HCl Environment Research Articles

Corrosion Inhibition of Cold-rolled Low Carbon Steel with Pulse Fiber Laser Ablation in Water

This study aims at the use of a fiber laser for modifying the surface properties of cold-rolled low carbon steel via a pulse laser ablation technique in water. The effect on the corrosion behavior of the fiber laser-treated metal surface was investigated in NaCl and HCl environments. Electrochemical tests showed significant improvement in the corrosion resistance of the laser-treated sample in NaCl, with an increase in open-circuit potential (OCP) from − 0.65 to − 0.60 V and an inhibition efficiency of 89.22% as obtained from the impedance study. Such improvement was less significant in an acidic environment. Lower corrosion rates of 20.9 mpy and 5.819 × 103 mpy were obtained for the laser-treated samples in neutral and acidic electrolytes, respectively, than the corrosion rates obtained for the as-received samples (33.2 mpy and 11.98 × 103 mpy). Morphological analysis indicated a passive film built by spherical grains of regular size on the metal surface after laser treatment. The corrosion inhibition effects in NaCl were evident by the nonexistence of the common corrosion products of lepidocrocite and crystalline structures that were seen on as-received samples; only polyhedral crystals with micrograins grown on them were seen covering the laser-treated surface. Therefore, the laser treatment using a fiber laser source improved the corrosion resistance of cold-rolled low carbon steel.

Optimization of an efficient, economic and eco-friendly inhibitor based on Sesbania grandiflora leaf extract for the mild steel corrosion in aggressive HCl environment

PurposeThis paper aims to evaluate the inhibitive action of different concentrations of Sesbania grandiflora leaf extract on the mild steel corrosion in an aggressive HCl medium under different experimental conditions.Design/methodology/approachWeight loss investigation, open-circuit voltage analysis, Tafel polarisation, AC impedance analysis, etc. were used for the evaluation of inhibition efficiency. The influence of immersion period on inhibition efficiency was evaluated. The mechanism of action of the inhibitor is also discussed. Infrared (IR) spectroscopy and energy-dispersive X-ray spectroscopy analysis were used to characterise the passive film.FindingsThe results suggested that 10,000 ppm solution has maximum inhibition efficiency of 98.01 per cent at room temperature, while 1,000 ppm solution also exhibited a better efficiency of about 96.16 per cent. Efficiency of inhibitor solution was found to increase with an increase in its concentration. Polarisation study proposed the solution as an anodic inhibitor. Impedance study confirmed the formation of a protective layer over the surface of the specimen, and the constituents of the film were identified using IR spectroscopy. Stability of the film adsorbed on the steel was cleared from the steady open-circuit potential value. Study on action of the inhibitor under accelerated conditions revealed the fact that the efficiency of extract in preventing corrosion is good under stimulated conditions also.Practical implicationsThe action of inhibitor sustains for a sufficient time period and could sustain under stimulated conditions. Hence, its application is practically possible in industries. The proposed inhibitor is widely available and is environmentally safe.Originality/valueHCl is an industrially important chemical used for acid cleaning, acid pickling, etc. HCl was used as an aggressive corrosion environment. As the chances for mild steel to be in contact with HCl were very high, it was important to develop an efficient, economical and eco-friendly inhibitor for corrosion.

Influence of 1-butyl-1-methylpiperidinium tetrafluoroborate on St37 steel dissolution behavior in HCl environment

ABSTRACTThe efficacy of 1-butyl-1-methylpiperidinium tetrafluoroborate (BMPTFB) in retarding St37 steel corrosion in HCl environment has been examined using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), dynamic-EIS (DEIS), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) techniques. Results from all applied methods reveal that BMPTFB is effective in suppressing St37 dissolution in the studied corrosive medium. Inhibition efficiency of 88% has been achieved by 4 mM BMPTFB. From DEIS results, BMPTFB is found to perform better as corrosion inhibitor at longer immersion time. The charge transfer resistance of the metal is raised in the presence of 4 mM BMPTFB from 378 to 744 Ω cm2 at 1 h and further increased to 867 Ω cm2 at 4 h. BMPTFB, according to PDP result behaves as mixed-type corrosion inhibitor. Corrosion inhibition by BMPTFB is via adsorption which can best be explained using El-Awady kinetic/thermodynamic adsorption isotherm. Kads and values indicate that physisorption is the mechanism of adsorption of BMPTFB molecules onto St37 surface. The presence of BMPTFB molecules on St37 surface has been verified by SEM and FTIR.

