Effect of Pre-Ageing Thermal Conditions on the Corrosion Properties of Antimony-Modified Al-Si-Mg Alloy

The purpose of this investigation was to evaluate the effect of pre-ageing thermal conditions on the corrosion properties of antimony-modified Al-Si-Mg alloy.The alloy was subjected to a Single Thermal Ageing Treatment; STAT (T6 temper-solution heat treatment and ageing) and Double thermal ageing treatment; DTAT (T7 temper- solution heat treatment and ageing for stabilization). These consist of solution heat treatment (SHT) at 540oC for 1hr, water quenched followed by an artificial ageing; DTAT and STAT. For the single thermal ageing treatment (STAT), quenched samples were aged at temperatures of 1800C for 2hrs, before cooling in air. In the double thermal ageing treatment (DTAT), quenched samples were pre-aged at a temperature of 90oC, 105oC and 120oC for 1- 5 hrs. This was followed by ageing at 180oC for 2hrs before cooling in air. The corrosion characteristic of the as-cast, Single Thermal Ageing Treatment (STAT) and Double Thermal Ageing Treatment (DTAT) were evaluated using weight loss and linear polarization techniques in a static 3.5%NaCl solution. From the results, the corrosion rate decreases with increasing pre-ageing time and temperatures. Equally, from the linear polarization data/curves, the corrosion rate of the treated alloy decreases at all ageing temperatures along with the ageing time. The Optical Microscope (OM) results of as-corroded samples revealed that the alloy suffers pitting/uniform corrosion. The corrosion behaviour of the DTAT samples in simulated seawater showed an excellent improvement in corrosion resistance than the as-cast and conventional STAT alloy.http://dx.doi.org/10.4314/njt.v34i4.

Chemical, mineralogical and petrological characterization of Gyaza iron ore deposit, Katsina State, Nigeria

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Mechanical properties and microstructural analysis of Al–Si–Mg/carbonized maize stalk waste particulate composites

AbstractThe mechanical properties and morphological analysis of Al–Si–Mg/carbonized maize stalk particulate composites was investigated. The compositions of the composite include a matrix of Al–Si–Mg and the carbonized maize stalk particulates as reinforcement ranging from 2% to 10% at an interval of 2%. Properties such as mechanical behaviour of the composites were examined and these include tensile strength, tensile modulus, hardness value, impact energy, percentage elongation and percentage reduction in area. Besides, the microstructures of the developed Al–Si–Mg/carbonized maize stalk particulate composites were investigated. The results of the microstructures of the composite show a uniform dispersion of the reinforcement along the grain boundaries of the alloy. The tensile strength and hardness values increase to 85.60N/mm2 and 24HRB at 8 and 10wt% of carbonized maize stalk respectively, but there is a slight decrease in the impact energy values, values of percentage elongation and percentage reduction in area as the reinforcement increases. From these results of investigation, we concluded that the carbonized reinforcing maize particulates can be used to enhance the properties of Al–Si–Mg alloy for engineering applications

Effect of load on the wear behaviour of polypropylene/carbonized bone ash particulate composite

The effect of applied load on the wear behaviour of polymer matrix composites produced using carbonized bone particles (CBp) as reinforcement has been studied. The addition of the CBp ranges from 5 to 20 wt% in the polypropylene matrix. The composites were produced by compounding and compressive moulding. The wear test was conducted by varying the applied load from 5 to 15 N. Microstructures of the worn surface were assessed with high resolution scanning electron microscopy (HRSEM/EDS). The wear rate increased with increases in applied load from 5 to 15 N and decreased with increasing in CBp from 0 to 15 wt%. The work has established that carbonized bone can be use in increasing the wear resistance of polypropylene composite

Development of Asbestos - Free Brake Pad Using Bagasse

Development of asbestos-free brake pad using bagasse was investigated with a view to replace the use of asbestos whose dust is carcinogenic. The bagasse were sieve into sieve grades of 100, 150, 250, 350 and 710µm. the sieve bagasse was used in production of brake pad in ratio of 70%bagasse-30%resin using compression moulding. The properties examined are microstructure analysis, hardness, compressive strength, density, flame resistance, water and oil absorption. The microstructure reveals uniform distribution of resin in the bagasse. The results obtained showed that the finer the sieve size the better the properties. The results obtained in this work were compared with that of commercial brake pad (asbestos based) and optimum formulation laboratory brake pad Palm Kernel Shell based (PKS), the results are in close agreement. Hence bagasse can be used in production of asbestos-free brake pad

Chemical and mineralogical characterization of Gidan Jaja iron ore, Zamfara State, Nigeria

