these input Original Research Article Nosa and Bolaji; ACRI, 4(2): 1-8, 2016; Article no. ACRI.25564 2 parameters to the calculated CPR was possible via the employment of Modified Artificial Neural Networks, which makes use of the least square polynomial regression equations instead of the neuron box to avoid complexities in neuron number determination. Weights and Scaling factors were set appropriately to allow for easy convergence. Third degree polynomial equations were derived from the MANN and used as inputs for the MCS. Results from the MCS showed 80% correlation with data used and a reliable estimate for the CPR was achieved using this MCSMANN approach. The CPR of the Nickel Electroplated Sample was less than zero which was in good agreement with the weight loss data. It is observed that the CPR values for Non-electroplated samples were 60% of the time higher than the values for electroplated samples.

Corrosion Behavior of Aluminum-Silicon-Copper-Manganese Alloy in Sulfuric Acid Medium

The present paper discussed the corrosion behavior of aluminum-silicon-copper-manganese alloy compared with the pure aluminum metal which already reported. Weight loss tests carried out in concentration ratios of H 2SO4 solutions at different temperatures. As a part of the study, corrosion penetration rate determined within interval immersion periods of 5 h. At room temperature, it is observed that aluminum alloys shows decreasing of weight loss and more corrosion resistance in concentrations 10 and 15 % of H 2SO4 solutions compared with the obtained results of pure Al metal. Moreover, corrosion rate increases slightly with increasing concentration of H 2SO4media and the attack is more significant at 50 ∘C. Also, the corrosion penetration rate of Al alloy decreased in the same trend as a result of the formation of thin protective multi oxide films of aluminum, silicon, copper and manganese. Furthermore, the microscopic analysis showed that there is fine pits appeared on the Al alloy surface correlated directly with the increased exposure period in the acidic solution whereas in case of pure Al metal there were a many horizontal streaks formed along the surface.

Effect of Adenine Concentration on the Corrosion Inhibition of Aisi 304l Steel in 1.0m Sulphuric Acid Solution

Over the years considerable efforts have been deployed to finding suitable (safe and friendly) corrosion inhibitors of organic origin in the various aggressive acid media encountered in service especially during the processes of pickling, industrial acid cleaning, acid descaling and oil well acidizing. In this research the effect of adenine concentration on the corrosion inhibition of AISI 304L in 1.0 M sulphuric acid solution has been investigated. The research was achieved by using 1M concentration of acid solution and varied inhibitor concentration. Readings were obtained every 240hours (10 days) for a period of 1200hours (50 days). Weight loss, corrosion penetration rate, inhibition efficiency and degree of surface coverage were calculated. Results obtained revealed that adenine is an effective and safe corrosion inhibitor for AISI 304L in 1.0M sulphuric acid solutions. Analysis of the results showed that the inhibition efficiency and surface coverage increases with increasing adenine concentration till a certain maximum value, causing a decrease in corrosion penetration rate and weight loss. A maximum value of inhibition efficiency of 89.56% was achieved at 0.011M adenine concentration after 10 days. This gave a surface coverage of 0.8956 and corrosion penetration rate of 0.022132mm/yr. Hence, the best adenine concentration for the corrosion inhibition of alloys 304L in 1.0M sulphuric acid solution to obtain optimum inhibition efficiency is 0.011M. Keywords: Corrosion, AISI 304L Steel, Inhibition efficiency, Degree of Surface coverage, 1.0M Sulphuric Acid Solution

Corrosion Rate of Sand Blasted and Acid Etched Ti6Al4V for Dental Implants

The aim of present research was to find an effective method to manufacture sand blasted and acid etched (SLA) Ti6Al4 V surfaces for dental implants, with an average surface roughness Ra of 1...2 μm and a proper surface topography, as the morphology of dental implant surface is of extreme importance in the process of implant osseointegration. Several disc samples were subjected to sand blasting with 250...300 μm SiO2 large grits followed by different procedures of acid etching using sulfuric acid and hydrochloric acid (single acid baths, dual acid bath), at room temperature and elevated temperature (60°). Corrosion rate and corrosion penetration rate were calculated from weight loss. The Ra roughness of samples was measured in each stage of the process. Scanning electron microscopy was performed in order to characterize the topography of the surfaces. We found that a proper SLA surface, with a roughness Ra of 2 μm, and a topography with micropits less than 10 μm, can be obtain by sand blasting the machined surface with large grits and then acid etching it using a mixture of (H2SO4+HCl) (1:1) at 60 °C, for 24 hours.

