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To prevent corrosion or abrasion damage of equipment used in hydrogen sulfide (H2S) and sand conditions, high wear and corrosion-resistant coatings are needed. In this study, a cemented carbide Cr3C2–25NiCr coating was applied to 304 stainless steel substrate via high-velocity oxygen fuel thermal spraying to investigate its wear and corrosion resistance in an oil and gas field model environment. The coating exhibits high hardness (1062.4HV0.1) that is five times greater than the substrate and a 50% reduction in wear pit depth. The corrosion rate of the coating is 72% less than that of stainless steel (0.17 mm/y). These results suggest that Cr3C2–25NiCr coating has great potential for use in the oil and gas industry. [ABSTRACT FROM AUTHOR]

AISI 304 austenitic stainless steel was low-temperature liquid nitrided in a molten salt bath at 703 K for 8 hours, which produced a 3-layered structure consisting of a top oxide layer, an intermediate nitrogen-rich layer and a bottom carbon-rich layer. The effect of nitriding on its corrosion resistance was investigated in a H2S environment. The corrosion rate of the untreated sample is about 3.3 times that of the nitrided sample after H2S corrosion. Corrosion pits can be clearly observed on the surface of the untreated sample, while the nitrided sample surface remained relatively intact. Both the oxide layer and the nitrogen-rich layer can help reduce the hydrogen permeation, which is beneficial for combating hydrogen embrittlement. The corrosion products mainly consisted of oxides, hydroxides, and sulfates. The nitrided layers can serve as a barrier to corrosion, thus preventing the corrosion of the substrate material. Active nitrogen in the nitrided layer reacts with H ions to form NH4+, which effectively prevents further acidification of the local area and inhibits the occurrence of pitting corrosion and the dissolution rate of the metal in the etching hole, thus improving the local corrosion resistance of the stainless steel. [ABSTRACT FROM AUTHOR]

Recently, perovskite photodetectors (PDs) are risen to prominence due to substantial research interest. Beyond merely tweaking the composition of materials, a cutting-edge advancement lies in leveraging the innate piezoelectric polarization properties of perovskites themselves. Here, the investigation shows utilizing Ti 3 C 2 T x , a typical MXene, as an intermediate layer for significantly boosting the piezoelectric property of MAPbI 3 thin films. This improvement is primarily attributed to the enhanced polarization of the methylammonium (MA + ) groups within MAPbI 3 , induced by the OH groups present in Ti 3 C 2 T x . A flexible PD based on the MAPbI 3 /MXene heterostructure is then fabricated. The new device is sensitive to a wide range of wavelengths, displays greatly enhanced performance owing to the piezo-phototronic coupling. Moreover, the device is endowed with a greatly reduced response time, down to millisecond level, through the pyro-phototronic effect. The characterization shows applying a -1.2% compressive strain on the PD leads to a remarkable 102% increase in the common photocurrent, and a 76% increase in the pyro-phototronic current. The present work reveals how the emerging piezo-phototronic and pyro-phototronic effects can be employed to design high-performance flexible perovskite PDs., (© 2024 Wiley‐VCH GmbH.)