Impact of ultrasound frequency on the corrosion resistance of electroless nickel-phosphorus-nanodiamond plating

The nickel-phosphorus (Ni-P) and nickel-phosphorus-nanodiamond (Ni-P-ND) coatings were deposited on mild steel via electroless plating without ultrasound and under ultrasonic agitation with different frequencies of 25, 50, 75, 100, and 150 kHz. The as-prepared coatings were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The corrosion performance of the fabricated layers was evaluated in 3.5 wt% NaCl solution by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. Results of the corrosion tests demonstrated that deposition under ultrasonic power provided coatings with higher stability in the corrosive environment. The corrosion rate decreased with increasing ultrasound frequency from 25 to 75 kHz but increased with further increase in frequency. This introduced 75 kHz as the optimum ultrasound frequency for electroless plating of Ni-P. It was also observed that the corrosion resistance of the proposed coating was improved through the incorporation of 40 ppm nanodiamond into the Ni-P matrix

Ultrasonic-assisted deposition of Ni-P-Al2O3 coating for practical protection of mild steel: Influence of ultrasound frequency on the corrosion behavior of the coating

In this paper, the precipitation of nickel-phosphorous (Ni-P) electroless coatings including Al2O3 nanoparticles (Ni-P-NA) using ultrasound waves on mild steel has been studied. Deposition process occurred in a lactic plating bath by the autocatalytic method using an ultrasound probe. The effect of radiation frequency on the properties of coatings was investigated, and the optimum frequency was determined. The obtained samples were evaluated for their corrosion resistance, surface morphology, and hardness by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and scanning electron microscopy (SEM). The results showed that ultrasound waves caused an improvement in the corrosion resistance and uniformity of the coatings. Furthermore, five different wave frequencies applied during deposition disclosed the remarkable impact of frequency on the smoothness and corrosion resistance of the resultant coatings. On this basis, the Nyquist diagrams showed that the corrosion resistance of the prepared Ni-P-NA coating at an optimum frequency of 75 kHz was 2.59 kΩ·cm2. This value was about 2.5 times higher than the value obtained for the Ni-P-NA coating deposited without ultrasound power

Electrochemical data and analysis of the protection effect of Citrus Sinensis on mild steel in weak acid electrolytes

Data on the protection effect of Citrus Sinensis oil extracts (CS) on mild steel in dilute H2SO4 and HCl solution was studied. The extract sufficiently protected the steel in both acids with respect to its concentration. CS performed more effectively in HCl compared to H2SO4. Inhibition performance of the extract varied significantly with exposure time. The highest inhibition efficiency of 78.47% and 85.61% was attained at the highest extract concentration in both acids. Inhibition efficiency in both acids decreased with respect to exposure time. Standard deviation showed variation of CS inhibition efficiency was significant at low concentration. Data from numerical assessment showed extract concentration is the statistically relevant factor inducing protection of the steel with statistical relevance of 89.9% and 96.39%. Data showed 58% and 86% of inhibition efficiency data in H2SO4 and HCl solution are above 70% inhibition value at margin of error of ±0.097 and ±0.068

Corrosion inhibition effect of non-toxic -amino acid compound on high carbon steel in low molar concentration of hydrochloric acid

Electrochemical studies of the corrosion inhibition effect of biodegradable 2-amino-4- methylpentanoic acid (LCN) on high carbon steel in 1 M HCl acid was evaluated with potentiodynamic polarization technique, weight loss analysis and optical microscopy. Results show the compound to be highly effective with optimal inhibition efficiencies of 87.46% and 85.88% from the electrochemical test with dominant cathodic inhibition behaviour between 0% and 1.88% inhibitor concentration and anodic inhibition behaviour at 2.81% and 5.63% inhibitor concentration due to changes in the effect of lateral repulsion between inhibitor molecules. Thermodynamic calculations showed chemisorption molecular interaction and adsorption onto HCS surface according to Langmuir, Freundlich and Frumkin isotherm models with correlation coefficients of 0.9991, 0.8727 and 0.9782. Statistical analysis showed inhibitor concentration is only relevant variable responsible for inhibition efficiency. Calculated results from predicted corrosion rate values varied at an average value of 53% from experimental results. Optical microscopy images of LCN inhibited and uninhibited HCS samples significantly contrast each

Adsorption and Quantum Chemical Studies on the Inhibition Potentials of Some Thiosemicarbazides for the Corrosion of Mild Steel in Acidic Medium

Three thiosemicarbazides, namely 2-(2-aminophenyl)-N phenylhydrazinecarbothioamide (AP4PT), N,2-diphenylhydrazinecarbothioamide (D4PT) and 2-(2-hydroxyphenyl)-N-phenyl hydrazinecarbothioamide (HP4PT), were investigated as corrosion inhibitors for mild steel in H2SO4 solution using gravimetric and gasometric methods. The results revealed that they all inhibit corrosion and their % inhibition efficiencies (%IE) follow the order: AP4PT > HP4PT > D4PT. The %IE obtained from the gravimetric and gasometric experiments were in good agreement. The thermodynamic parameters obtained support a physical adsorption mechanism and the adsorption followed the Langmuir adsorption isotherm. Some quantum chemical parameters were calculated using different methods and correlated with the experimental %IE. Quantitative structure activity relationship (QSAR) approach was used on a composite index of some quantum chemical parameters to characterize the inhibition performance of the studied molecules. The results showed that the %IE were closely related to some of the quantum chemical parameters, but with varying degrees. The calculated/theoretical %IE of the molecules were found to be close to their experimental %IE. The local reactivity has been studied through the Fukui and condensed softness indices in order to predict both the reactive centers and to know the possible sites of nucleophilic and electrophilic attacks

Corrosion Inhibition on Mild Steel by Phosphonium Salts in 1M HNO3 Aqueous Medium

The corrosion inhibition on mild steel by phosphonium salts in 1 M HNO3 medium has been investigated by weight loss and polarization techniques. The result revealed that these derivatives are excellent inhibitors. Potentiostatic polarization, impedance and electrochemical noise studies showed mixed type inhibitors. Ellipsometer, quantum chemical and FTIR results indicated Phosphonium bromide derivatives exhibit excellent corrosion protective thin layer performance

A critical review of electrochemical noise measurement as a tool for evaluation of organic coatings

The simplicity of measuring equipment and versatility of data analysis makes electrochemical noise measurement an ideal technique for acquiring electrochemical information about the corrosion behavior of a painted metal relatively quickly. Hence the method has great potential for use in the laboratory as well as in field situations. However, special care must be taken in choosing data acquisition parameters, reference electrodes and symmetry of electrodes in order to achieve reproducible measurements. These areas have been discussed in this review along with methods of data analysis, alternative electrode configurations for on-site measurements and novel applications of the technique

Inhibitive action of gramine towards corrosion of mild steel in deaerated 1.0 M hydrochloric acid solutions

The effect of addition of gramine on mild steel dissolution in deaerated 1.0 M hydrochloric acid was studied through potentiodynamic polarisation curves, electrochemical impedance spectroscopy and gravimetric measurements in the temperature range from 25 °C to 55 °C. Gramine was found to shift the corrosion potentials towards less noble values and decrease both dissolution of mild steel and hydrogen evolution reaction. Gramine did not affect the corrosion reaction mechanism (blocking effect). Results obtained from the several measurement techniques were in good agreement and revealed good inhibition efficiencies in the concentration range (0.75 mM ÷ 7.5 mM) particularly at higher concentrations