Anti-corrosion behaviour of VE/GF coatings on mild steel

Abstract In this study, the properties of vinyl ester/glass flake (VE/GF) coating on mild steel plates was investigated to determine its anti-corrosion performance. The corrosion penetration rate of VE/GF coated and uncoated mild steel was evaluated using immersion tests for 20 days. Corrosion resistance of the coating was evaluated in various corrosive environments viz. 5% HCl, 8% HCl, 5% NaOH and 7% NaOH. The mild steel plates were coated with four different thicknesses of VE/GF coating and a comparative analysis was carried out to evaluate the corrosion protection efficiency. Scanning electron microscopy was carried out before and after the immersion test to study the morphological changes and products of corrosion.

Evaluation of Corrosion Behaviour for Aluminium Alloy 7075 in 5% NaCl Solution under Slightly Varying Temperature

The main focus of this work is to study and evaluate the corrosion behavior of aluminium alloy 7075 under slightly varying temperature conditions. The corrosion behavior was found out using the Salt Mist test. Aluminium alloy 7075 possesses better corrosion resistance, so it is important to foresee the corrosion behavior of this alloy for varied applications. The Corrosion Penetration Rate was evaluated for the small temperature changes and the results show that the penetration rate increases as temperature increases gradually along with the time for which the specimens are tested. The final result is that aluminium alloy 7075 follows logarithmic law of corrosion at low temperatures.

Rates ofin vivo(arterial) andin vitrobiocorrosion for pure magnesium

The development of magnesium-based materials for bioabsorbable stents relies heavily on corrosion testing by immersion in pseudophysiological solutions, where magnesium degrades faster than it does in vivo. The quantitative difference in corrosion kinetics in vitro and in vivo is largely unknown, but, if determined, would help reduce dependence on animal models. In order to create a quantitative in vitro-in vivo correlation based on an accepted measure of corrosion (penetration rate), commercially pure magnesium wires were corroded in vivo in the abdominal aortas of rats for 5-32 days, and in vitro for up to 14 days using Dulbecco's modified eagle medium. Cross-sectioning, scanning electron microscopy, image analysis, a modified penetration rate tailored to degraded wires, and empirical modeling were used to analyze the corroded specimens. In vitro penetration rates were consistently higher than comparable in vivo rates by a factor of 1.2-1.9× (±0.2×). For a sample <20% corroded, an approximate in vitro-in vivo multiplier of 1.3 ± 0.2× was applied, whereas a multiplier of 1.8 ± 0.2× became appropriate when the magnesium specimen was 25-35% degraded.

&amp;lt;i&amp;gt;Amaranthus cordatus&amp;lt;/i&amp;gt; as a Green Corrosion Inhibitor for Mild Steel in H&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;SO&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; and NaCl

This work studies the use of Amaranthus cordatus as the corrosion inhibitor for conventional mild steel in 0.5 M and 1.0 M of both H2SO4 and NaCl. The effects of different concentrations of the acid and base on the inhibition efficiency of Amaranthus cordatus were tested at room temperature and at different inhibitor volumes. The experiment was set for 30 days and weight-loss corrosion technique was employed in obtaining the corrosion penetration rate using the standard equation: . The result shows that the rates of corrosion of the mild steel increased with an increase in concentration of the acid or base and also decreased with increasing volume of Amaranthus cordatus. Expectedly, the inhibition efficiency was found to be greater in sodium chloride than in tetraoxosulphate VI acid. Also inhibition efficiency was found to increase with increase in extracts volume and decrease in concentration of the acid or base. These findings strongly suggest that Amaranthus cordatus can be used as the inhibitor for preventing the corrosion of mild steel.

Assessment of fatigue and corrosion fatigue behaviours of the nitrogen ion implanted CpTi

The fatigue and corrosion fatigue behaviours of commercially pure titanium (CpTi) have been particularly studied because the requirements of titanium (Ti) base materials are widely used for biomedical applications. The optimal properties of CpTi surface can be preserved by nitrogen ion implantation at a certain dose and energy. Still the fatigue and corrosion fatigue behaviours of nitrogen ion implanted CpTi (Nii-Ti) must be verified. This study performs the fatigue tests for CpTi and Nii-Ti specimens in a laboratory air and the corrosion fatigue tests for Nii-Ti specimens in a saline solution. Effects of nitrogen ion implantation on surface properties can improve the fatigue strength, fatigue life and corrosion fatigue life of Ti base materials. The corrosion pit growth law has been established on the basis of empirical data for predicting the corrosion penetration rate to estimate to the service life of Nii-Ti.