Morphology and Properties of Zn-Al-TiO2 Composite on Mild Steel

The influence of TiO2 composite and dispersed pure Al particle on zinc alloy electrodeposited on mild steel was studied from chloride bath solution.Microstructural and mechanical properties of the alloy were investigated. The structure, surface morphology, and surface topography of the deposited alloys were characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM).In addition, hardness of the coated alloys was measured. It was found that the obtained Zn-Al-TiO2 alloyexhibited more preferred surface morphology and mechanical strength compared tothe substrate. The result shows the existence of interaction between TiO2 compounds and zinc alloy particulate. It also exhibited well bright dominate zinc coating on steel surface

Electrochemical Potential Monitoring of Corrosion and Inhibitors Protection of Mild Steel Embedded in Concrete in NaCl Solution

The corrosion and protection behaviour of mild steel embedded in concrete, and partially immersed in 3.5% sodium chloride solution, was studied in this investigation at ambient temperature by potential monitoring technique. The work was performed with a digital multimeter and a Cu/CuSO4 electrode (CSE) as the reference electrode. Extracts of pawpaw (carica papaya) leaves and sodium nitrite in different concentrations were separately and in combination, used as inhibitors. This paper reports the observed electrochemical response from the electrode potential monitoring of the embedded mild steel during the experiments. The results obtained, showed a reduction in the active corrosion reactions behaviour of the embedded mild steel in concrete admixed with different concentrations of sodium nitrite and the pawpaw leaves extracts thus indicating corrosion inhibition characteristic. The observed inhibition was attributed to the protective film provided on the steel’s surface in the concrete by the complex chemical compounds of the plant leaves’ extracts and the reaction of sodium nitrite with the alkaline environment of the concrete and its constituents. The combination of pawpaw extracts and the NaNO2 solution provided effective corrosion inhibition of the embedded steel by synergism. The 100% concentration of each of the inhibitors and when in combinations, exhibited the most effective corrosion inhibition performanc

Effect of Tobacco and Kola Tree Extracts on the Corrosion Inhibition of Mild Steel in Acid Chloride

Corrosion and inhibitor protection of mild steel specimens immersed in acid chloride solution was investigated at ambient temperature by gravimetric and potential monitoring methods. The electrode potential monitoring was performed using a digital voltmeter and a saturated calomel electrode (SCE) as the reference electrode. Extracts of kola plant and tobacco in different concentrations were used as ‘green’ inhibitors. This paper reports the results obtained from the weight loss method, calculated corrosion rates and the observed electrochemical response from the electrochemical potential monitoring of the mild steel during the experiments. A reduction in the active corrosion reactions behaviour of the mild steel test specimens in the strong acid chloride was obtained with the addition of different concentrations of the plants extracts. There was a drastic reduction in the weight loss and in the corrosion rate of the test samples. This behaviour was attributed to the protective film provided on the steel’s surface by the complex chemical constituents of the plants extracts. Effective protection of the mild steel was achieved in nearly all the extracts for the greater part of the experimental period. However, the most effective results were obtained from the tobacco extract and also from the extract of kola leaf

Environmental Surface Degradation of Galvanised and Mild Steels in Cattle and Poultry Wastes and Urea Solution

An investigation of the corrosive properties of cattle and poultry dung/urine slurries and urea solution and by extension, the corrosion resistance of galvanised and mild steels in these respective test media was performed by the weight loss method. The results showed corrosive surface degradation of galvanised steel and extensive corrosion of the mild steel test specimens by the corrosive constituents of the various test media. The corrosive constituents in the slurries are believed to be urea, uric acid,ammonia and ammonium salts, naturally excreted chloride (common salt), carbon-dioxide and sulphate reducing and sulphur oxidizing bacteria. The galvanised steel is found to be more corrosion resistant than the mild steel. The cattle dung/urine slurry was found to be the most aggressive of the test media and the poultry dung/urine slurry, the least corrosive medium

Effect of Anode and Size Variations on the Cathodic Protection of Mild Steel in Sea Water and Sulphuric Acid

The performance of different sizes of zinc, and aluminium galvanic anodes on the cathodic protection of mild steel in seawater and 0.2 M sulphuric acid was evaluated at ambient temperature. The magnitude of corrosion protection by the galvanic anodes was observed by weight loss method,corrosion rate calculation and potential measurement technique. It was observed that the aluminium anodes proved more effective as sacrificial anode for mild steel in seawater environment. In sulphuric acid environment, the zinc anode gave a more protective performance than aluminium anode. Potential measurement results obtained were found to correspond with the results obtained from weight loss method. For both environments, the effects of a varying cross-sectional area and the anode material on the cathodic protection of mild steel were examine

PLANTS EXTRACTS CORROSION INHIBITION OF ALUMINIUM ALLOY IN H2SO4

Effects of tobacco (Nicotiana) and Kola tree (Cola acuminata) extracts on the corrosion inhibition of an aluminium alloy 2S (1200) grade specimens immersed in 0.5M sulphuric acid was investigated at ambient temperature by gravimetric and metallographic methods. Extracts of kola plant and tobacco in different concentrations were used as ‘green’ inhibitors. This paper reports the results obtained from the weight loss method, calculated corrosion rates, inhibitor efficiencies and the optical microscopy metallographic observations. Addition of different concentrations of the plants extracts gave clear reduction in weight loss and in the corrosion rate of the test samples. This apparent corrosion inhibition was associated with the protective film provided on the aluminium alloy’s surface by the complex chemical constituents of the plants extracts

