Increasing Immersion Time Research Articles

Weight loss and electrochemical measurements of aluminum corrosion in diesel fuel and biodiesel prepared via transesterification of waste cooking oil

Recent studies have found potentials in the utilization of biodiesel from renewable energy sources to tackle environmental pollution associated with the release of exhausts from fossil diesel fuel engines. However, it's imperative to investigate the corrosion rate and nature of the engine components fuelled with the biodiesel. This study examines the corrosion rate and nature of aluminum coupon (AC) in fossil diesel fuel (DF) and biodiesel produced from waste cooking oil via transesterification reaction (WCOB) using weight loss and electrochemical measurements. Taguchi Orthogonal Array was used to study the influence of temperature, immersion time, agitation and WCOD/DF volume. Weight loss method revealed highest corrosion rates to be 0.0052 mm y−1 and 0.0381 mm y−1 for AC in DF and WCOB respectively. Corrosion rate increased with increase in immersion time and temperature. A shift in the corrosion potential from -0.192 V to -0.574 V; and -0.178 V to -0.516 V was revealed by potentiodynamic polarization curve for AC in WCOB and DF respectively. Nyquist plots exhibited relatively perfect semicircles of different diameters and similar shape. The developed mathematical models were effective for corrosion rate prediction. Minimum corrosion rates of 1.222 × 10−3 mm y−1 and 1.822 × 10−3 mm y−1 for AC in DF and WCOB are respectively feasible at optimum point. Presence of carbon and oxygen on AC surface; pits formation; and loss of Al ion into WCOB and DF after corrosion were noticed. In conclusion, the corrosion rate of AC in WCOB was higher than the DF counterpart.

Evaluation of the Effect of Static and Flowing Conditions on the Corrosion Behavior of the Hull of Marine Ships

Marine ship hulls' corrosion resistance behavior under static and flowing conditions was investigated. The metal of the hull panels of marine ships was chemically and mechanically examined and analyzed, revealing that carbon steel type DIN 1.0501 C35 is employed in constructing the hull of ships in the port of Basrah in Iraq. A corrosion resistance test for this metal was carried out in laboratory-prepared seawater under static and flowing conditions at a flow rate of 1500 liter/hour and various immersion times (12, 24, 48, 120, 168, 336) hours. The temperature was kept constant at 30°C, and a fixed salt concentration of (3.5% sodium chloride). The corrosion rate of C35 carbon steel was calculated using the weight loss method is an effective method for calculating the corrosion rate of carbon steel. The samples were examined using a scanning electron microscope (SEM) for corrosion analysis. Conclusions from this research indicate that an increase in the flow rate resulted in an elevation of the corrosion rate, doubling the corrosion rate compared to samples under static conditions. The corrosion rate exhibited a significant increase during the first 24 hours, followed by a gradual decrease with increasing immersion time. The corrosion rate increased by 682.9%. The speed of corrosion was fast initially, but the weight loss slowed after 24 hours of immersion. A scanning electron microscope (SEM) examination revealed that the flow environment was aggressive for carbon steel. It was much more severe, and the pits and grooves were more significant than the static condition.

Electrochemical noise characterization of corrosion behavior for NiCrAl-NiC coating

The electrochemical noise analysis (including frequency domain and wavelet analyses) method is used to characterize the corrosion behavior of NiCrAl-NiC Abradable Seal Coating (ASC) at different immersion times. By converting EN data to frequency domain analysis, the slope (k values) of current power spectral density (PSD) curves of NiCrAl-NiC ASC increases with prolonged immersion time, suggesting a transition from localized corrosion to pitting. Wavelet analysis results indicate that the D7-D8 detail coefficients control the wavelet energy throughout the immersion process, and with increasing immersion time, the electrochemical activity on the NiCrAl-NiC ASC surface decreases. The electrochemical noise analysis can effectively explain the corrosion behaviors of NiCrAl-NiC ASC.

Preparation, Mechanical Properties, and Degradation Behavior of Zn-1Fe-xSr Alloys for Biomedical Applications.

