RESUMEN
In this study, a silver nanoparticle anchored transparent tape sensor was used to detect 1,4-bis(2-aminoethyl)piperazine functionalized GO (AEP-GO) adsorbed on carbon steel surface utilizing the surface-enhanced Raman scattering (SERS) technique. SERS detection enabled the extreme amplification of Raman signals emitted by inhibitor molecules in order to describe their adsorption behavior on metallic/alloy surfaces. The strong corrosion inhibition performance of AEP-GO against carbon steel corrosion in 15 % HCl solution was proven by weight loss, electrochemical measurements and surface characterization techniques in a previous study. The SERS analysis showed the Raman peaks intensity of AEP-GO on the carbon surface gradually increases with increasing AEP-GO concentration. The increasing intensity with concentration correlated well with the previously reported weight loss and electrochemical results. DFT calculation was also carried out to understand the nature of interaction between the adsorbed AEP-GO molecules and the silver nanoparticles. The AEP-GO_Ag adduct's optimized structure reveals the silver metals approached the oxygen atom at the GO epoxy group in AEP-GO rather than the oxygen atoms at the carbonyl and hydroxyl groups. With no restrictions on substrate materials, the fabricated SERS sensor created in this study can be employed as a versatile sensor to characterize corrosion adsorption processes on metal surfaces.
RESUMEN
Friction stir processing (FSP) technology has received reasonable attention in the past two decades to process a wide range of materials such as aluminum, magnesium, titanium, steel, and superalloys. Due to its thermomechanical processing nature, FSP is used to alter grain structure and enhance mechanical and corrosion behavior in a wide range of steels. The refinement in grains and phase transformations achieved in steel after FSP affects hardness, tensile properties, fracture toughness, fatigue crack propagation rate, wear resistance, and corrosion resistance. A number of review papers are available on friction stir welding (FSW) or FSP of nonferrous alloys. In this article, a comprehensive literature review on the FSP/FSW of different types of steels is summarized. Specifically, the influence of friction stir processing parameters such as advancing speed, rotational speed, tool material, etc., on steels' performance is discussed along with assessment methodologies and recommendations.
RESUMEN
The possibility of utilizing dextran as a green corrosion inhibitor for steel in strong acid environment was explore using weight loss, electrochemical (electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), potentiodynamic polarization (PDP), and linear polarization (LPR)) supported with surface analysis via scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques. The effect of molecular weight, temperature, and modification on the inhibition efficiency of dextran was also studied. Results from all the applied techniques reveal that dextran exhibit moderate anticorrosion property toward St37-2 steel dissolution in 15% H2SO4 solution. Dextran with molecular weight of 100â¯000-200â¯000 g/mol (Dex 1) exhibited the highest inhibition efficiency of 51.38% at 25 °C. Based on PDP results, dextran behaved as a mixed type corrosion inhibitor. Inhibition efficiency of dextran varies inversely with molecular weight but directly with temperature. Two modification approaches, namely incorporation of silver nanoparticles (AgNPs) into dextran matrices and combination with 1 mM KI were adopted to enhance the inhibition efficiency of dextran and the approaches proved effective. The protective capability of Dex 1 has been upgraded from 51.38% to 86.82% by infusion of AgNPs and to 94.21% by combination with KI at 25 °C. Results from the study on the effect of temperature reveals that Dex 1 + KI mixture could synergistically offer 99.4% protection to St37-2 steel in 15% H2SO4 environment at 60 °C. Surface analysis results confirm the presence of additives molecules on the studied metal surface. XPS results disclose that AgNPs are in oxide form while iodide ions are in the form of triiodide and pentaiodide ions on the metal surface. Modified dextran is a promising candidate for application as corrosion inhibitor in acid induced corrosive environment.