The present study investigated a new configuration of friction stir welded joints from two aluminum alloys. Dissimilar welds AA6082/AA1350 were examined, whereas, for AA1350, two states were investigated—coarse-grained (CG) and ultrafine-grained (UFG). Changes in the mechanical and electrochemical properties regarding the microstructure evolution across the welds were discussed. The average grain size in the stir zone (SZ) for all materials equaled 4 to 5 µm with a fraction of high-angle grain boundaries of about 77 pct, indicating the occurrence of continuous dynamic recrystallization. Changes in the microhardness across the welds were connected with differences in grain size (AA1350) and dissolution of β″ precipitates in the SZ of AA6082. As a result, the tensile strength of the welds decreased compared to base materials AA6082 and AA1350 UFG; however, there was an increase when compared to the base material AA1350 CG. Electrochemical experiments revealed that pitting corrosion occurred for AA1350, while for AA6082, it was a combination of pitting and intergranular corrosion. The depth of corrosion attack was higher for AA1350, with a maximum value of ~ 70 µm for base materials, while in the SZ, a depth decreased to 50 µm. For the AA6082, the maximum depth was measured in the SZ and did not exceed 30 µm.

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Creating durable, eco-friendly coatings for long-term corrosion protection requires innovative strategies to streamline design and development processes, conserve resources, and decrease maintenance costs. In this pursuit, machine learning emerges as a promising catalyst, despite the challenges presented by the scarcity of high-quality datasets in the field of corrosion inhibition research. To address this obstacle, we have created an extensive electrochemical library of around 80 inhibitor candidates. The electrochemical behaviour of inhibitor-exposed AA2024-T3 substrates was captured using linear polarisation resistance, electrochemical impedance spectroscopy, and potentiodynamic polarisation techniques at different exposure times to obtain the most comprehensive electrochemical picture of the corrosion inhibition over a 24-h period. The experimental results yield target parameters and additional input features that can be combined with computational descriptors to develop quantitative structure–property relationship (QSPR) models augmented by mechanistic input features.

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The preferential orientation of the perovskite (PVK) is typically accomplished by manipulation of the mixed cation/halide composition of the solution used for wet processing. However, for PVKs grown by thermal evaporation, this has been rarely addressed. It is unclear how variation in crystal orientation affects the optoelectronic properties of thermally evaporated films, including the charge carrier mobility, lifetime, and trap densities. In this study, we use different intermediate annealing temperatures Tinter between two sequential evaporation cycles to control the Cs0.15FA0.85PbI2.85Br0.15 orientation of the final PVK layer. XRD and 2D-XRD measurements reveal that when using no intermediate annealing primarily the (110) orientation is obtained, while when using Tinter = 100 °C a nearly isotropic orientation is found. Most interestingly for Tinter > 130 °C a highly oriented PVK (100) is formed. We found that although bulk electronic properties like photoconductivity are independent of the preferential orientation, surface related properties differ substantially. The highly oriented PVK (100) exhibits improved photoluminescence in terms of yield and lifetime. In addition, high spatial resolution mappings of the contact potential difference (CPD) as measured by KPFM for the highly oriented PVK show a more homogeneous surface potential distribution than those of the nonoriented PVK. These observations suggest that a highly oriented growth of thermally evaporated PVK is preferred to improve the charge extraction at the device level.@en

Zinc aluminium (Zn-Al) and lithium aluminium (Li-Al) – layered double hydroxides (LDH) coatings with incorporated inhibitors (Li−, Mo− and W−based) were successfully synthesized on AZ31 Mg alloy. Zn−Al LDH W and Li−Al LDH Li showed the highest corrosion resistance and were selected for further evaluation. SEM cross−section examination revealed a bi−layer structure composed of an outer part with loose flakes and a denser inner layer. XRD, FTIR, and XPS analysis confirmed the incorporation of the inhibitors. Post−treatments with corrosion inhibitors containing solutions resulted in the selective dissolution of the most external layer of the LDH coating, reducing the surface roughness, hydrophilicity and paint adhesion of the layers. Active corrosion properties were confirmed by SVET evaluation for the Zn−Al LDH W coating. The proposed active corrosion mechanism involves the ion−exchange of aggressive Cl⁻ ions, deposition of hydroxides and competitive adsorption of W−rich corrosion inhibitors.