As biodegradable materials, zinc (Zn) and zinc-based alloys have attracted wide attention owing to their great potential in biomedical applications. However, the poor strength of pure Zn and binary Zn alloys limits their wide application. In this work, a stir casting method was used to prepare the Zn-1Fe-xSr (x = 0.5, 1, 1.5, 2 wt.%) ternary alloys, and the phase composition, microstructure, tensile properties, hardness, and degradation behavior were studied. The results indicated that the SrZn13 phase was generated in the Zn matrix when the Sr element was added, and the grain size of Zn-1Fe-xSr alloy decreased with the increase in Sr content. The ultimate tensile strength (UTS) and Brinell hardness increased with the increase in Sr content. The UTS and hardness of Zn-1Fe-2Sr alloy were 141.65 MPa and 87.69 HBW, which were 55.7% and 58.4% higher than those of Zn-1Fe alloy, respectively. As the Sr content increased, the corrosion current density of Zn-1Fe-xSr alloy increased, and the charge transfer resistance decreased significantly. Zn-1Fe-2Sr alloy had a degradation rate of 0.157 mg·cm-2·d-1, which was 118.1% higher than the degradation rate of Zn-1Fe alloy. Moreover, the degradation rate of Zn-1Fe-xSr alloy decreased significantly with the increase in immersion time.

Investigation of Oxide Layer Development of X6CrNiNb18-10 Stainless Steel Exposed to High-Temperature Water.

The oxide layer development of X6CrNiNb18-10 (AISI 347) during exposure to high-temperature water has been investigated. Stainless steels are known to form a dual oxide layer in corrosive environments. The secondary Fe-rich oxide layer has no significant protective effect. In contrast, the primary Cr-rich oxide layer is known to reach a stabilized state, protecting the base metal from further oxidation. This study's purpose was to determine the development of oxide layer dimensions over exposure time using SEM, TEM and EDX line scans. While a parabolic development of Cr in the protective primary layer and Fe in the secondary layer was observed, the dimensions of the Ni layer remained constant. Ni required the presence of a pronounced Fe-rich secondary layer before being able to reside on the outer secondary layer. With increasing immersion time, the Ni element fraction surpassed the Cr element fraction in the secondary layer. Oxide growth on the secondary layer could be observed. After 480 h, nearly the entire surface was covered by the outer oxide layer. In the metal matrix, no depletion of Cr or Ni could be observed over time; however, an increased presence of Cr and Ni in the primary layer was found at the expense of Fe content. The Nb-stabilized stainless steel was subject to the formation of Niobium pentoxide (Nb2O5), with the quantity and magnitude of element fraction increasing over exposure time.

Evaluating the bio-functionalities of Ti-6Al-7Nb alloy after surface modification using electrical discharge machining

The present work evaluates the influence of surface modification on the bio-functionalities of Ti-6Al-7Nb alloy in terms of apatite formation, metal ion release rate and anti-bacterial activities. The surface modification in the form of change in surface integrity, and increases in the exposed surface area, has been achieved using wire-electrical discharge machining (WEDM) and electrical discharge μ-drilling(EDD). Due to high discharge energies, molten material will deposit on the parent material (recast layer), which increases the surface roughness (parent surface 0.5 μm to 2.34 μm) and hardness (patent material 304VH to 385VH) after subsequent re-solidification and quenching. Surface roughness and hardness near the micro-drilled hole are observed to increase. After surface modification, the apatite formation is increased on Ti-6Al-7Nb alloy with increasing immersion time and the ion released rate was found lowest on the WEDMed surface as compared to micro drilled and polished surface. Field-emission electron scanning microscopy (FESEM) and energy dispersive x-ray spectroscopy (EDAX) observations confirmed the presence of phosphate and calcium ions on the WEDMed surface and nearby the micro-drilled surface. The variation in colour of the simulated body fluid (SBF) after the immersion of WEDMed, EDD, and polished samples indicates the variable effecton pH levels of the SBF solution for three types of samples.The anti-bacterial bioactivity of Ti-6Al-7Nb was found to be better on the WEDMed surface as compared to polished surfaces, which is due to the formation of a rutile-TiO2 layer on WEDMed surface.