Anti-corrosion Properties of Areca Palm Leaf Extract on Aluminium in 0.5 M HCl Environment

The aluminium corrosion inhibition behaviour in the presence of Areca palm leaves (AL) extract in hydrochloric acid (0.5 M) medium was examined by chemical (mass loss), AC impedance spectroscopy, potentiodynamic polarization and surface (scanning electron microscopy) methods. Aluminium protection rates increased with an increase in the amount of AL extract to the 0.5M HCl system and decreased with increasing in the contact time of aluminium metal and temperature of 0.5M HCl solution. Arrhenius equation was applied in the determination of activation energy values. The other activation parameters such as activation entropy and enthalpy values were obtained from the transition state plot. The adsorption of AL extract species on the Al surface in 0.5M HCl solution follows the Langmuir adsorption mechanism. Tafel curves reflect the mixed (both anodic and cathodic) inhibition behaviour of green inhibitor (AL extract species) on electrode surface (Al) in 0.5M system. Impedance method indicates that the Al dissolution in hydrochloric acid environment was fully hindered by charge transfer process. The Al surface morphology was examined by applying scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Keywords: Aluminium, Areca palm leaves, weight loss, Arrhenius equation, Langmuir adsorption

Anti-corrosion performance of the synergistic properties of benzenecarbonitrile and 5-bromovanillin on 1018 carbon steel in HCl environment

The synergistic properties of the combined admixture of benzenecarbonitrile and 5-bromovanillin (BNV) on the corrosion resistance of 1018 carbon steel in 1 M HCl was analysed with potentiodynamic polarization technique, weight loss method, micro-analytical studies and ATF-FTIR spectroscopy. Results obtained show the admixed organic compound was effective with optimal corrosion inhibition values of 99.33% and 90.34% at 1.25% BNV concentration from both electrochemical methods due to the effective inhibition action and passivation characteristics of the protonated inhibitor molecules in the acid solution. Primary amines, stretch alkyl halides and C-H triple bond functional groups of the molecules were observed to actively adsorb during the corrosion inhibition reaction from ATF-FTIR spectroscopic analysis. Calculations from thermodynamic evaluation confirmed cationic adsorption mechanism to be chemisorption obeying the Langmuir and Frumkin adsorption isotherm. Micro-analytical observations of the inhibited carbon steel morphology significantly contrast the unprotected steel due to visible surface deterioration and presence of micro/macro-pits. The organic derivatives showed mixed type inhibition reactions.

Investigation of Chloride Poisoning Resistance for Nitrogen-Doped Carbon Nanostructures as Oxygen Depolarized Cathode Catalysts in Acidic Media

HCl electrolysis used to manufacture Cl2, a compound of high industrial value, suffers from its high energy requirements. Significant energy savings can be attained by an alternative oxygen depolarized cathode (ODC)-based process where oxygen is reduced at the cathode instead of protons. Though the ODC process is extremely attractive, the state of the art catalysts for oxygen reduction reaction (ORR) suffer from chloride ion poisoning and/or involve toxic chemicals such as hydrogen sulfide (H2S). In the present work, we demonstrate that non-metal containing CNx catalysts do not get deactivated upon exposure to chloride ion environment unlike Pt/C or RhxSy/C where significant chloride ion poisoning was observed. The synthesis of these CNx materials is also extremely facile and scalable. In addition, the performance of the synthesized CNx catalysts was found to be very stable in HCl environment. Thus, the results presented here demonstrate the promise of CNx materials as alternative catalysts for ODC-based HCl electrolysis process to manufacture Cl2 in a sustainable and safer way.

