Development and Characterization of PA 450 and PA 3282 Epoxy Coatings as Anti-Corrosion Materials for Offshore Applications.

The optimization of two different types of hardeners, namely polyaminoamine adduct (Aradur 450 BD) and polyamidoamine adduct (Aradur 3282 BD), with diglycidyle ether of bisphenol-A (DGEBA) epoxy resin was carried out. Three different stoichiometries of PA 450 to the epoxy resin to fabricate E-0, E-1, and E-2 coating samples and the other three of PA 3282 to the epoxy resin to fabricate F-0, F-1, and F-2 coating samples were coated on mild steel panels. All coated samples were characterized by scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), and nanoindentation techniques. The electrochemical corrosion behavior of the fabricated coatings was investigated using electrochemical impedance spectroscopy (EIS) after various exposures in the climatic conditions in 3.5% NaCl solutions. It was found that the coatings possess almost identical thermal and mechanical properties. Moreover, the E-1 coating shows better corrosion resistance compared to E-0 and E-2 coatings. On the other hand, the F-1 coating was the most effective in significantly improving corrosion resistance. Overall, the addition of PA 450 and PA 3282 to some stoichiometries improves the corrosion resistance of the fabricated coatings.

Alloying Elements Effects on Electrical Conductivity and Mechanical Properties of Newly Fabricated Al Based Alloys Produced by Conventional Casting Process.

The present investigation deals with a comprehensive study on the production of aluminum based alloys with the incorporation of different alloying elements and their effect on its electrical conductivity and mechanical properties. Casting of pure aluminum with different concentration and combinations of alloying additives such as cupper (Cu), magnesium (Mg) and silver (Ag) were carried out using a graphite crucible. The as-cast microstructure was modified by hot rolling followed by different heat-treated conditions viz., annealing, normalizing, quenching, and age hardening. The mechanical properties and electrical conductivity of the produced heat-treated alloys sheets under various processing conditions were carried out using tensile testing, hardness, and electrical resistivity measurements. It was found that by increasing the alloying elements content, yield strength results increased significantly by more than 250% and 500% for the as rolled and 8 h aged Al-Cu-Mg alloy, respectively. On the other hand, the electrical conductivity reduces slightly with -14.6% and -16.57% for the as rolled and 8 h aged of the same Al-Cu-Mg alloy, respectively.