Performance Evaluation Effect of Nb2O5 Particulate on the Microstructural, Wear and Anti-corrosion Resistance of Zn–Nb2O5 Coatings on Mild Steel for Marine Application

In this study, we developed Zn–Nb2O5 composite coatings from sulfate bath for wear and corrosion performance on mild steel by electrodeposition technique. The effect of Nb2O5 particulate on the Zn–Nb2O5 properties was investigated. The particle volume fraction was varied within between 10 and 20 wt%. The structural properties of the composite coatings were characterized using scanning electron microscope equipped with energy-dispersive spectrometer. The hardness and wear of the composite coating were measured with diamond base microhardness indenter tester and sliding CETR reciprocating wear testers, respectively. The corrosion properties were examined in 3.65% NaCl using AUTOLAB 101 Metrohm potentiostat–galvanostat with linear polarization technique. The results showed that average hardness value of 192.6 and 200.6 HV and passivation potential of 4.39E?08 and 5.30E?08(X) were obtained for the 10–20 wt% Nb2O5 particulate on the Zn–Nb2O5 coatings. The wear performance improves by 63.4% as against the control sample. In all, this study established that up to 20 wt% of Nb2O5 in Zn–Nb2O5 composite coating significant corrosion, wear and microhardness propagation resistance of mild steel was attained

Structural and properties of Zn-Al2O3-SiC nano-composite coatings by direct electrolytic process

In this paper, Zn-SiC and Zn-Al2O3-SiC composite coating were fabricated by electrodeposition technique from sulfates bath. The resulting composite coating was carried out by adding Al2O3/SiC particulate to a zinc-containing bath. The properties of the composite coating were investigated by SEM equipped with EDS, XRD, and AFM. The electrochemical behavior of the coating alloy was evaluated in 3.65 % NaCl with linear polarization technique and mechanically examined by durascan microhardness tester. The morphology of the thermal treated coatings at 400 °C in 6 h was viewed with high optical microscope (OPM). The results show hardness, thermal stability, and anti-corrosion properties of Zn-Al2O3-SiC were improved significantly as against Zn- SiC coating matrixes. This was attributed to dispersive strengthening effect and grain induced effort of Al2O3/SiC particulate. The decrease in corrosion and thermal stability at 15 g/L of SiC concentration may be as a result of agglomeration and the superimposed particle in the plating bath

Performance environnementale et economique dans la production de la grande morelle (Solanum macrocarpon) au Sud du Benin : Une evaluation des efficacites technique, allocative, economique

L’objectif de cette étude est d’analyser les efficacités technique, allocative et économique dans la production de la grande morelle. Pour cela, une  étude descriptive et analytique a été réalisée sur un échantillon de 126 maraîchers des sites de production de Houéyiho, de Sèmè-Kpodji et de  Ouidah au sud du Bénin. Les efficacités technique et économique ont été estimées respectivement à l’aide des modèles frontières stochastiques translogarithmique et fonction de coût dual avec la spécification Cobb-Douglas. Le modèle de régression tobit a été utilisé afin d’identifier les facteurs déterminants les efficacités des producteurs. Les résultats obtenus montrent que les facteurs main-d’oeuvre et engrais chimique sont sur-utilisés, ce qui entraîne des inefficacités dans la production. Les efficacités technique, allocative et économique sont respectivement en moyenne de 0,689 ; 0,882 et de 0,607. L’âge du producteur, la superficie emblavée, la contribution de la grande morelle dans le revenu, le niveau d’instruction et la formation technique sont les principaux déterminants des efficacités technique, allocative et économique des producteurs de la grande morelle. Sur la base des résultats obtenus, il importe d’améliorer l’efficacité des producteurs et augmenter ainsi leur profit par la recherche de moyens de lutte efficace et le renforcement de l’encadrement technique des producteurs. Mots clés : efficacités, frontières stochastiques, fonctions translog, fonction Cobb-Douglas, Solanum macrocarpon. English title: Environmental and economic performance in the production of the great nightshade (<i>Solanum Macrocarpon</i>) in southern Benin: An assessment of technical, allocative and economic efficiencies The objective of this study is to analyse the technical, allocative and economic efficiencies in the production of Solanum macrocarpon in Southern-Benin. For this purpose, a descriptive and analytical study was conducted among 126 Solanum macrocarpon growers in Cotonou, Sèmè-kpodji and Ouidah. The technical and economic efficiencies were estimated respectively using translogarithmic stochastic frontier models and dual cost function with the Cobb-Douglas specification. The Tobit regression model was used to identify the determinants of producers efficiencies. The results show that labor and chemical fertilizers are overused, leading to inefficiencies in production. The averages of technical, allocative and economic efficiencies are 0.689; 0.882 and 0.607 respectively. The age of the producer, the surface grown, the contribution of solanum in the income, the educational level and the training in farming are the principal determinants of the technical, allocative and economic efficiencies of the solanum’s producers. On the basis of result obtained, it is important to improve the efficiency of the producers and thus to increase their profit by the search for effective means of pest control and the reinforcement of producer’s technical framing. Key words: efficiency, stochastic frontier analysis, translog function, Cobb-Douglas function, Solanum macrocarpon

