Corrosion Rate Of Aluminum Research Articles

Understanding How Structure Influences Electrochemical Behavior When ZnO Is Used to Suppress Aluminum Corrosion in Alkaline Electrolytes

The severe corrosion rate of aluminum (Al), coupled with hydrogen evolution (H2 gassing), is the major roadblock preventing the widespread deployment of Al as the anode material in primary and secondary alkaline batteries. One of the most successful approaches to reduce this corrosion has been the addition of ZnO to the alkaline KOH electrolyte, which results in the spontaneous electroless deposition of a protective metallic Zn film on the Al surface. However, the fundamental structural and electrochemical characterization of Zn on Al as well as the influence of ZnO/KOH composition need to be investigated. This study aims to develop a novel fundamental understanding of the protection mechanism against Al corrosion when zincate (from dissolved ZnO) is added to KOH electrolytes. The effects of both ZnO concentration and KOH concentration are probed. Morphological studies of the spontaneous Zn film were realized using SEM, XRD, N2 adsorption and measurements of real time H2 gas evolution. These were coupled with discharge experiments to create a new structure-function understanding for ZnO protection of Al. It should be noted that electrolytes enabling protective Zn films with good adherence and density were found, and capacities near the Al theoretical capacity were achieved.

Evaluation of corrosion behaviour of aluminum in different environment

The corrosion behaviour of aluminum in hydrochloric, nitric, sulfuric and phosphoric acids was investigated using weight loss method. The results shows that the corrosion rate of aluminium in HCl, H 3 PO 4 , H H 3 PO 4 > H HNO 3 Keywords : aluminum, weight loss, corrosion rate, thermodynamic and kinetic parameters

Effect of nonionic surfactant as an electrolyte additive on the performance of aluminum-air battery

In this work, the aluminum-air battery performance is improved by adding nonionic surfactant (nonoxynol-9) to battery electrolyte (4.0 M NaOH). The efficiency of nonoxynol-9 is determined using hydrogen gas evolution and electrochemical measurements. The surface analysis is explored using scan electron microscope and energy dispersive X-ray spectroscopy. Battery performance is investigated at 20 mA cm−2. The results show that the battery performance is significantly improved by adding nonoxynol-9. This is due to the low corrosion rate of aluminum in 4.0 NaOH solution resulted from physical adsorption of nonoxynol-9 on aluminum surface. The surfactant suppresses the hydrogen gas evolution and increases the anode utilization and capacity density. The maximum inhibition efficiencies of nonoxynol-9 from hydrogen gas evolution and electrochemical measurements are 85.6% and 92.8%, respectively at 2.0 mM. Nonoxynol-9 behaves as a cathodic-type inhibitor and its adsorption complies with Freundlich type isotherm. The adsorption of surfactant on the aluminum surface is emphasized by surface analysis.

Highly Sensitive Colorimetric Detection of Early Stage Aluminum Corrosion in Water Using Plasmonic Gold Nanoparticle Films

AbstractCorrosion remains the major reason for the failure of metallic parts. Therefore, spotting and evaluating the severity of corrosion at its early stages is of great importance. Herein, a novel optical corrosion probe based on plasmonic gold nanoparticles immobilized on aluminum surface is demonstrated. The measurements confirm that the corrosion rate and mechanism of bare aluminum is identical to that of the developed probe. During Al corrosion, the gold nanoparticles are located entirely at the interface between the inner dense and outer porous layers of the formed aluminum oxide. The growth of the inner oxide layer during corrosion prompts a change in the reflection spectra and the appearance of strong coloration that is easily observed by the naked eye. Numerical modeling reveals that these optical changes occur mainly due to light interference within the inner oxide layer, which is located between the plasmonic gold nanoparticles and the underlying reflective aluminum. The ability of the plasmonic probe is further demonstrated to monitor the aqueous corrosion of thin films, bulk and alloyed Al, as well as Al protected by a self‐assembled monolayer of hydrophobic surfactant, and, hence, the wide applicability of the method.