True-triaxial strength characteristics of cement stone subjected to sulfuric acid corrosion: An experimental and theoretical study

True triaxial tests were conducted to investigate the effect of sulfuric acid corrosion on the true triaxial strength of cement stone under different acid immersion times, including the common loading path and novel loading path with constant Lode angle. The chemical composition and microstructure of cement stone under different acid immersion times (0, 7, 14, and 28 d) were examined via X-ray diffraction and scanning electron microscopy. As the duration of acid immersion increases, the concentrations of portlandite (Ca(OH)2) and calcium silicate hydrate (C-S-H) within the cement stone exhibit a gradual decline, while the presence of calcium sulfate (CaSO4) progressively rises. The microstructure of the cement stone was primarily affected by two factors: the damaging and strengthening effects of sulfuric acid and CaSO4, respectively. The damaging effects of the acid were dominant for days 0–14 of immersion, with continuous increase in microstructure damage. Subsequently, the strengthening effect of CaSO4 became apparent for days 14–28 of immersion, with continuous improvement in microstructure integrity. Consequently, the strength of cement stone exhibited a diminishing trend during the initial immersion period of 0–14 days, followed by an enhancement in strength from 14 to 28 days of immersion. Furthermore, a three-dimensional strength criterion was proposed by combining the Hoek–Brown and Matsuoka–Nakai criteria. The failure envelope first shrank and then expanded with increasing immersion time, accurately describing the variation in strength in the three-dimensional principal stress space.

Experimental Study on the Physical Properties of Autoclaved Bricks Made from Desert Sand and Their Resistance to Sulfate Attacks

In order to optimize the application of desert sand autoclaved bricks in rural construction in Xinjiang, this study focuses on the research and development of MU15-grade desert sand autoclaved bricks. Experimental investigations were conducted to examine the relationship between the water absorption rate of desert sand autoclaved bricks and the duration of water absorption while analyzing the impact of the water absorption rate on the compressive strength of these bricks. Additionally, experimental research was carried out to evaluate the appearance, compressive strength, and pore structure of autoclaved bricks after sulfate erosion. The results indicate the following. (1) With an increasing immersion time, the water absorption rate of desert sand-based autoclaved bricks initially rises and then declines, reaching approximately 14.74% when immersed for 4 h, which is close to the saturation water absorption rate. (2) The compressive strength of desert sand-based autoclaved bricks gradually decreases with an increasing water absorption rate, reaching its lowest point when saturation is attained, with a strength loss rate of approximately 33.18%. (3) Finally, after sulfate erosion, cracks and detachment appear on the surface of desert sand-based autoclaved bricks, and these cracks extend and propagate with the continuous accumulation of eroded products. Simultaneously, this process leads to an increase in the proportion of harmful pores by 0.96%, thereby causing a deterioration in strength. Through data analysis, a decay curve of the compressive strength erosion coefficient of desert sand-based autoclaved bricks with the number of sulfate erosion cycles was established, with good accuracy. This study provides theoretical references and technical support for the performance characteristics of desert sand-based autoclaved bricks and their application in rural construction in Xinjiang.

Performance of magnesium oxysulfate (MOS) cement prepared by MgCl2·6 H2O replacing MgSO4·7 H2O

Despite the influence of Cl- on the properties of cement-based materials, water containing Cl- is more convenient for manufacturing cement-based materials in special areas such as islands and reef construction, compared to fresh water. However, research on the effects of Cl- on the properties of magnesium oxysulfate (MOS) cement was limited. In this paper, MOS cement was prepared by replacing MgSO4·7 H2O with MgCl2·6 H2O to investigate the effect of Cl- on the evolution of MOS cement properties. The mechanical properties, water resistance, phase composition, and microstructure of MOS cement were analyzed. When the replacement rate of MgSO4·7 H2O with MgCl2·6 H2O reached 5 %, MOS cement achieved its highest compressive strength of 77.5 MPa after curing for 90 days, despite a reduction in flexural strength due to MgO hydration. After immersion in water, the trend of compressive strength change in MOS cement remained insensitive to increasing immersion time. During the curing process, Cl- facilitated the formation of hexagonal Mg(OH)2 by participating in the hydration products formation process of MOS cement. Hexagonal Mg(OH)2 contributed to matrix construction and became connected with the 5Mg(OH)2·MgSO4·7 H2O phase. Additionally, Cl- promoted the formation of the modified 5Mg(OH)2·MgSO4·7 H2O phase, known as Mg-S-O-H-Cl phase. After immersion in water, the Mg-S-O-H-Cl phase displayed stability, showcasing their capacity to maintain compressive strength relative stability despite adverse factors such as ions leaching (including Mg2+, SO42-, and Cl-) and the phase transformation of MgO.