The chemical and mineralogical characteristics of Gidan Jaja iron ore located in Zurmi Local Governmental Area of Zamfara State was carried out using X-ray Fluorescence (XRF) spectrometer, X-ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Optical Microscope. The XRF results obtained revealed that Gidan Jaja Iron ore has an average content of 73.79 % Fe2O3, 0.52 % MnO, 17.50 % TiO2, 0.11 % CaO, 0.50 % Cr2O3, 3.84 % SiO2, 0.43 % Al2O3, 0.034 % CuO, 0.02 % NiO, 0.46 % PbO, 2.76 % LOI. Phosphorus and Sulphur were below limit of detection. XRD analysis revealed that the ore contained 56 % Ilmenite, 34 % Magnetite and 10 % Spinel minerals. Petrographic study using polarized light revealed that the iron bearing minerals are predominantly Ilmenite and Magnetite, with minor amount of hematite, spinel and quartz. The results obtained from SEM analysis showed that the iron bearing minerals are separated from other minerals in the ore by smooth grain boundaries. The quality of the ore was compared with ores from other part of Nigeria, and based on the results obtained in this research work, Gidan Jaja iron ore can be classified as high grade, low silica, ilmenite iron ore. Finally combined results from chemical and mineralogical characterization of the iron ore deposit indicated that, the iron ore can be a source of iron ore for use in iron production.Keywords: Chemical, Mineralogical, Characterization, Gidan Jaja, Iron or

Coal mining and the environmental impact of Acid Mine Drainage(AMD): A review

In spite of the growing global initiatives towards achieving clean energy, coal remains a dominant source of electricity generation, a fuel for iron and steel production, an important entity among road construction materials and a commodity for foreign exchange earnings for many nations. Coal mining from old and active sites remains a source of an environmental problem described as acid mine drainage (AMD). AMD is produced when sulfide present in waste rocks or tailings in coal mines reacts with air and water in a microbes facilitated oxidation to form solutions with high acidity. The acids formed by these chemical and biological conditions further release heavy metals present in the host rock in concentrations higher than are acceptable by environmental standards (pb;0.01, Zn;5, Cu;2, Fe;0.3 mg/l as prescribed by WHO and Encyclopedia of Environmental Science,2000) such that soils, surface and underground waters are contaminated. Consequently, the human population which derives her livelihood in the mine zones, in form of crop production and fishing/modern aquaculture is endangered by terminal health diseases. This article aims at bringing forth, the urgent need to work towards achieving goal six of the United Nations Sustainable Development Goals, 2030 (SDGs-6) which is clean water and sanitation while enriching the knowledge repository of the environmental problem for the purpose of teaching, research, community services and policy making. An overview of AMD menace, variables which influence its formation, selected areas that have been impacted, and a brief analysis of its treatment cost have been discussed with a list of concluding remarks in the paper. Keywords: Coal, Mining, Environmental , AM

Inhibitive effect of Arachis hypogeae on the corrosion of mild steel in sulphuric acid solution

The corrosion assessment of mild steel in H2SO4-Arachis hypogeae natural oils have been studied using electrochemical technique. The surface morphology of as-corroded samples was assessed with scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS). The results revealed that corrosion rate of mild steel with Arachis hypogeae-H2SO4 environment decreased significantly. Results of the linear polarization indicate a higher potential value and inhibitor efficiency of 98.68, 86.87 and 97.10% at 100%v/v Arachis hypogeae with an increase in polarization resistance (Rp) and lower current density for the inhibited samples than the uninhibited mild steel. There exists some level of correlation in the corrosion efficiency between the methods used as criteria for the corrosion evaluation of mild steel/Arachis hypogeae in 2M H2SO4 solution

Effect of Avogadro natural oil on the corrosion inhibition of mild steel in hydrochloric acid solution

The inhibition action of Avogadro natural oil on corrosion of mild steel in one molar hydrochloric acid solution was investigated by gravimetric and potentiodynamic polarization techniques. The surface morphology of as-corroded samples was assessed with high resolution scanning transmission electron microscopy equipped with energy dispersive spectroscopy (HR-STEM/EDS). From the results, the presence of Avogadro natural oil in the metal–acidic interface decreased the corrosion rate with all the exposure times. The inhibition efficiency (%IE) increases with the concentration of the inhibitor considered. Results obtained from gravimetric measurements indicate that the natural oil exhibited higher efficiencies of 93.26 % after 384 h of exposure time and 98.26 % recorded in the potentiodynamic polarization method, both at 4.5 g/v inhibitor addition. Equally, results from the linear polarization indicated higher potential value with an increase in the polarization resistance (R p) and lower current density for the inhibited samples than the uninhibited mild steel sample. The inhibitive effect of this oil was explained in view of adsorption on the metal surface. The adsorption process follows the Langmuir adsorption isotherm

Effect of thermal ageing treatment on the mechanical properties of antimony-modified A356.0-type Al-Si-Mg alloy

Studies have been made on the mechanical properties upon thermal ageing of a sand cast antimony-modified A356-type Al-Si-Mg alloy. The produced alloy was solution heat treated at 540oC/1 h then subjected to thermal ageing treatment at 180oC for 1-5 h. There mechanical properties; Tensile properties, Hardness and Impact strength were used as criterion. From the results, the tensile properties and hardness increased with thermal ageing treatment. While the impact energy and elongation decreased upon ageing. The tensile properties of antimony-modified Al-Si-Mg alloy improved with ageing time and that the microstructures indicate spherodization of the silicon flakes to fine structures, which account for the improved propertie