Benevolent Behavior of Arecanut Husk Extracts as Potential Corrosion Inhibitor for Aluminum in both 0.5 M HCl and 0.1 M NaOH Environments

The purpose of present study is to incite the effectiveness of green color arecanut husk extract as an inhibiting agent for aluminum metal in both 0.5 M HCl and 0.1 M NaOH systems. The protection efficiency of green inhibitor was assessed through gravimetric, and Tafel plot (potentiodynamic polarization) techniques. The weight loss experiment was performed in unstirred and stirred test solutions in order to study the stability of the inhibitory protective film on the surface of the aluminum. The influence of temperature and time on adsorption of arecanut husk extracts constituents on the surface of aluminum has been studied. Both Tafel and Nyquist curves measurement after the stabilization period of the aluminum metal in 0.5 M HCl/0.1 M NaOH solution confirmed that the introduction of arecanut husk extract appreciably decreased the rate of aluminum corrosion. The powder X-ray diffraction tool was used to study the nature of green inhibitor and its protective film created on aluminum metal in 0.5 M HCl and 0.1 M NaOH medium. The scanning electron microscopy and atomic force microscopy images confirm that the inhibited aluminum surface is superior compared to uninhibited aluminum surface.

DETERMINATION OF ATMOSPHERIC CORROSION RATE OF METALS IN 12 VIETNAMESE AREAS

The corrosion of materials is a result of complex impact from many climatic factors such as temperature, humidity, air pollutant content in the air, rainfall etc. In addition, the corrosion rate of metals can be measured. Each climatic zone is characterized by its corrosion rate. This article presents the testing results to determine the corrosion rate of carbon steel, copper, aluminum and zinc in 12 districts characterizing different climate zones of Vietnam. Testing, evaluation, and classification of atmospheric corrosion were conducted in accordance with the standard ISO 9223. The results show that for all types of studied metals, their corrosion rates which are determined from climatic data are higher than the corrosion rates in reality, especially for carbon steel and aluminum. This difference is more visible in the rural areas.

Practical Study on the Corrosion Rates of Alloys (Aluminum, Medium Carbon Steel, Copper & Brass) Using Dissolved Ozone

Ozone is a strong oxidizing a gen, with a standard electrode potential of 2.07V.Oxidize materials, equipment a, surfaces wanted to clean. Ozone unfortunately, reacts with those materials and others leading to corrosion in those materials moreover those materials could lose their effectiveness. Because of multiple uses of Ozone, its effect on corrosion of Aluminum, Medium Carbon Steel, Copper & Brass in three different flow rates by weight losses method with benefits from linear fitting process was studied. The experimental shows that corrosion rates of Aluminum & Brass in three flow rates, decreasing with increasing the exposure time to corrosion, meanwhile the corrosion rates for Medium Carbon Steel & Copper decreasing only for (0.25 ft3/hr) and for another two flow rates (0.5 & 0.75 ft3/hr) the corrosion rates increasing with increasing the exposure time to corrosion, because of ozone gas flow rate positive& negative effected by forming oxide and hydroxide film which damage or not by increasing the corrosion intervals and ozone flow rates increasing. The average of total corrosion rates for the materials used in previous work increasing with increase the flow rate of Ozone in distilled water and the maximum value was (8.71×10-17MPY), meanwhile the minimum values was (4.08 ×10-17MPY).

Evaluation of the Corrosion Rate of Aluminum 6063 in Petrol, Kerosene and Water

The unparalleled combinations of properties of aluminum and its alloy makes aluminum one of the most versatile, economical, and attractive metallic materials for a broad range of uses. This study was carried out to evaluate the influence of kerosene, petrol and water on the corrosion performance of three samples of aluminum 6063 alloy (A and B sourced locally while sample C is an imported material). The corrosion rate was determined both by weight loss and Potentiostatics method, and the microstructure of the samples after five weeks of immersion also was examined with the aid of an optical microscope. Samples A, B and C were immersed in the media for five (5) weeks duration. The cumulative corrosion rate was measured at the end of each week. The average corrosion rates using the weight loss method for A in petrol, kerosene and distilled water were 3.100E-4, 4.905 E-4 and 6.205 E-4; for B were 4.367 E-4, 2.703 E-4 and 2.147 E-4; and those of C were 4.550 E-4, 2.257 E-4 and 1.633 E-4 respectively. Similarly, the average corrosion rate using Potentiostatics method of A in petrol, kerosene and distilled water were 0.586E-3, 0.643E-3 and 0.454E-3; for B were 0.206E-3, 0.197E-3 and 0.298E-3; and those of C were 0.183E-3, 0.232E-3 and 0.407E-3 respectively. The average result showed that Sample A had the highest corrosion rate. The media which corroded the samples the most was petrol.