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Refractory transition-metal (TM) diborides have high melting points, excellent hardness, and good chemical stability. However, these properties are not sufficient for applications involving extreme environments that require high mechanical strength as well as oxidation and corrosion resistance. Here, we study the effect of Cr addition on the properties of ZrB₂-rich Zr_1-xCr_xB_y thin films grown by hybrid high-power impulse and dc magnetron co-sputtering (Cr-HiPIMS/ZrB₂-DCMS) with a 100-V Cr-metal-ion synchronized bias. Cr metal fraction, x = Cr/(Zr + Cr), is increased from 0.23 to 0.44 by decreasing the power P_ZrB2 applied to the DCMS ZrB₂ target from 4000 to 2000 W, while the average power, pulse width, and frequency applied to the HiPIMS Cr target are maintained constant. In addition, y decreases from 2.18 to 1.11 as a function of P_ZrB2, as a result of supplying Cr to the growing film and preferential B resputtering caused by the pulsed Cr-ion flux. ZrB_2.18, Zr_0·77Cr_0·23B_1.52, Zr_0·71Cr_0·29B_1.42, and Zr_0·68Cr_0·32B_1.38 films have hexagonal AlB₂ crystal structure with a columnar nanostructure, while Zr_0·64Cr_0·36B_1.30 and Zr_0·56Cr_0·44B_1.11 are amorphous. All films show hardness above 30 GPa. Zr_0.56Cr_0.44B_1.11 alloys exhibit much better toughness, wear, oxidation, and corrosion resistance than ZrB_2.18. This combination of properties makes Zr_0·56Cr_0·44B_1.11 ideal candidates for numerous strategic applications.

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The present study shows results of friction stir welded (FSW) samples after different plastic deformation routes. The welds were made of coarse-grained and ultrafine-grained commercially pure aluminium. As a plastic deformation method a new hybrid process has been chosen, which resulted in obtaining samples with different characteristics of microstructure, which also differed in dependance of the examined plane. Microstructure observations showed that, regardless of the base material, due to continuous dynamic recrystallization a stir zone was characterized by equiaxial grains with an average size of 3.5–5.0 μm. However, significant differences in the changes of the microstructure in thermomechanically affected and heat affected zones have been obtained between welds. Microhardness profiles revealed a decrease in the stir zones in comparison with the initially deformed samples, but an increase for the annealed samples. Tensile tests showed differences between the samples. In the deformed samples, the rupture occurred in a stir zone, while in the undeformed samples in the base material. In addition, due to the application of 3D digital image correlation, it was possible to observe deformation and local changes between the weld zones during the tensile test. Additionally, local electrochemical measurements were performed with two sizes of working electrode, which included the application of microcapillary technique. The results showed higher corrosion resistance in 3.5% NaCl in the stir zones.

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The effect of sodium molybdate in inhibiting galvanic corrosion of Zn coating and mild steel is addressed. The inhibitor's performance was appraised by Zero Resistance Ammeter on HDG/mild steel galvanic coupling model in 0.05 M NaCl (+5 mM Na₂MoO₄) media. The effectiveness of Na₂MoO₄ was evaluated on HDG substrate mechanically scratched to reach the steel. Scanning Vibrating Electrode Technique was employed for assessing the distribution of j from scribed HDG surfaces. This local electrochemistry approach was repeated in NaCl solution to examine the behaviour of HDG when the Zn-coating is partially removed. Surface analysis supported all electrochemical results.

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