Studies on the Inhibitive Properties of Boscia senegalensis in Aluminium-HCl environment

The extracts of Boscia senegalensis was study as corrosion inhibitors for Aluminium in 1M HCl environment using gravimetric and linear polarization methods. The result shows that the extract inhibits the corrosion of aluminium by elongating the latency periods of the metal beyond in the absence of the inhibitor. The results from gravimetric measurements illustrate increase in inhibition efficiency with increment in extract concentration. Linear polarization plots show that the mode of inhibition was mixed type. The observed decrease in corrosion rate was due to adsorption of the extracts on the surface of the metal which obey the Langmuir adsorption isotherm. Adsorption of the extract depends on its chemical composition which showed the presence of various phytochemicals like flavonoids, steroids, tannins and phenolic compounds etc. which has oxygen atoms with lone pair electrons for co-ordinate bonding with metal.

Synthesis and characterization of some nonionic surfactants as corrosion inhibitors for steel in 1.0 M HCl (Experimental and computational study)

Synthesis, adsorption and corrosion inhibiting effect of three surfactants consist of Schiff bases as hydrophobic part and poly ethylene glylcol (poly ethylene oxide) as hydrophilic part on steel in 1.0M HCl was investigated using weight loss, Electrochemical Impedance, potentiodynamic polarization techniques and computational methods. The experimental findings revealed that these compounds inhibited the corrosion reaction in 1.0M HCl environment. Polarization curves revealed that the used inhibitors represent mixed-type inhibitors. There was a good correlation between the experimental results and quantum chemical parameters of the surfactants. Molecular dynamic simulation indicated that these surfactants were adsorbed on the metal surface.

Corrosion inhibitory properties of elephant grass (Pennisetum purpureum) extract: Effect on mild steel corrosion in 1 M HCl solution

Corrosion inhibition and adsorption characteristics of elephant grass extracts on mild steel in 1M HCl solution were investigated. Mass loss, corrosion rate measurements, inhibition efficiency, atomic adsorption spectroscopy (AAS), FT-IR spectroscopy and scanning electron spectroscopic analysis were used to assess the inhibitory properties of the extract in the acid solution. The results show that the steel dissolution rate in the acidic solution was sensitive to the extract concentration as mass loss and corrosion rates were observed to decrease with increase in the extract concentration. The inhibition efficiencies were averagely above 95% at room temperature increasing with increase in concentration of the extract but decreases with increasing temperature. FTIR results showed that the inhibition was essentially by absorption through the functional groups present in the extract while the activation energies and Langmuir adsorption isotherms confirm the mechanism to be physical adsorption. The SEM images of the corroded substrates confirmed pitting as the primary corrosion mechanism which was substantially mitigated with the use of the extract. Overall, the elephant grass extract was found to be efficient for corrosion inhibition of mild steel in HCl environment.

Biomaterials for corrosion protection: evaluation of mustard seed extract as eco-friendly corrosion inhibitor for X60 steel in acid media

The toxic nature of most organic and inorganic corrosion inhibitors has necessitated the search for corrosion inhibitors with an excellent environmental profile. The present work is focused on the widening utilization of plant extracts for metallic corrosion control and reports on the corrosion inhibition effect of mustard seed extract (MSE) for typical X60 pipeline steel in 2 M HCl and 1 M H2SO4 solutions. Gravimetric and electrochemical (electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization) methods were employed. The effect of immersion time and temperature on the corrosion inhibition effect of the plant extract was also studied. Results obtained show that MSE inhibited the corrosion of steel in both media which was more pronounced in H2SO4 than in HCl environment. Inhibition efficiency increased with increase in the concentration of the extract but decreased with increase in temperature. The potentiodynamic polarization studies revealed that MSE functions as a mixed-type inhibitor. The corrosion inhibition is assumed to occur via adsorption of the components of the extract on the steel surface which was found to obey Langmuir adsorption isotherm model. The morphology of the corroding steel surface in the absence and presence of the MSE was visualized using scanning electron microscopy.

