Materials and Corrosion-werkstoffe Und Korrosion最新文献

This study investigated the effects of zinc addition, homogenization treatment, and thermomechanical processing via hot extrusion on the microstructure, corrosion behavior, and mechanical properties of biodegradable Mg–0.5Zr–0.5Ca alloy. Zinc alloying not only resulted in the formation of Ca₂Mg₆Zn₃ and Mg₇Zn₃ compounds, but also reduced the grain size up to 4.5 times in the as-cast condition, which improved the mechanical properties. Immersion tests in the simulated body fluid (SBF) solution at 37°C showed that a Zn content higher than 1 wt.% significantly improved corrosion resistance and reduced the corrosion rate to about five times smaller than the base alloy. While the extrusion process induced a remarkable grain refinement via dynamic recrystallization (DRX) and improved the strength-ductility balance, it had a detrimental effect on the corrosion resistance due to the higher volume fraction of the grain boundaries. On the other hand, the homogenization treatment improved the mechanical properties and reduced the weight loss during immersion tests by dissolving secondary phases, increasing the solute Zn content, and formation of hydroxyapatite Ca₁₀(PO₄)₆(OH)₂ film.

This work dealt with the evaluation of the effect of intermetallic particles in tin alloy on the localized corrosion of organ pipes. Typical intermetallic phases that occur in tin alloy of organ pipes (Cu₆Sn₅, FeSn₂) were prepared. Together with tin, these intermetallic alloys were studied in an environment of artificial rainwater and an aggressive wet film from a church environment (containing acetate) to determine electrochemical parameters (free corrosion potential, polarization resistance, and Tafel slopes). These data were then used as input for the numerical simulation of the function of galvanic microcells in the alloy structure. The results show a local increase in corrosion attack up to hundreds of percent.

Pure magnesium and magnesium alloys exhibit inadequate corrosion resistance inside the human body. Consequently, surface modification through texturing of AZ31 Mg alloy utilizing a pulsed fiber laser was performed. Laser texturing was conducted at a low power of 18 W with scanning speeds of 40 and 70 mm/s. The corrosion behavior of samples in simulated body fluid (SBF) was assessed using electrochemical techniques. SEM and XRD evaluated the impact of laser texturing on phase and microstructural evolution. The investigation indicated the development of the Mg₁₇Al₁₂ phase at the melted region in laser-processed samples. The evolution of this distinctive microstructure during laser processing demonstrated an improvement in corrosion resistance. The improvement was more pronounced at a scanning speed of 70 mm/s compared to 40 mm/s, with the corrosion rate in mm per year decreasing from 47.1 (as-received) to 4.5 at 70 mm/s and to 10.2 at 40 mm/s. The significant enhancement at 70 mm/s compared to 40 mm/s can be attributed to the shallower texturing process at 70 mm/s, evidenced by the lower roughness and greater surface microhardness observed at this speed.

In this article, dry and wet alternating cycle corrosion scenarios were simulated by accelerated corrosion tests under 1.0 × 10⁻²mol/L NaHSO₃ + 0.1 mol/L NaCl corrosion conditions. Field emission electron microprobe, X-ray diffraction, Raman spectroscopy and electrochemical testing were utilized to study the effect of Al element on the corrosion resistance of weathering steel. Using Materials Studio software, calculate that the addition of Al element will be uniformly distributed in the rust layer with lower binding energy (such as aluminum oxide or doped with other oxides). The synergistic effect of Al and Cr not only produces more stable FeAl₂O₁ in the early stage of corrosion, slowing down the corrosion rate, but also promotes the formation of α−(Fe_1−xCr_x) OOH and the transformation of γ-FeOOH, refining the grain size of α-FeOOH and enhancing its resistance to external corrosion factors.

Regulating the dissolution performance of soluble fracturing tools based on different actual operating conditions of oil and gas wells is of great significance for ensuring the smooth progress of fracturing processes. In response to the current evaluation of the dissolution rate of soluble downhole tool materials, immersion tests and electrochemical measurements under non-stress conditions are usually used, which cannot accurately predict the dissolution rate of soluble downhole tools under stress. Therefore, this paper evaluated the dissolution rate and maximum pit depth of microporous copper coating samples (CPS) in simulated formation water when the loading stress is 0% σ_s, 50% σ_s and 100% σ_s by using a three-point bending fixture, and its dynamic potential polarization curve (PDP), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry curve (CV) were tested. The results show that the uniform corrosion rate and maximum pit depth of CPS increase with the increase of loading stress. When the loading stress is 100% σ_s, both the uniform corrosion rate and the maximum pit depth increased significantly.