Syzygium polyanthum (Wight) Walp. leaf extract as a sustainable corrosion inhibitor for carbon steel in hydrochloric acidic environment

This study focuses on an investigation of the corrosion inhibition behavior of Syzygium polyanthum (Wight) Walp. leaf extract (SPWE) of carbon steel in 1.0 M hydrochloric acid medium. Electrochemical methods demonstrated a corrosion inhibition efficiency of 94.65 ± 0.94 % when 2000 ppm extract is added to the corrosive solution. Furthermore, surface analysis results indicated that with the absence of an inhibitor, the steel surface suffered severe corrosion, while the corrosion density was slow, and a film was observed on the surface after applying the SPWE into a corrosive environment. The film formed by the chemical and physical adsorption of compounds such as polyphenol, flavonoid, alkaloid, and tannin onto the carbon steel surface has been qualitatively and quantitatively analyzed in this study. Notably, increased immersion time and reaction temperature led to significant desorption of molecules, reflecting characteristic of physical adsorption. However, the corrosion inhibition efficiency of SPWE remained effective, particularly within the temperature range of 25–35 °C. Therefore, this study provides an efficient inhibitor for carbon steel corrosion in 1.0 M hydrochloric acidic environment that could be possibly added to the corrosion inhibitor system.

تثبيط التآكل للصلب المقوى في كلوريد الصوديوم بنسبة 3.5 % باستخدام عقار بنتوكسيفيلين منتهي الصلاحية: دراسة فقدان الكتلة

Corrosion is a major issue affecting the durability and performance of various metallic materials, leading to substantial economic losses and safety hazards. The corrosion of reinforced steel in sodium chloride environment poses a significant concern for various industrial applications. This study aims to investigate the corrosion inhibition properties of expired pentoxifylline drug on reinforced steel in a 3.5% NaCl solution. The mass loss method was utilized to quantify the corrosion rate and assess the efficiency of the expired pentoxifylline drug as a potential corrosion inhibitor. The results indicate that the corrosion rate of steel in the 3.5% NaCl solution decreased significantly in the presence of expired drug. Higher concentrations of expired drugs have shown a greater impact on corrosion inhibition. Investigation of the effects of temperature on corrosion inhibition efficacy. The inhibition efficiency increased with increasing concentrations of the inhibitor and decreased with increasing immersion time. The experimental data were tested according to the Langmuir adsorption isotherm, through which the equilibrium adsorption constant (Kads) was calculated and found to be 4.38 litres mol-1 as the maximum value when immersed for one day. The standard free energy of adsorption (∆G_ads^o) ranged from 45 to 30.5 kJ mol-1. Keywords: Reinforced steel, sodium chloride medium, inhibition, expired drugs, pentoxifylline

Influence of Immersion Time on the Frequency Domain Characteristics of Acoustic Emission Signals in Clayey Mineral Rocks.