Effect of HCl on the Formation of TiO2 Nanocrystallites

TiO2 nanocrystals are prepared by pyrolysis of titanium tetrachloride (TiCl4) as precursor in HCl aqueous solution at 80°C. The experimental results show that the HCl concentrations in the synthesizing medium and the following aging are the essential factors affecting the phase formation and phase composition of the resulting TiO2 nanocrystals. The TiO2 suspended in the HCl media is predominant anatase in uniform cluster and the TiO2 deposited in the sedimentation is predominant rutile in the rod-like structure. In the anatase phase, TiO2 crystallites have particle structure of 4–11 nm in mean size depending on the HCl concentration and aging time. In the rutile phase, the mean size of rutile TiO2 is 12-13 nm and there is not much change with HCl environment and aging time. The mean size of TiO2 of around 11-12 nm is considered to be the critical point of phase transition from anatase to rutile in HCl media. Consequence, TiO2 nanocrystallites in pure anatase and rutile phase can be extracted and segregated from the colloidal suspension and the deposited parts in the synthesizing media.

Electrochemical and Morphological Study of Steel in 1 M HCl in the Presence of Task Specific Liquid

In the present study, corrosion inhibition influence of novel cationic surfactant (CS) with imidazole structure (1-methyl-3-octadecane imidazolium hydrogen sulfate) on low carbon steel in 1 M HCl was investigated by implementing weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. Increasing the amount of surfactant adequately leads to an increment of the inhibition efficiency of novel CS. According to the obtained results from EIS measurements, inhibition efficiency was about 34% in the presence of 1 ppm surfactant, increasing to about 96.8% at the 25 ppm (near critical micelle concentration) surfactant concentration. Also the effects of temperature and the synergistic effect between surfactant and NaHSO4 salt were studied. The inhibition efficiency increased with the increase of NaHSO4 concentration and reached the maximum value near 0.1 M and experienced a plummet in the temperature range of 30-50 °C. Potentiodynamic polarization measurements revealed that the surfactant acts as mixed-type inhibitors. Results obtained from weight loss, polarization, and impedance measurements are in proper agreement and confirmed the fact that this surfactant is an excellent inhibitor for low carbon steel in 1 M HCl environment. The surface morphology of inhibited and uninhibited metal samples was investigated by atomic force microscope (AFM) and field emission scanning electron microscope (FE-SEM).

Aqueous extract of Argemone mexicana roots for effective protection of mild steel in an HCl environment

The inhibition effect of aqueous Argemone mexicana root extract (AMRE) on mild steel corrosion in 1 M HCl has been studied by weight loss, Tafel polarization curves, electrochemical impedance spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy techniques. Results indicate that inhibition ability of AMRE increases with the increasing amount of the extract. A maximum corrosion inhibition of 94 % is acknowledged at the extract concentration of 400 mg L−1. Polarization curves and impedance spectra reveal that both cathodic and anodic reactions are suppressed due to passive layer formation at the metal–acid interface. It is also confirmed by SEM micrographs and FTIR studies. Furthermore, the effects of acid concentration (1–5 M), immersion time (120 h) and temperature (30–60 °C) on inhibition potential of AMRE have been investigated by the weight loss method and electrochemical techniques. An adsorption mechanism is also proposed on the basis of weight loss results, which shows good agreement with the Langmuir isotherm.

