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Lawsonia inermis Linn Leaf extract has been evaluated in alkaline solutions for its influence on electroless Ni–P alloy deposition on mild steel. During electroless plating, the effect of experimental processing conditions on deposition rate is investigated. Bath compositions and operational parameters have been optimized. The findings indicate that increasing the volume of additives from 0.5mL to 5mL improves the inclusion rate of electroless Ni–P alloy coating. In the absence of a complexing agent, additive Lawsone exhibits additional structural features and phases. The deposition rate and the corrosion rate of the Ni–P deposits were estimated, respectively, from the weight loss after a period of time. It is recommended to replace sodium citrate with Lawsone.Lawsone’s effect acting as a complexing agent on Ni–P electroless coating was explored utilizing SEM, EDAX, AFM, FTIR, and XRD, as well as corrosion investigations. Polarization and electrochemical impedance spectroscopy are used to assess the corrosion efficiency.

In this work, the influence of laser pulse trains on thin mild steel sheet blades is investigated. The method is based on varying the duty cycle (DC) of a pulsed RF slab CO₂ laser during the process of laser percussion drilling. Here, an experimental methodology to correlate laser parameters and their effects on the characteristics of the melting material ejected was carried out. In the experiments, the interaction time such that of 5%, 10%, and 15% DC were considered for the pulse trains. Results showed a significant effect on the characteristics of melt material ejection during laser percussion. We demonstrate that it was not evident the influence and molten material for pulse width of less than 500 μs and larger than 4500 μs, respectively, when having 5% DC; spatter formation (droplets) for 10% and 15% DC with pulse periods > 2000 μs; debris formation (re-solidified material) at pulse periods from 200 to 1250 μs at 15% DC.

The corrosion inhibition of mild steel in 1 M H₂SO₄ in the presence of polyvinylpyrollidone (PVP) and polyacrylamide (PA) as inhibitors at 30–60°C was studied using gravimetric and gasometric techniques. The inhibition efficiency (1%) increased with increase in concentration of the inhibitors. Increase in temperature increased the corrosion rate in the absence and presence of inhibitors but decreased the inhibition efficiency. Both PVP and PA were found to obey Temkin adsorption isotherm and Kinetic-Thermodynamic Model of El-Awady at all the concentrations and temperatures studied. Phenomenon of physical adsorption is proposed from the activation parameters obtained. Thermodynamic parameters reveal that the adsorption process is spontaneous. PVP was found to be a better inhibitor than PA.

The effect of two pyridin-pyrazol derivatives, N-[(3,5-dimethyl-1H-pyrazol)methyl]pyridine-2-amine (TB5) and 5-bromo-N-[(3,5-dimethyl-1H-pyrazol)methyl]pyridine-2-amine (TB6), newly synthesized, on the corrosion of mild steel in 1.0 M HCl was investigated by weight-loss and various electrochemical techniques. Results obtained reveal that these pyridin-pyrazol derivatives perform excellently as corrosion inhibitors for mild steel in hydrochloric solution. Polarization curves showed that both TB5 and TB6 are mixed-type inhibitors in acidic medium. A kinetic study of steel in uninhibited and inhibited acid for TB6 was also achieved to provide suitable investigations on corrosion inhibition mechanism in 1.0 M HCl solution. The effect of concentration and temperature on the inhibiting efficiency has been examined. The thermodynamic parameters for both dissolution and adsorption processes were calculated and discussed for TB6. The adsorption of inhibitor TB6 on the mild steel surface obeys the Langmuir adsorption isotherm equation.

The inhibitive characteristics of aqueous extracts from mangrove (Rhizophora apiculata) bark and leaf on the corrosion of mild steel (MS) coupon in 1 M HCl were examined by means of the gravimetric measurement (weight loss), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The MS surface morphologie were investigated using field emission scanning electron microscopy (FESEM) with Energy Dispersive X-Ray Analysis (EDX) at 120h in the presence and absence of green inhibitors in corrosive medium. Respective inhibition efficiencies of 68.1% and 59.0% were obtained when exposed to 10% v/v Rhizophora apiculata solution for 72h. Examination of the adsorption behavior of the solutions indicated the Langmuir isotherm model as being the most likely relevant adsorption mechanism. In addition, polarization measurements showed that both bark and leaves extract inhibitors act via mixed type inhibition.