EFFECT OF RATIO OF SURFACE AREA ON THE CORROSION RATE

Aluminum and steel are used to be a construction for a building outdoor panel. Aluminum and steel are connected by bolt and nut. An atmosphere due to a corrosion of the aluminum. The corrosion possibly to cause the hole diameter of bolt and nut to become larger. Thus the bolt and nut can not enough strong to hold the panel. The panel may collapse. The aim of the research is first to answer a question where does the corrosion starts. The second is to know the effect of ratio surface area of steel with aluminum on the corrosion rate of aluminum. The research is started to cut a steel and aluminum flat into variation surface areas. Next, the steel and aluminum are bolted as samples for corrosion test. The samples are divided into two groups. The group A was immersed in NaCl (10%) and the groups B was immersed in HCl 10%. The corrosion rate is calculated with loss weight method. The conclusions are as follow. The corrosion does not start from the bolt hole but from the edge of aluminum. Increasing the ratio of surface area (steel/aluminum) increases the corrosion rate of aluminum.

Evaluation of the Inhibitive Effect of African Marigold (Tagetes erecta L.) Flower Extracts on the Corrosion of Aluminium in Hydrochloric Acid

Corrosion inhibition of Aluminium coupon in acidic medium using flower extract of marigold (Tagetes erecta L) in 0.5M HCl solution was investigated using weight loss technique which is considered more informative than other laboratory methods. Aluminium sheets of purity 98.98%, each sheet was 0.1 cm in thickness and cut into coupons of dimension 6cm x 3cm and was decreased by washing with absolute ethanol, dried in acetone. These rectangular test coupons were totally immersed in the acid solution containing the various concentration of the inhibitor at the time intervals of 5-25 hours. The maximum values of the inhibition efficiency of 90.2%, 90.1%, and 90.1% were obtained at the concentration of 3.4ml, 4.5ml and 5.6ml for 5hours immersion time respectively. The corrosion rate was found to decrease tremendously and it was also observed that the inhibition efficiency (%) increased with an increase in the volume of the extracts. The corrosion inhibition is probably due to the adsorption f the phytochemical constituents of the extract on the metal surface and blocking its active sites by the phenomenon of chemicaladsorption. The study showed that the flower extract of Targets erecta L. in 0.5M HCl possesses inhibiting properties for reducing the corrosion rate of aluminium.

The controlling role of sodium and carbonate on the atmospheric corrosion rate of aluminum

Aluminum and aluminum alloys are widely used in many outdoor applications due to their inherent corrosion resistance attributed to the formation of a protective oxide layer. While corrosion rates are generally considered low for aluminum in many atmospheric environments, understanding of the corrosion performance over time is necessary to predict the cost, safety, and esthetics of these materials. The vast majority of the knowledgebase of atmospheric aluminum corrosion is built on environment–response relationships; often based on statistical correlation of corrosion rate data with atmospheric environmental conditions. However, there is still a limited mechanistic understanding of corrosion processes associated with this linkage. This lack in knowledge prevents interpretation and limits the extrapolation of these statistical datasets for prediction purposes. Here, the mechanistic dependence of aluminum corrosion rate on salt loading is explored through complimentary experimental and theoretical analysis relating corrosion rate to electrolyte chemistry, volume and corrosion products. From these results a reaction pathway is proposed for the atmospheric corrosion of aluminum that accounts for the governing effects of CO2 and salt loading on corrosion rate. This reaction pathway provides a new perspective that highlights the importance of the formation and growth of dawsonite (NaAlCO3(OH)2), and the subsequent gettering of sodium from the electrolyte leading to the stifling of corrosion kinetics. This study highlights the importance of accounting for the dynamic physical and chemical state of the electrolyte during corrosion in process models and measurement techniques to better understand and predict atmospheric corrosion behavior.