The frequency domain characteristics of acoustic emission can reflect issues such as rock structure and stress conditions that are difficult to analyze in time domain parameters. Studying the influence of immersion time on the mechanical properties and acoustic emission frequency domain characteristics of muddy mineral rocks is of great significance for comprehensively analyzing rock changes under water-rock coupling conditions. In this study, uniaxial compression tests and acoustic emission tests were conducted on sandstones containing montmorillonite under dry, saturated, and different immersion time conditions, with a focus on analyzing the effect of immersion time on the dominant frequency of rock acoustic emission. The results indicated that immersion time had varying degrees of influence on compressive strength, the distribution characteristics of dominant acoustic emission frequencies, the frequency range of dominant frequencies, and precursor information of instability failure for sandstones. After initial saturation, the strength of the rock sample decreased from 53.52 MPa in the dry state to 49.51 MPa, and it stabilized after 30 days of immersion. Both dry and initially saturated rock samples exhibited three dominant frequency bands. After different immersion days, a dominant frequency band appeared between 95 kHz and 110 kHz. After 5 days of immersion, the dominant frequency band near 0 kHz gradually disappeared. After 60 days of immersion, the dominant frequency band between 35 kHz and 40 kHz gradually disappeared, and with increasing immersion time, the dominant frequency of the acoustic emission signals increased. During the loading process of dry rock samples, the dominant frequency of acoustic emission signals was mainly concentrated between 0 kHz and 310 kHz, while after saturation, the dominant frequencies were all below 180 kHz. The most significant feature before the rupture of dry rock samples was the frequent occurrence of high frequencies and sudden changes in dominant frequencies. Before rupture, the characteristics of precursor events for initially saturated and immersed samples for 5, 10, and 30 days were the appearance and rapid increase in sudden changes in dominant frequencies, as well as an enlargement of the frequency range of dominant frequencies. After 60 days of immersion, the precursor characteristics of rock sample rupture gradually disappeared, and sudden changes in dominant frequencies frequently occurred at various stages of sample loading, making it difficult to accurately predict the rupture of specimens based on these sudden changes.

Effect of surface roughness on corrosion behavior of AISI 4340 high-strength steel in sodium chloride solutions

In this work, an AISI 4340 high-strength steel alloy was surface machined to have four different grades of roughness (Ra). The impact of changing Ra on the corrosion of the steel alloy in 3.5% NaCl solutions after 40 min and 24 h was performed using various electrochemical techniques. The cyclic polarization experiments showed that an increase in Ra increases the steel corrosion via enhancing the corrosion current of the alloy. The electrochemical impedance plots also indicated that an increase in Ra reduces the corrosion resistance of the alloy by decreasing the diameter of the semicircle obtained by the Nyquist spectra. The change in potentiostatic current vs time measurements, which were obtained at −350 mV (Ag/AgCl), confirmed that pitting attack occurs and its intensity further increases with increasing Ra for all steel samples. An increase in immersion time also reduces the resistance to corrosion due to the iron dissolution from the surface of the steel alloy. After corrosion, the surface was analyzed using a scanning electron microscope and energy dispersive spectroscopy investigations.

Texturally-enhanced 55S0P and 45S10P Bioactive Glass ceramic particles: Sol-gel fabrication, nano-characterization and comprehensive Bio-evaluation for applications in Bone tissue engineering

Bioactive glass ceramics (BGC) play a pivotal role in bone tissue engineering, specifically addressing challenges associated with bone repair and regeneration. In this study, we developed silica-based 55S0P and 45S10P spherical BGC nanoparticles (NPs), without and with P2O5 content, using a modified Stöber sol-gel process with base hydrolysis. The fabricated spherical NPs with pronounced textural features effectively contribute to enhanced surface roughness, a desirable parameter for improved biological activity in physiologically relevant solutions and tissue matrices. A comprehensive evaluation of the structural properties of these novel spherical BGC-NPs using diverse characterization techniques revealed distinct nano-textural features in the form of cracks and pores. The HR-TEM confirmed the nanoscale dimensions (170–190 nm) of particles with spherical surface morphology and also systematically analysed via DLS, FE-SEM studies. An augmented surface area with mesopores when phosphate added to the silica glass network was revealed by BET analysis. On the biological front, the study records the formation of an HCA layer on the surfaces of the BGC-NPs, the thickness of which increased with an increase in both phosphate content and immersion time (0, 3, 14 & 28 days) in the SBF solution. The zeta potential values attain a maximum from −22 mV to −23.6 mV for 55S0P and −21.5 mV to −26.4 mV for 45S10P BGC-NPs, and improved with increased immersion time, thereby favouring cellular adhesion for desired biological responses. In vitro, cell culture studies on MG-63 cells, after 24 and 72 h of incubation, demonstrated higher cell adhesion and proliferation, with pronounced biocompatibility. In addition, these BGC-NPs exhibited good hemocompatibility even at the highest test concentration (15 mg/ml) and demonstrated effective antibacterial activity against K. pneumoniae and E. coli. A combinatorial analysis of structural and biological properties revealed that the 45S10P BGC-NPs are more potent than 55S0P BGC-NPs for desired biological performances. In conclusion, the results suggest that the sol-gel fabricated BGC-NPs with enhanced nano-textural features are evidently suitable for applications in bone tissue engineering and regenerative medicine.