The synergistic effect of halide ions such as KCl, KBr and KI on the corrosion inhibition of mild steel in 1 N sulphuric acid by $\gamma$-2,c-6-diphenyl-t-3-methyl piperdin-4-ones with semicarbazone (01SC), $\gamma$-2,c-6-diphenyl-N-methyl-t-3-ethyl piperdin-4-ones with semicarbazone (02SC) and 2,6-diphenyl-t-3-ethyl piperdin-4-one with semicarbazone (03SC) has been examined by weight loss method, potentiodynamic polarization measurements and electrochemical AC impedance spectroscopy. Results show that substituted $\gamma$-2,c-6-diphenyl piperidin-4-ones with semicarbazone act as the perfect corrosion inhibitors and their inhibition efficiency increases with the addition of halide ions. The inhibitor (01SC) shows the inhibition efficiency of 78.28% (0.2mM) by using a weight loss method. The influence of I${}^{-}$, Br${}^{-}$ and Cl${}^{-}$ anions raises the inhibition efficiency of the substituted 2,6-diphenyl piperidin-4-ones with semicarbazone due to the synergistic effect. The synergistic effect of halide ions was formed in the following order: KI $>$ KBr $>$ KCl.

Due to the study of marine corrosion of mild steel, in order to simulate the corrosion conditions of enamel coatings in seawater, enamel coatings applied on mild steel were immersed in 3.5wt.% NaCl liquor and the related corrosion features and behavior of enamel were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and evaluated by electro-chemical method such as potentiodynamic polarization testing. Under the appropriate heat treatment system, the enamel coatings sintered on the same kind of mild steel at different temperatures were studied: all enamel samples were within the temperature range from 710${}^{\circ }$C to 830${}^{\circ }$C, the heat treating process at the microstructural level was evaluated and correlated with corrosion resistance properties. All the enamel coatings were characterized and it was observed that the enamel coatings that showed excellent corrosion resistance when sintered at a temperature of 810${}^{\circ }$C can offer a better physical barrier than other temperatures because of their better bonding force and dense microstructure with less pores.

The corrosion hindrance impact of Syzygium aromaticum fruit extract has been analyzed on mild steel (MS) corrosion in 0.5M H₂SO₄ by utilizing weight reduction estimations, potentiodynamic polarization estimations and electrochemical impedance spectroscopy (EIS) procedures. This Eugenol- and Eugenol-acetate-containing extract diminishes the corrosion rate of MS in acidic medium. The greatest corrosion restraint effectiveness was observed at 500mg/L inhibitor concentration in 0.5M H₂SO₄. The adsorption of Syzygium aromaticum extract on the surface of MS has been analyzed by utilizing atomic force microscopy (AFM), scanning electron microscopy (SEM) study and spectroscopic strategies.

This work aims at synthesis and characterization of 2,2${}^{\prime }$-dibenzimidazolyl butane as an effective corrosion inhibitor of mild steel in sulfuric acid solution. A simple and efficient method for its synthesis in described. The chemical structure and surface morphology of 2,2${}^{\prime }$-dibenzimidazolyl butane were characterized by mass spectrometry (MS), Fourier transform infrared (FTIR), Raman, ¹H, ${}^{13}$C NMR spectroscopy and transmission electron microscopy (TEM). Its thermal decomposition and its variation in mass was studied by thermogravimetric analysis (TGA) coupled with differential thermal analysis (DTA). The molecular mass of 2,2${}^{\prime }$-dibenzimidazolyl butane was determined to be at 290g/mol and its degradation was achieved at 455^∘C. Then, the corrosion inhibition efficiency of 2,2${}^{\prime }$-dibenzimidazolyl butane was studied with various concentrations in 0.5 M H₂SO₄ solution for mild steel by the potentiodynamic polarization and the electrochemical measurements. According to the results of electrochemical impedance spectroscopy, the inhibition efficiency decreased with concentration and reached its maximum (95.5%) at 100ppm. The polarization measurements showed that the prepared inhibitor acts as a cathodic type inhibitor. The mass loss tests are in accordance with the results of electrochemical measurements.

The study of the corrosion inhibition of mild steel in acid medium 1 M HCl by the Schiff base compounds named {4,4′-Bis(pyrrole-2-carboxaldehyde) diphenyl diimino sulfide (L1) and 4,4′-Bis(thiophene-2-carboxaldehyde) diphenyl diimino sulfide (L2)} was carried out using various techniques: weight loss measurements, polarization curves, electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The influence of the concentration, immersion time and temperature was examined and the mode of adsorption of these inhibitors on the surface of the metal was highlighted by assigning the appropriate isotherm. The experimental results indicate that these compounds are effective corrosion inhibitors and the inhibitory competence rises with increasing inhibitor concentration. The adsorption of these compounds on the mild steel surface obeys the isotherm of Langmuir. The correlation between the molecular structures and the inhibitory properties of the compounds studied was performed using the Density Functional Theory (DFT) method. Furthermore, molecular dynamics (MD) simulation has been taken into account. The results indicate that the adsorption energy of L1 was less than L2, which is in accordance with the experimentally determined inhibition effect.