Synthesis of baicalin derivatives as eco-friendly green corrosion inhibitors for aluminum in hydrochloric acid solution

Three baicalin derivatives named methyl ester of baicalin (BM), ethyl ester of baicalin (BE), and n-propyl ester of baicalin (BP) were synthesized in the laboratory using the traditional Chinese medicinal herb Scutellaria baicalensis Georgi as raw material. The inhibition effect of the as-synthesized baicalin derivatives was investigated as eco-friendly green inhibitors on the corrosion of aluminum in 1.0M HCl solution by weight loss and various electrochemical techniques. Results show that the baicalin derivatives exhibit excellent performance as inhibitors for aluminum corrosion. The synthesized baicalin derivatives suppress both the anodic and cathodic process and the compounds behave as mixed-type corrosion inhibitors for aluminum in HCl solution. Also, results obtained indicate that compound BM is the best inhibitor and the effectiveness of these inhibitors decreases in the order of BM>BE>BP. The maximum inhibition efficiency obtained at 25°C using BM=0.9 g/l was ∼95%. The interpretation of the inhibition due to adsorption of the compounds on the aluminum surface is according to Langmuir adsorption isotherm. The free energy of adsorption for inhibition process was determined on the basis of Langmuir adsorption isotherm. Surface analyses were performed to establish the mechanism of corrosion inhibition of aluminum in acidic solution. The formation of the adsorbed baicalin-Al3+ complex on the metal surface led to slow down the corrosion rate of aluminum and improvement of the inhibition process.

Specific Features of the Contact Corrosion of Aluminum and Copper in NaCl Solutions

It is shown that the corrosion rates of aluminum and copper specimens in a 3% NaCl solution are 1.5–1.7 times higher than in a 0.1% NaCl solution. It is also discovered that the corrosion rate of copper in contact with aluminum placed in 3% NaCl is lower than for its individual specimens and, as the area of aluminum increases, decreases to zero. Thus, in particular, as the area of aluminum specimens (for a constant area of copper specimens) becomes 6.5 times larger, the corrosion rate of aluminum becomes 1.7 times higher. A discrepancy is discovered between the computed values of the rate of contact corrosion of aluminum for high values of the ratio of areas in the aluminum–copper couples and the experimental data. The polarization curves of aluminum in contact with copper placed in 0.1% NaCl are shifted to the region of less negative potentials and the ultimate diffusion and corrosion currents are greater by an order of magnitude than for the individual copper and aluminum specimens. It is established that the KORSOL inhibitor, which satisfactorily inhibits the rates of corrosion of copper and aluminum in tap water, practically fails to protects these metals, including the case of their contact, in 0.1% NaCl, whereas the TIS-4 inhibitor protects the metal by ~ 50–60%.

Activation of Al powder with NaCl-assisted milling for hydrogen generation

ABSTRACTHydrogen generation by the reaction of Al–NaCl mixtures with water was investigated over the 30–70°C temperature range. 5, 10, and 20 wt% of NaCl were added to Al powder and ground by planetary ball milling. The addition of NaCl activated the powders and prevented cold welding of Al powders during ball milling process. Smaller particle size and deformed microstructure accelerated the corrosion rate of aluminum with water. The results showed that 20 wt% NaCl, 12 h ball milling time, and 70°C reaction temperature effectively enhanced the hydrogen generation rate of the powders.

Effect of AlTi6 grain refiner on morphology, corrosion and mechanical properties of the commercial purity AA1050 aluminum alloy

Studying grain growth and the influences of grain refiners are important to control the mechanical properties and corrosion susceptibility of cast aluminum. Three different types of grain morphologies are possible; namely, columnar, twinned columnar, and equiaxed. In this study, commercial aluminum was melted at 750 °C in the presence of master alloy (AlTi6) with various addition levels (0.5–6 gMaster alloy /kgAl ). Inoculants in the form of master alloys were used to promote the formation of a fully equiaxed grain structure. The grain refiner's effect on the corrosion behavior of aluminum was investigated. An Energy Dispersive X-ray test was carried out to study chemical composition. The effect of AlTi6 on the grain size and distribution of equiaxed grains were investigated. Mechanical testing was performed. Rate of corrosion was carried out to investigate the effect of AlTi6 on aluminum grain size. EDX analysis showed a 99.29% Al level in the commercial purity aluminum alloys. Columnar and twinned columnar grains were successfully suppressed in the presence of 5–6 gAlTi6 /kgAl . Tensile test showed an increase in the yield strength. The corrosion rate of commercial aluminum increased from 3.942 mm/year to 4.537 mm/year in the presence of 5 gMaster alloy /kgAl . Corrosion current density was shown to increase from 0.3983 µ A/cm2 to 0.4584 µ A/cm2 .