Comparison between oxidation of Fe–Cr–Al sputter coatings in air and air–HCl environments at 550°C

In biomass fired power plants the superheaters and reheaters are known to be particularly susceptible to chloride induced fireside corrosion. One approach to giving them longer lives is to develop new coatings that are resistant to this type of fireside corrosion damage. This paper reports the initial stages of such an approach using the combinatorial model alloy development method. Physical vapour deposition (PVD) using a two-target magnetron sputtering system (99·95 wt-%Cr and Fe–30 wt-%Al) has been used to obtain a range of coating compositions. The coatings were deposited onto an array of sapphire discs (10 mm diameter; 3 mm thick) placed in front of the targets. This resulted in a group of samples with coatings with a range of different Cr to Fe/Al ratios, which have been characterised using scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) and X-ray diffraction (XRD). Two groups of eleven coatings have been exposed at 550°C for up to 150 h in air and air–315 vppm HCl. Weight change data was gathered from these exposures after 50 and 150 h. After each exposure period, the surfaces of the oxidation/corrosion products were characterised using SEM/EDX and XRD. This analytical data has been used to identify the phases formed and the morphology of the scales generated. The best performing coatings from the mass change data were cross-sectioned to characterise the damage.

QUALITY IMPROVEMENT OF SECONDARY SILUMINS BY USING REFINING-MODIFYING, HEAT AND LASER TREATMENTS

Purpose. As a rule secondary silumins are characterized by lower quality than their primary analogues. During manufacture of alloys a large quantity of intermetallides, first of all on the basis of iron, in their structure is ignored. To achieve the optimum level of properties it is necessary to search for ways to adapt refining-modifying, heat and laser treatments to peculiarities of the structure of secondary Al-Si alloys. Methodology. The research was carried out by using standard methods of metallographic analysis, determination of foundry, mechanical and service properties of alloys according to rotatable plans of multifactor experiments. Findings. It was established, that refining-modifying treatment is a required procedure during manufacture of secondary silumins as it permits to effectively influence the iron-containing phases' segregations by changing their morphology, size and distribution and to increase the effectiveness of further treatment in solid state. It was found that standard modes of heat treatment are not optimal for secondary silumins. Laser treatment has shown high effectiveness in increasing of strength, wear resistance, corrosion and cavitation resistance of secondary Al-Si alloys, and the increased iron content contributed to additional solid solution hardening. Originality. It was established, that after refining-modifying treatment the phase Al5SiFe, which crystallizes in the shape of long stretched plates transformed into phase Al15(FeMn)3Si2 in skeletal or polyhedral shape. The relationship between iron content in secondary silumins and holding time during heat treatment that ensures optimum of mechanical properties was obtained. It was proved that the presence of iron-containing intermetallides Al5SiFe results in the decrease of hardened layer's depth during laser treatment. It was established, that with increasing of iron concentration the corrosion rate of secondary silumins in 3 % NaCl + 0.1 % H2O2 and 10 % HCl environments increases. Practical value. The offered technical solutions are instrumental in upgrading second silumins to the level which allows to utilize them as raw material for making of alloys on the basis of aluminium.

Probing propensity of grade 2205 duplex stainless steel towards atmospheric chloride-induced stress corrosion cracking

The propensity of grade 2205 duplex stainless steel towards atmospheric chloride-induced stress corrosion cracking at 50°C has been investigated. Electron backscatter diffraction has been used to characterise as received and 750°C heat-treated microstructures. Screening tests in chloride-containing aqueous environments were employed to investigate the corrosion behaviour of both microstructures. These tests indicated significantly increased corrosion rates when exposed to HCl or FeCl3-containing environments. Stress corrosion cracking tests with atmospheric exposures for up to 12 months showed selective dissolution of the ferrite, accompanied by stress corrosion microcracks in the austenite. This work demonstrates that grade 2205 duplex stainless steel microstructure may be rendered susceptible to stress corrosion cracking under atmospheric exposure conditions at 50°C.