Canthium parviflorum leaf extract (CPLE) was utilized for corrosion prevention against mild steel (MS) in 0.5molL${}^{-1}$ H₂SO₄ test medium. Standard corrosion measurement techniques (gravimetric and electrochemical) were employed for this purpose. Gravimetric tests clearly confirmed that the prepared CPLE efficiently performs as corrosion inhibitor. Potentiodynamic polarization measurements (PPM) and electrochemical impedance spectroscopy (EIS) measurements were performed in order to analyze the charge transfer process of CPLE. Polarization curves indicate that CPLE acts through mixed mode inhibition. Impedance study reveals that the CPLE additives enhances the charge transfer resistance values and conversely decreases values of double layer capacitance. Scanning electron microscopy (SEM), Ultraviolet-Visible (UV-Vis) spectroscopy analysis and Fourier-Transform Infrared spectroscopy (FTIR) were done to confirm the Fe-CPLE complex formation on MS. The effect of temperature reveals that the inhibition efficiency increases with decrease in temperature and increase in concentration of CPLE (maximum of 4mgL${}^{-1}$). The adsorption of CPLE shows that it obeys Langmuir’s isotherm model with free energy of adsorption, $\mathrm{\Delta }{G}_{\mathrm{\text{ads}}}=-1.76$kJ mol${}^{-1}$. A suitable adsorption model is also proposed.

Continuing to study the inhibition of corrosion, 5,5-diphenyl-2-thioxoimidazolidin-4-one (PTI) has been tested as a corrosion inhibitor for mild steel (MS) in an aggressive 1 M HCl solution by chemical and electrochemical techniques: weight loss, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis, UV-Visible. Inhibitory efficacy increases with increasing inhibitor concentration and decreases with increasing temperature. The studied inhibitor is more efficient (99.2%) at 298 K at an optimal concentration of 1mM. The PDP study revealed that PTI behaved as mixed type of inhibitor. In addition, the PTI inhibitor obeys the single layer adsorption isotherm of Langmuir. The quantum chemical calculations, molecular dynamic (MD) simulation studies fairly well agreed with the experimental measurements.

The inhibition effect of synthesized corrosion inhibitor namely 5,5^′-(1,4-phenylene)bis($N$-phenyl-1,3,4-thiadiazol-2-amine) (PBPA) on the corrosion of mild steel in 1-M hydrochloric acid environment are examined by gravimetric techniques at various temperature (303–343 K). The synthesized inhibitor concentrations are 0.1–0.5mM. The inhibition efficiency increased with the increase of the inhibitor concentration. The inhibition efficiency reached 94% at the highest studied concentration of 0.5mM for 5h of immersion time and 303K. Moreover, the inhibition efficiency decreased with the temperature increase. The adsorption of tested inhibitor molecules on the surface of mild steel follows the Langmuir adsorption isotherm. The studied inhibitor molecules showed excellent inhibition since PBPA molecules have nitrogen and sulfur atoms in addition to phenyl and thiadiazol rings which were linked together in conjugation system.

The corrosion inhibition performance of novel synthesized thiosemicarbazide derivative namely, 2-isonicotinoyl-N-phenylhydrazinecarbothioamide (IPC) on the mild steel coupon surface in 1M hydrochloric acid solution is investigated by weight loss measurements. The adsorption parameters of the IPC on the mild steel coupon surface have been evaluated and the surface morphology of the tested mild steel is studied by scanning electron microscope (SEM) technique. The results of this study demonstrate a significant inhibitor (IPC) for mild steel and showed the highest inhibitive efficiency of 96.3% at 5mM as optimum studied inhibitor concentration. The adsorption of IPC molecules on a mild steel coupon surface is obeyed completely by the model of Langmuir adsorption isotherms. SEM has been applied to analyse the layer of IPC molecules which formed on a mild steel coupon surface as a protective layer. The inhibition efficiency (IE) of IPC from weight loss techniques and SEM analysis was harmonic with each other. The Density Functional Theory (DFT) computations have been applied to evaluate the adsorption sites of the IPC molecules and the quantum chemical calculations correlation of IPC molecules with methodological results are discussed. The energy of the highest occupied molecular orbital (EHOMO) shows a significant tendency of the IPC molecules to donate pairs of electrons to the iron atoms on the surface of mild steel. The energy of the lowest unoccupied molecular orbital (ELUMO) for IPS molecules reveals a high tendency to accept electrons from iron atoms on the surface of mild steel.

