Corrosion Science最新文献

The role of electrode potential in CaCO₃ scaling behavior and kinetics on carbon steel and stainless steel surfaces is investigated through electrochemical tests, surface characterization, and numerical modeling. Under cathodic conditions, calcite is the dominant CaCO₃ polymorph, its lateral growth on steel surfaces follows exponential kinetics. However, under gradually promoted corrosion conditions of carbon steel, the presence of corrosion products induces more aragonite deposition and inhibits the lateral growth of CaCO₃ scale, gradually evolving from exponential to linear kinetics. This work provides further insight into how the cathodic and anodic reactions of steel corrosion respectively promote and inhibit CaCO₃ scaling.

The interdiffusion mechanism between EB-PVD deposited CoCrAlY coating and superalloy substrate under high-temperature oxidation atmosphere in actual gas turbines was investigated both experimentally and through thermodynamics and kinetics simulation. The interdiffusion behavior differs at different regions of blade due to the different service temperatures. The elemental interdiffusion and phase transformation behavior were investigated and discussed. Needle-like topologically close-packed phase and σ-CrCoNi phase have precipitated within the secondary reaction zone due to the γ→γ’ transition and the uphill diffusion of Cr, W, and Mo. Decreasing the Co content in the MCrAlY bond-coat can inhibit the interdiffusion behavior to a certain extent.

Phosphogypsum-based cold bonded aggregates (PCBAs), as incorporates excessive soluble sulfate, potentially induce Internal Sulfate Attack (ISA) corrosion to OPC, which severely constrains its utilization and advancement. This work applies consecutive pelletization using pozzolanic layerings (fly ash (FA) and phosphorus slag (PS) basis) for surface modification. The basic, exterior hydration and microstructure properties of PCBAs, as well as the interfacial corrosions of PCBAs-OPC, are investigated via XRD, TG-DTG, X-CT, SEM-EDS, μ-XRD, and nanoindentation technologies. Results indicate the FA and PS layerings block sulfate leaching by 15–30%. When blended with OPC, these layerings capture releasable sulfate within PCBAs exterior via interfacial hydration that also depletes portlandite to generate tighter ITZ. Therefore, the reactive layerings effectively alleviate ISA corrosion via in-front blockage and back-end reaction, as supported by reduced sulfate ingress within 30–40 μm, less degradation products (ettringite and gypsum) formation, and improved hardness of vicinity OPC. The FA-based layering performs slightly poorer due to its lower density causing inefficient consolidation of PCBAs. Consequently in macroscopic, the ISA-inducing fissures of concrete surface are diminished, followed by improved 90-d compressive strength from 36.43 MPa to optimally 48.38 MPa. This study elucidates the rich-gypsum aggregates-type ISA corrosion mechanisms to OPC and proposes an instructive solution using pozzolanic layerings.

The biodegradation of Fe is severely limited due to barrier of biodegradation products. Herein, NaCl was introduced into Fe matrix and results demonstrated that NaCl significantly accelerated biodegradation rate of Fe. It was ascribed that (i) NaCl in Fe matrix initially dissolved to produce biodegradation active sites, (ii) Cl^- with small ionic radii invaded the biodegradation product layer, and (iii) abundant Cl^- greatly promoted the anode process of Fe biodegradation. Additionally, Fe-NaCl biocomposites also exhibited favorite cytocompatibility. These results demonstrated great potential of NaCl in accelerating the persistent biodegradation of Fe for load-bearing implants.

Ti6Al4V biomedical plates were fabricated by Laser Powder Bed Fusion using different process parameters. A slight influence of the laser energy density on mechanical properties and microstructure was revealed. Chemical etching allowed to make the surface of 3D samples uniform removing also spheres of unfused material. After etching some samples were anodized in calcium acetate and β-glycerolphosphate containing solution to grow a Ca and P containing porous TiO₂ layers. The chemical etching improved the corrosion resistance of the alloy in simulated body fluid, while only after anodizing the alloys resulted to be corrosion resistant under inflammatory and severe inflammatory conditions.

A high-throughput screening method is developed for rapid evaluation of corrosion inhibitors. By employing a fluorometric technique, this method quickly assesses the concentration of iron ions converted from corrosion products in the reaction pool to rapidly evaluate the corrosion inhibition performance of amino acid and surfactants. Utilizing this high-throughput screening platform, the corrosion inhibition effects of L-cysteine mixed with quaternary ammonium salts of different alkyl chain length were evaluated, and their optimal mixing ratios were determined. Through corrosion experiments and molecular simulations, the synergistic mechanisms of the inhibitor mixtures are revealed.

This work reports the mechanism of corrosion resistance enhancement of 316 L stainless steel after Te-RE alloying. The individual MnS inclusions are replaced by composite inclusions, resulting in a reduced risk of pitting corrosion. The decrease of inclusion amount and Volta potential difference between inclusion and matrix induced by the addition of Te/La promoted the stability of the inclusions and lessened the active sites for pitting corrosion. TeO₂ formed in the passive film with Te treatment could be easily reduced by Cr and Mo, and resulting in a significant increasing of MoO₂ and Cr₂O₃ content in the passive film. This enhanced the stability of the passive film. Te and RE exhibited a synergistic effect on the increase of Cr and Mo in the passive film, resulting in a further improvement of the passive film. However, RE could not exist in the passive film stably due to its poor thermodynamic stability of the rare earth oxides, and only acted as a bridge for the formation of Cr and Mo oxides.