Strength degradation of foamed cement paste under sulfate attack

Foamed cement paste is increasingly being applied in the construction of road embankments, bridge abutments, slope treatments, and pipeline backfilling. Constructed foamed cement paste may suffer from sulfate attacks in certain environments, such as offshore regions and salty soil areas. However, the long-term performance of foamed cement paste under such circumstances remains unclear. In this study, laboratory tests are conducted to evaluate the strength deterioration of foamed cement paste after erosion by sulfate attack. Factors influencing the density of the foamed cement paste, concentration of the sulfate solution, and cation type (i.e., Na+ and Mg2+) are considered. The results indicate that the strength of the foamed cement paste decreases with increasing immersion time. The Na2SO4 solution has a more severe erosion effect than the MgSO4 solution when other conditions remain constant. Finally, X-ray diffraction is conducted to identify the phase of the crystalline material in the specimen. This study will be beneficial in the application of foamed cement paste in regions with salt-rich soils.

Corrosion behaviour of FeCoNiCrAl high-entropy alloy in molten NaCl–KCl–MgCl2 chloride salt

Molten NaCl–KCl–MgCl2 is becoming a potential heat transfer fluid (HTF) and thermal energy storage (TES) material in the third generation of concentrated solar energy power (CSP) stations due to its excellent heat storage-capacity and thermal stability. However, the strong corrosion of the molten chloride salt at high temperature limits its industrial application. In this study, the corrosion behaviour of FeCoNiCrAl HEA with BCC + FCC phase structure in molten NaCl–KCl–MgCl2 (24.5–20.55–54.95 wt-%) at 650 °C under argon was investigated by a combination of weight loss and electrochemical methods. The results show that, the corrosion of FeCoNiCrAl HEA in molten chloride salt mainly manifests as the selective dissolution of Fe and Cr. With the further increase of immersion time, oxides gradually crack and slightly flake, resulting in large weight loss of FeCoNiCrAl HEA.

Use of a natural rock material as a precursor to inhibit corrosion of Ti alloy in an aggressive phosphoric acid medium

The mechanism of interaction between magnesite mineral and phosphoric acid (0.001–0.5 M) in addition to the determination of the protective properties for Ti alloy (working electrode) in phosphoric acid both with and without an inhibitor have been investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. Results of electrochemical tests show that the corrosion resistance of titanium alloy in phosphoric acid solution only increased and hydrogen production decreased by either decreasing acid concentration or increasing immersion time associated with the thickening of the oxide film formed on the alloy surface. On adding magnesite, the corrosion resistance of Ti alloy is enhanced by increasing the phosphoric acid concentration (0.001–0.5 M) due to the formation of sparingly soluble magnesium phosphate film on the alloy surface that inhibits the effect of increasing hydrogen evolution reaction due to the pH value decreases. The increasing adsorption behavior of the magnesite inhibitor and decreasing its diffusion were deduced from EIS measurements. Thus, the addition of 3% magnesite minimizes the corrosion by forming a new protective film (Mg3(PO4)2), which differs from the traditional passive film and prevents the effect of the increase of hydrogen evolution. The surface morphology and chemical composition of the tested alloy were determined using scanning electron microscopy (SEM), Fourier transform Infra-Red spectroscopy (FTIR), X-ray diffraction (XRD), X-ray Fluorescence (XRF) and In situ Raman spectroscopy.