In this work, we have tested a new inhibitor formulation that is effective, economically efficient and in accordance with environmental legislation. The inhibitor tested is the crude extract of the oat plant (denoted as OE) obtained by the reflux method in the water. This extract is then used as a corrosion inhibitor of mild steel in 3% NaCl. This study was carried out by using electrochemical polarizations, Electrochemical Impedance Spectroscopy and gravimetric techniques. The results obtained showed that this extract satisfactorily inhibits the dissolution rate of mild steel. The inhibition efficiency increases with inhibitor concentration and reaches 72% at 5g$\cdot$L${}^{-1}$ of oat extract. Polarization data indicate that the extract acted as mixed type. The adsorption of the inhibitor on the mild steel surface in 3% NaCl follows the Langmuir adsorption isotherm. SEM analysis of the electrode surface condition confirms the results obtained.

Friction stud welding process is a suitable candidate in joining stud fasteners for steel structure buildings, military vehicles, automobiles, aircraft, ocean liners, bridges, ship buildings, etc., The peak temperature for welding is achieved by converting mechanical energy to thermal energy at the sample interface without the use of electric energy from other sources because it is a solid-state process. The study of the thermal behavior of different metals during friction stud welding is very important since it is a thermal energy process. However, there is no good thermal model for the friction stud welding process. In this work, the generation of heat flux at the interfacial area of two distinct metals, namely aluminum and mild steel, is calculated using a mathematical model. The temperature at the interfacial region, which plays a significant role in the quality and strength of the weld component, is particularly focused on experimentation and analytical modeling. In the experimentation, a noncontact type infrared thermometer is used to measure temperature directly. The temperature profile was determined by the finite difference method based on thermal resistance and capacitance formulation at transient conditions. The obtained mathematical results are compared with the experimental results at the distance of 5 and 10mm from the welded interface. The computed temperature profile is in good agreement with the experimental data on the heating side and with a minimum degree of deviation in the cooling part. The maximum percentage of error for the 5mm interface is 3.349 and for the 10mm interface is 2.857. This deviation is due to the zero-axial shortening assumption in the analytical model. Besides, the temperature characteristics of the welded are analyzed at various time increments by numerical simulation. As a result, the predicted temperature is more on the aluminum side compared to the mild steel due to a change in thermal properties. This proposed thermal model would be helpful to improve the design and manufacture of welding machines.

Numerical simulations were conducted to validate computational and constitutive models for steel materials through dynamic material tests involving both tension and compression. These simulations involved the numerical modeling of the split Hopkinson pressure bar (SHPB) apparatus, with the appropriate loading applied directly in compression and indirectly in tension. To induce a tensile wave within the specimen, a shoulder, such as a coupler or collar, was interposed between the bars. The simulations were carried out using the LS-DYNA finite element code. In these numerical simulations of the SHPB tests, the MAT-15 Johnson–Cook material model was applied to represent mild steel. The resulting stress–strain relationships obtained under both compression and tension conditions were subsequently compared to corresponding experimental data. The primary objectives of these simulations were to determine the optimal placement of strain gauges on both the input and output bars of the tensile SHPB setup. Additionally, the simulations aimed to assess the influence of the gauge length-to-diameter ratio on the behavior of the mild steel specimen subjected to dynamic tension and compression. The results showed that the pulse produced due to the mechanical mismatch of the element at boundaries can be avoided using the length of the input bar smaller than the output bar. Further, the location of the strain gauge in the case of the output bar should be toward the output bar-shoulder interface, while in the case of the input bar, it should be considered at the center of the span of the bar.

Joining of metal with ceramics has become significant in many applications, because they combine properties like ductility with high hardness and wear resistance. By friction welding technique, alumina can be joined to mild steel with AA1100 sheet of 1mm thickness as interlayer. In the present work, investigation of the effect of friction time on interlayer thickness reduction and bending strength is carried out by factorial design. By using ANOVA, a statistical tool, regression modeling is done. The regression model predicts the bending strength of welded ceramic/metal joints accurately with ± 2% deviation from the experimental values.