The mitigation of aluminum corrosion in HCl is crucial for economic, safety, and environmental considerations. The influence of Trimethoprim-Sulfamethoxazole (TMP-SMX) on the corrosion of aluminum in 1 M HCl was investigated through both electrochemical and computational methodologies. A notable difference in the open circuit potential values between the blank HCl and the inhibited system was recorded, indicating that TMP-SMX affects the electrochemical behavior of aluminum in 1 M HCl. The charge transfer resistance increased from 220 Ω cm2 without TMP-SMX to 610 Ω cm2 when 0.4 g/L of TMP-SMX was present, suggesting the establishment of a shielding TMP-SMX film on aluminium exterior. The current density exhibited a substantial decrease in the presence of TMP-SMX. The alteration in corrosion potential upon the incorporation of TMP-SMX remained below 85 mV, which suggests that TMP-SMX simultaneously retards anodic metal deterioration and cathodic hydrogen evolution. Computational simulation revealed that TMX and SMX maintain nearly parallel orientations with respect to the aluminum surface, suggesting enhanced surface coverage and interactions through heteroatoms and π-electron systems. ∆G⁰ values were negative, signifying that TMP/SMX spontaneously adhered to aluminum. Corrosion rate increased with rising temperature, but decreased with higher inhibitor concentrations. TMP-SMX has the potential to function as an environmentally friendly corrosion inhibitor for aluminium in HCl.

In the pursuit of low thermal conductivity is an enduring challenge that driving research in thermal barrier coating (TBC) materials. It has become a general consensus that thermal conductivity can be reduced by enhancing compositional complexity and introducing microstructural defects. However, these approaches inevitably increase the technological complexity to synthesize materials and degrades the oxygen barrier capability of the coatings. Therefore, synergistically optimizing the thermal conductivity and oxygen resistance of TBC materials remains a critical issue. Herein, a TBC candidate material SrTa₂O₆ with amorphous-like thermal conductivity and ultralow oxygen-ion conductivity is presented. The phase composition, microstructure, mechanical and thermal properties, and oxygen barrier capability of SrTa₂O₆ were investigated comprehensively. Notably, the Young's modulus, shear modulus and bulk modulus of SrTa₂O₆ is 207, 86, and 115 GPa respectively, which is similar to those of yttria-stabilized zirconia (YSZ). The Vickers hardness is comparable to YSZ at 8.9±0.1 GPa. The coefficient of thermal expansion (CTE) of SrTa₂O₆ is 10.8×10^-6 /K at 1200 ℃, which is close to that of YSZ. Attributed to the strong intrinsic phonon-phonon scattering arising from the oxygen vacancies introduced by nonstoichiometric ratios of Sr²⁺ and Ta⁵⁺, and the large difference in the interatomic bonding between Sr-O and TaO, SrTa2O6 exhibits amorphous-like thermal conductivity characteristics with the increment of temperature. The thermal conductivity of SrTa₂O₆ ranges from 1.69 to 2.12 W·m-1·K^-1 at 25-900 ℃, which is lower than most known thermal barrier materials, such as YSZ and rare earth tantalate. Moreover, SrTa2O6 exhibits ultra-low oxygen-ion conductivity of 2.07×10-5 S·cm^-1 at 900 ℃, which is three orders of magnitude lower than that of the state of art TBC material 8YSZ (3.47×10^-2 S·cm^-1). This work not only proves the application aspect of SrTa₂O₆ for TBC material, but also points out an avenue to balance the thermal conductivity and oxygen barrier ability of TBCs.

Improving the corrosion resistance of environmental barrier coatings (EBCs) to molten calcium-magnesium-aluminosilicate (CMAS) salt is an urgent requirement for aeroengine blades. In this work, a novel high-entropy (Ho_0.2Er_0.2Tm_0.2Yb_0.2Lu_0.2)₂Si₂O₇ ((5RE_0.2)₂Si₂O₇) environmental barrier coating material was developed, and molten CMAS corrosion resistance of (5RE_0.2)₂Si₂O₇) was systematically investigated at 1500 °C. The prepared (5RE_0.2)₂Si₂O₇ ceramic possesses a single and stable β-phase structure with high-temperature stability from room temperature to 1500 ℃. The thermal conductivity of (5RE_0.2)₂Si₂O₇ ranges from 1.46 to 3.49 W·m⁻¹·K^-1 at room temperature to 1500 ℃. A rapid reaction of (5RE_0.2)₂Si₂O₇ with molten CMAS produced Ca₂RE₈(SiO₄)₆O₂ apatite at 1500 ℃. The reaction layer thickness was only 95.9±8.6 μm which effectively inhibited the infiltration and diffusion of molten CMAS salt. In contrast, Yb₂Si₂O₇ ceramic, when exposed to molten CMAS at 1500 ℃, showed no reaction. Instead, the molten CMAS salt penetrated into the interior of Yb₂Si₂O₇ along grain boundaries and voids, forming bubble cracking and ultimately, structural degradation. These results suggest that the high-entropy (5RE_0.2)₂Si₂O₇ ceramic material is a potential candidate for next-generation EBC with excellent resistance to CMAS corrosion.