Effect of Cola Acuminata and Camellia Sinensis Mixed Extracts on the Corrosion Inhibition of Mild Steel in 0.5M Sulphuric Acid

The corrosion inhibition effect of extracts of kola plant (cola acuminata) and green tea (camellia sinensis) in mixed form on the protection of mild steel specimens immersed in sulphuric acid solution was studied at ambient temperature by gravimetric and potential monitoring methods. The electrode potential monitoring was performed using a digital voltmeter and a saturated calomel electrode (SCE) as the reference electrode. Extracts of kola plant and green tea in different concentrations and combinations were used as ‘green’ inhibitors. There was significant reduction in the weight loss and in the corrosion rate of the test samples, particularly at the added extracts concentration of 100% and also at the concentrations of 50 and 25%. Some very good inhibitor efficiency values were obtained which suggested good corrosion inhibition performance of the added extracts at the concentrations used. Potential measurement values recorded showed a reduction in active corrosion reactions for all the combinations of the extracts. This behavior was attributed to the protective film provided on the steel’s surface by the complex chemical constituents of the plants extracts. The best corrosion inhibition performance for mild steel was obtained using the combined extracts of kola leaf and green tea at100% concentration. The combination of kola leaf, kola nut and green tea at the same concentration was also effective in corrosion inhibition performanc

Levels of awareness and concentrations of heavy metals in the blood of electronic waste scavengers in Nigeria

Background - Electronic waste (e-waste) contains both valuable and hazardous materials. E-waste scavengers specialize in the collection and crude recycling of waste electronics to retrieve valuable metals, which are then sold. These activities provide an income for scavengers, but also expose them to toxic heavy metals such as lead (Pb) and copper (Cu). Objectives - The aim of the present study was to investigate the level of awareness and concentrations of heavy metals (Pb, Cu, zinc (Zn) and manganese (Mn)) in the blood levels of e-waste scavengers at Jakande dumpsite, Alaba International Market, Lagos, Nigeria. Methods - Material and data were collected by empirical survey with the use of a questionnaire to obtain information from e-waste scavengers. Blood samples of the scavengers in the present study (30 adult males exposed to recycling processes) were collected and concentrations of heavy metals were determined through acid digestion and the use of an atomic absorption spectrophotometer (AGILENT 55B AA, 2010). Results - The geometric means of blood levels of Pb, Cu, Zn and Mn were 11.0, 33.85, 126.15 and 19.38 µg / dL, respectively. High concentrations of Pb and Mn (11.0 and 19.38 µg / dL) were found in the blood samples, while Zn and Cu (126.15 and 33.85 µg / dL) showed low concentrations. The maximum blood level of lead (BPb) (24.0 µg / dL) was extremely high compared to the maximum BPb of occupationally exposed males. Statistical analysis of the questionnaires showed that all of the respondents were male, and more than half (56.7%) were between 21-30 years of age and had been involved in recycling of e-waste for 1-5 years. The results showed that 83% of the respondents were aware that hazardous fractions in e-waste require special treatment, while 76.7% were aware of the possible negative impact on their health. Conclusions - Lack of education, poverty and lack of effective enforcement of e-waste management and regulations are the major contributors to the current situation and thus scavengers carry on with their activities unhindered. The authors recommend the use of protective clothing, sensitization visits and awareness campaigns on the safe disposal of hazardous components

Effect of Saccharum officinarum Juice Extract Additive on the Electrodeposition of Zinc on Mild Steel in Acid Chloride Solution

Experimental investigations have been performed to examine the electrodeposition of zinc on mild steel in acid chloride solution using as additive different concentrations of saccharum officinarum (sugarcane) juice extracts. The experiments were performed under different plating time, different additive concentrations and fixed pH conditions. Zinc electrodeposition on mild steel was performed using a DC – supply at defined operating parameters. The surface of the plated steel was examined using scanning electron microscopy (SEM); and Energy Dispersive Spectroscopy (EDS) for surface elemental composition analysis. Different surface characteristics were obtained depending upon the concentration of the additive and the plating time. The corrosion resistance of the plated surface was also determined by gravimetric method. The quality of electrodeposition of zinc was good as indicated by the plated surface microstructural morpholog

Inhibition effect of potassium dichromate on the corrosion protection of mild steel reinforcement in concrete

The inhibition of potassium dichromate on the corrosion protection of mild steel embedded in concrete and partially immersed in sulphuric acid and sodium chloride environments was evaluated at ambient temperatures. The experiments were performed using electrochemical potential monitoring method. Varying quantities of the inhibitor was used. In the NaCl test medium, the effectiveness of the inhibitor improved as higher concentration was used. The best inhibition was achieved in the reinforced concrete sample admixed with 9 g potassium dichromate. Steel-reinforced concrete sample admixed with 3 and 9 g potassium dichromate inhibitor had the highest improvement in compressive strength. The potassium dichromate inhibitor was most effective amongst other inhibitor concentrations used when 7.5 g was admixed with the sample in the H2SO4 medium. The sulphuric acid medium had a deleterious effect on the strength of concrete test specimens