Corrosion inhibition and adsorption behavior of new Schiff base surfactant on steel in acidic environment: Experimental and theoretical studies

Synthesis, adsorption and corrosion inhibiting effect of new Schiff base surfactant named 4-hydroxy-3-(3-phenyl-allylideneamino)-benzene sulphonic acid2-[2-(2-{2-[2-(2-hydroxy-ethoxy)-ethoxy]-ethoxy}-ethoxy)-ethoxy]-ethyl ether (abbreviated as PAAB) on mild steel in 1.0M HCl were investigated using weight loss, and potentiodynamic polarization techniques. The results revealed that this compound inhibited the corrosion reaction in HCl environment. The results indicated that this inhibitor was adsorbed on the metal/solution interface. Theoretical study of the adsorption behavior of this compound was carried out in the framework of the semiempirical (SE) and molecular dynamics (MD).

Corrosion Characteristics of As-Cast Aluminium Bronze Alloy in Selected Aggressive Media

This research work investigated the corrosion characteristics of aluminium bronze alloy in four selected aggressive media which are H2SO4, HCl, NaOH, and NaCl. Aluminium bronze alloy was produced locally via sand casting method. Copper coils and aluminium materials which constitute waste to the environment were used in producing the alloy. Test specimens were produced from the as cast alloy and immersed in H2SO4, HCl, NaOH, and NaCl environment. The concentrations of the environment were varied as 0.1 M, 0.3 M and 0.5 M. The aluminium bronze produced from sand casting has mechanical properties that are closer to the standards proposed by CDA [1]. The corrosion rate was determined by weight loss method at an interval of 3 days. It was observed that the corrosion behaviour exhibited by aluminium bronze in acidic media followed similar trends in 0.1 M, 0.3 M and 0.5 M respectively. However, the corrosion rates increases with increase in the concentration of H2SO4 and NaCl media, but the attack was more aggressive in HCl medium. The aluminium bronze samples in NaOH and H2SO4 media show gradual decolouration from its as-cast yellow golden colour to brown and dark colour respectively. NaCl environment shows high resistance to corrosion and slight decolouration effect even at increased concentration.

SYNTHESIS AND CHARACTERIZATION OF A NONIONIC SURFACTANT AS A CORROSION INHIBITOR FOR STEEL IN 1.0 M HCL.

Synthesis, adsorption and corrosion inhibiting effect of new nonionic surfactant consisting of 3-[(4-Dimethylamino-benzylidene)-amino]-4-hydroxy-benzenesulphonic acid as hydrophobic part and poly ethylene glylcol (poly ethylene oxide) on steel in 1.0 M HCl was investigated using weight loss and potentiodynamic polarization techniques. The experimental findings revealed that this compound inhibited the corrosion reaction in 1.0 M HCl environment. The results indicated that this surfactant was adsorbed on the metal/solution interface. A theoretical study of the adsorption behavior of this compound was carried out in the framework of the semiempirical (SE) and molecular dynamics (MD).

Screening for Bacillus subtilis group isolates that degrade cyanogens at pH 4.5–5.0

Cyanogenic food crops abound in nature with important crops like cassava forming the staple food for over half a billion people. Detoxification by hydrolysis of cassava cyanogenic glycosides often involves acid fermentation, and in some of these processes Bacillus species are encountered. Forty Bacillus spp. (20 Bacillus subtilis, 11 Bacillus licheniformis, 7 Bacillus sonorensis, 2 Bacillus cereus) isolated from acid fermented primary starters to produce Gergoush, a Sudanese fermented snack, were screened for their ability to grow and to hydrolyze linamarin, the major cyanogen found in cassava at pH levels below 5.0; also the cyanogen amygdalin was assessed. The B. subtilis isolates grew in both HCl and lactic acid environments from pH4.5–6.0 while being able to break down the cyanogenic glycosides. The B. licheniformis and B. sonorensis isolates grew and degraded cyanogens at pH5.0 in a HCl environment, while two B. cereus isolates used in the study showed no breakdown reaction under all conditions tested. One B. subtilis isolate was observed to have substrate specificity between the breakdown of linamarin and amygdalin. We conclude that some Bacillus spp. isolates are important in the microbiological breakdown of cyanogens in cassava fermentations even at pH4.5–5.0 though further investigations are required.