Response evaluation of AA8011 with nano ZrB2inclusion formultifunctional applications: Considering its thermal, electrical, andcorrosion properties

Researches have shown severally that AA8011 alloy is limited in its multifunctional applicationsnotwithstanding its intrinsic properties. Nevertheless, these properties can be improved by compli-menting with high-grade reinforcement that have better Performance characteristics. In this investiga-tion, AA8011 properties are improved by ZrB2inclusion through a two-step stir casting process toenhance the thermal and corrosion resistance without significantly affecting the electrical properties.The thermal behaviour was analyzed using a thermogravimetric analyzer (TGA) and differential thermalanalyzer (DTA), the corrosion response was studied with auto lab potentiodynamic polarization in 3.5%NaCl, the surface degradation after corrosion was observed with scanning electron microscope (SEM),and the electrical performance was carried out on the four-point probe meter. From the experiments, adecrease in the composite mass loss; improved melting temperature of about 674.4ᵒC in the presence ofZrB2addition as a function of the temperature rise was achieved by TGA and DTA respectively. The highcorrosion resistance of 7831.7Uand low corrosion rate of 0.5017 mm/yr at AA8011-20 wt% ZrB2wasobtained, this was characterized by little or no visible pitting corrosion as revealed by SEM. Theenhancement of the thermal stability and the improvement of the corrosion resistance prowess ofAA8011 without an obvious compromise on its electrical behaviour is an indication that AA8011-ZrB2composite is a novel composite material for multifunctional application mostly where improved aluminium alloys are require

Nanoparticle Dispersion, Microstructure and Thermal Effect of Multi-doped ZrO2/SiC from Sulphate Induced Electrolyte

Effort to improve the hardness and thermal resilient properties of coating for advanced engineering applications has necessitated this study. Zn sulphate electrolyte was induced with ZrO2-SiC composite particulate at varied current density of 1.5 and 2.0 A/cm2 for 10 minutes. The incorporated composite particles of ZrO2/SiC were varied in other to examine their mechanical responses on zinc electrolyte. The coated films were characterised with scanning electron microscope with attached electron dispersion spectroscopy (SEM/EDS) and atomic force microscopy (AFM). The micro-hardness properties of the coated and thermal aged alloy were determined with high diamond micro-hardness tester. The anti-corrosion progression was examined using linear polarization technique in 3.65% NaCl. From the results, the incorporation of the composite matrix was found to impact significantly on the surface and microhardness properties. The co-deposition of composite submicron on the zinc electrolyte revealed that homogenous grain structure was obtained.To this end, a boost in the performance characteristics was attained due to effective co-deposition parameters in the electrolyte

Review of metal protection techniques and application of drugs as corrosion inhibitors on metals

The inability of metals to resist degradation as a result of corrosion remains a unique global problem that depend on different metals for daily operations. Therefore, knowing the appropriate method to use is a key to ameliorate corrosion effect on metals. Green inhibitors serve as a modern, cheaper and environmentally favorable method to retard the effects of corrosion. Drugs are corrosion inhibitors which can reduce the action of corrosion without being hazardous to the environment as they are synthesized from natural products. The review studies the metal protection techniques and the use of drug as corrosion inhibitors. The importance of copper as a useful metal as good corrosion resistance due to inherent properties alongside its malleability was also discussed