Preparation and Corrosion Resistance of OMMT/EP Composite Coatings in Sulfur-Containing Sodium Aluminate Solution

Organic montmorillonite (OMMT) was prepared from Na-montmorillonite (MMT) by Hexadecylamine (HDA) modification. The composite material has good smoothness, acidity, and salt resistance. OMMT was characterized using small-angle X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and a video optical contact angle measuring instrument. The results showed that the layer spacing was enlarged from 1.44 nm to 2.87 nm after the modification, and the hydrophobicity performance was greatly improved. The organic modification of MMT was successful. The surface morphology, roughness, and anticorrosion properties of the organic montmorillonite/epoxy (OMMT/EP) composite coating were investigated and compared with those of the epoxy (EP) coating. The OMMT/EP composite coating had a flatter surface than the EP coating. The roughness was reduced from 65.5 nm to 10.3 nm. The electrochemical impedance spectroscopy showed that the composite coating’s thickness positively affected its anticorrosion performance, the corrosion current density (Icorr) decreased with the increase in thickness, and its maximum impedance was much larger than that of EP coating. The protection efficiency of the OMMT/EP composite coating was 77.90%, which is a significant improvement over the EP’s 31.27%. In addition, the corrosion resistance of the composite coating gradually decreased with increasing immersion time, but the change was insignificant.

Efficacy of Ga3+ ions on structural, biological and antimicrobial activity of mesoporous lithium silicate bioactive glasses for tissue engineering

Mesoporous bioactive glass nanoparticles (MBGNPs) containing therapeutic ions have shown significant promise in the realm of hard and soft tissue repair and regeneration, owing to their multifunctional biological properties. In this study, gallium-incorporated silica-based gallium incorporated MBGNPs (Ga-MBGNPs) with fixed amount of Li2O (8 mol %) were synthesized using an emulsion-assisted sol-gel method. The impact of Ga2O3 integration into the silicate glass network was evaluated by investigating the microtextural properties. The results confirmed the production of spherical-shaped, nano-sized, amorphous particles with an enhanced specific surface area and ordered hexagonal meso-porosity (10–20 nm) in the developed Ga-MBGNPs. The in vitro bioactivity, assessed through hydroxyapatite (HAp) layer formation in simulated body fluid (SBF), over varying time intervals (0, 1, 3, 7, 14 & 21 days), revealed pronounced formation of short rod-like carbonated HAp with increasing immersion time and Ga3+ content in all glasses. However, a delayed apatite formation was observed for composition-dependent Ga-4 and Ga-5 MBGs during the initial incubation periods (1, 3, and 7 days). Further, the presence of Li + ions along with Ga3+ enhanced the apatite deposition when compared with the only Ga3+ inclusion. Evaluation of degradation rate and pH values indicated enhanced apatite formation with lower Ga ion content, while a slight reduction was noted with higher Ga ion content, attributable to the presence of reactive Si–O–Si bonds. Furthermore, analysis using a Zeta potential analyzer confirmed the dispersibility and bioreactivity of all glass powders owing to their higher negative surface charge. Moreover, Ga-MBGNPs exhibited notable antimicrobial effects against both E. coli and S. aureus bacteria due to the release of Ga3+ ions. Overall, the findings suggest that the incorporation of Ga in MBGNPs renders them potential multifunctional candidates for expediting the healing of bone tissue injuries in biomedical applications.

Arachis hypogaea’s concentration effect on AISI 1020 carbon steel for corrosion protection

The effects of inhibitor concentration on the corrosion rate and inhibition efficiency of AISI 1020 steel in an acidic and alkaline environment were investigated by means of weight loss measurement at an interval of 7 days and 14 days. To carry out this investigation, the Arachis hypogaea hull was extracted and concentrated in various weight percentages. The inhibition efficiency increased with the increased concentrations of AISI 1020 steel that were immersed in acidic and alkaline solution in the absence and presence of varying inhibitor concentrations of Arachis hypogaea hull extracts. The corrosion behavior, including the corrosion rate, is meticulously characterized through the corrosion rate analysis. The results showed that there is an increase in inhibition efficiency with an increase in inhibitor concentration and that there is a decrease in inhibition efficiency with an increase in immersion time. The organic inhibitor (Arachis hypogaea hull) produced the best inhibition efficiency of 96.4% at a 30% concentration. From the result obtained, Arachis hypogaea hull extracts revealed that it is best suited for inhibition of corrosion of mild steel in both acidic and alkaline environments. The goal of this research paper is to develop a comprehensive understanding of the corrosion inhibition and adsorption mechanisms associated with the implementation of the Arachis hypogaea hull as a natural corrosion inhibitor.