Corrosive characteristics of bioethanol and gasoline blends for metals

Corrosive characteristics of lignocellulosic bioethanol on metals, such as mild steel, copper, and aluminum were studied by static immersion test at room temperature. Effect of metals on degradation of fuel properties, such as pHe, total acid number, acidity, density, viscosity, calorific value, flash point, and color changes were evaluated. Moreover, the transformation of water content and oxidation products in the fuel were investigated. Effect of fuel blends on corrosion rate, chemical structure of metals, and morphology of corrosion product were also examined. Results showed that the corrosion of metals in E50 (50% bioethanol and 50% gasoline) is high compared with E25 and E0. Moreover, degradation of fuel properties and compositional changes in E25 and E50 were high compared with E0. The corrosion rate of aluminum in E50 (0.216 mpy) was lower than copper (0.441 mpy) and mild steel (0.487 mpy). Moreover, the corrosion rate of aluminum in E25 (0.096 mpy) was also lower than copper (0.285 mpy) and mild steel (0.297 mpy). It was discovered that corrosion of materials and degradation of fuel properties were 2.4 times high in higher ethanol blends (above E25) compared with lower ethanol blends (up to E25). Copyright © 2016 John Wiley & Sons, Ltd.

Corrosion of Aluminum in Contact with Oxidized Titanium and Zirconium

We study the corrosion of alloys based on titanium, aluminum, zirconium, and iron in solutions of sodium chloride. The corrosion rate of aluminum significantly increases in contact with zirconium, titanium, and stainless steel. It is shown that the kinetics of aluminum corrosion is controlled by the cathodic reaction of reduction of molecular oxygen. It is also demonstrated that the corrosion rate of aluminum outside the contact zone is equal to the rate observed in contact with oxidized zirconium or titanium. The protective properties of oxide coatings on titanium and zirconium obtained by the method of microarc oxidation and high-temperature oxidation are investigated by the method of impedance spectroscopy.

The Influence of Sodium Molybdate on the Rate of Corrosion of Aluminum in Phosphoric(V) Acid

Corrosion rates of aluminum in phosphoric (V) acid solutions were determined gravimetrically in a presence of sodium molybdate which acts as an inhibitor. Inhibition efficiencies were calculated. The most effective corrosion inhibition was observed for 0.5 M H3PO4 and 100 mM of Na2MoO4. Since insoluble corrosion products precipitated onto specimens and influenced the determined corrosion rates, an analysis of a morphology of the specimens was performed by using a scanning electron microscope. The corrosion products are composed of Mo, P, Al and O. An Mo/P atomic ratio varied between 0.8 and 1.6 depending on the concentrations of phosphoric (V) acid and sodium molybdate. For three concentrations of H3PO4, the concentration ranges of sodium molybdate, where the gravimetric method may be applied were determined.

The corrosion rate of aluminium in the orthophosphoric acid solutions in the presence of sodium molybdate

The influence of the Na2MoO4 initial concentration on the corrosion rate of aluminium in the H3PO4 solution (0.5, 1, 2M) between 290 and 323K was studied using a gasometric technique. Inhibition efficiency was calculated. Depending on the initial concentration of Na2MoO4 the inhibition mechanism was either the adsorption of the inhibitor onto the surface of metal or the adsorption together with the formation of the conversion coatings. The solutions of 1M H3PO4, 50mM Na2MoO4 may be applied to determine the mass per unit area and thickness of anodic coatings.

NaBH4가수분해 반응기 소재로서 알루미늄 합금의 특성 연구

NaBH4 가수 분해용 경량반응기의 재질로서 알루미늄 합금을 검토하였다. 알루미늄은 알칼리에 용해되는데, NaBH4반응 용액중에 안정화제로 NaOH가 포함되어 있다. 알루미늄의 부식 속도를 낮추기 위해서 NaOH 농도를 낮추면 저장중에 NaBH4가 손실된다. 그래서 최적의 NaOH 농도를 결정할 때 알루미늄 부식과 NaBH4 안정화를 모두 고려해야한다. NaBH4 안정화와 알루미늄 부식속도는 수소발생속도에 의해 측정하였다. NaBH4 안정화는 20~50 oC에서 알루미늄 부식속도는 60~90 oC 온도에서 실험하였다. 알루미늄 부식과 NaBH4 안정화를 모두 고려한 최적의 NaOH농도는 0.30 wt% 였다. 알루미늄 합금 6061를 사용해 반응기 온도 80~90 oC에서 NaOH 0.3 wt%로 200분간 반응을 진행하였다.