Increasing demand for sustainable approaches to mining and raw material extraction, has prompted the need to explore advanced methods of surface modification for structural steels used in the extractive industry. The technology of powder plasma transferred arc welding (PPTAW), was used in this study as a surface modification technique to improve upon the abrasive wear resistance of structural steel grade EN S355. PPTAW process parameters, namely, plasma transferred arc (PTA) current and plasma gas flow rate (PGFR), were varied, and the effects of the variation were studied and used as criteria for selecting optimum conditions for further studies and parametric reproducibility. Two metal matrix composite (MMC) powders were used in the process, having compositions of Ni-Si-B+60wt%WC (PG) and Ni-Cr-Si-B+45wt%WC (PE). Microstructural observation under a scanning electron microscope (SEM) revealed a dendritic, multi-directional microstructure consisting of partially dissolved primary tungsten carbide particles and secondary tungsten carbide precipitates within the MMC solid solution. The hardness of the surface layers was higher than that of a reference AR400 steel by more than 263 HV. Final surface layers obtained from the MMC powders had abrasive wear resistance up to 5.7 times that of abrasion-resistant reference AR400 steel. Alloying the MMC matrix with chromium increased the hardness by 29.4%. Under the same process conditions, MMC powder with 60wt% WC reinforcement had better abrasive wear resistance by up to 45.8% more than the MMC powder with 45wt% WC.

Inorganic metal halide perovskites such as CsPbI3 are promising for high‐performance, reproducible and robust solar cells. However, inorganic perovskites are sensitive to humidity, which causes the transformation from the black phase to the yellow δ, non‐perovskite phase. Such phase instability has been a significant challenge to long‐term operational stability. Here, we report a surface dimensionality reduction strategy, using 2‐(4‐aminophenyl) ethylamine cation to construct a Dion‐Jacobson 2D phase that covers the surface of the 3D inorganic perovskite structure. The Dion‐Jacobson layer mainly grew at the grain boundaries of the perovskite, effectively passivating surface defects and providing favourable interfacial charge transfer. The resulting inorganic perovskite films exhibited excellent humidity resistance when submerged in an aqueous solution (Isopropanol: Water = 4: 1v/v) and exposed to a 50% humidity air atmosphere. The DJ 2D/3D inorganic perovskite solar cell (PSC) achieved a power conversion efficiency (PCE) of 19.5% with a Voc of 1.197 eV. It retained 83% of initial PCE after 1260 h of maximum power point tracking under 1.2 sun illumination. Our work demonstrates an effective way for stabilising efficient inorganic perovskite solar cells.This article is protected by copyright. All rights reserved

This study explores the use of powder plasma transferred arc welding (PPTAW) as a surface layer deposition technology to form hardfaced coatings to improve upon the wear resistance of mild steel. Hardfaced layers were prepared using the PPTAW process with two different wear-resistant powders: PG 6503 (NiSiB + 60% WC) and PE 8214 (NiCrSiB + 45% WC). By varying the PPTAW process parameters of plasma gas flow rate (PGFR) and plasma arc current, hardfaced layers were prepared. Microscopic examinations, penetration tests, hardness tests, and abrasive wear resistance tests were carried out on the prepared samples. Hardfacings prepared with PG 6503 had a hardness of 46.3–48.3 HRC, while those prepared with PE 8214 had a hardness of 52.7–58.3 HRC. The microhardness of the matrix material was in the range of 573.3–893.0 HV, while that of the carbides was in the range of 2128.7–2436.3 HV. The abrasive wear resistance of the mild steel was improved after deposition of hardfaced layers by up to 5.7 times that of abrasion-resistant heat-treated steel, Hardox 400, having a nominal hardness of approximately 400 HV. The hardness and wear resistance were increased upon addition of Cr as an alloying element. Increasing the PGFR increased the hardness and wear resistance of the hardfacings, as well as increasing the number of surface cracks. Increasing the plasma transferred arc (PTA) current resulted in hardfacings with fewer cracks but lowered the wear resistance.

With the aim of improving the excellent mechanical properties of the SLM-produced AlSi10Mg alloy, this research focuses on post-processing using ECAP (Equal Channel Angular Pressing). In our article, two different post-processing strategies were investigated: (1) low-temperature annealing (LTA) and subsequent ECAP processing at 150 °C; (2) no heat treatment and subsequent ECAP processing at 350 °C, 400 °C and 450 °C. The microstructure and mechanical properties of this alloy were analyzed at each stage of post-treatment. Metallographic observations, combined with SEM and EBSD studies, showed that the alloys produced by SLM have a unique cellular microstructure consisting of Si networks surrounding the Al-based matrix phase. Low-temperature annealing (LTA), followed by ECAP treatment, facilitated the microstructural evolution of the alloy with partial breakup of the Si network and observed nucleation of β-Si precipitates throughout the Al matrix. This resulted in a Vickers microhardness of 153 HV and a yield strength of 415 MPa. The main results show that post-processing of SLM-produced AlSi10Mg alloys using ECAP significantly affects the microstructural evolution and mechanical properties of the alloy.

Stability issues could refrain from commercializing lead halide perovskite solar cells (PSCs) despite having comparable power conversion efficiency (PCE) to silicon solar cells. Overcoming drawbacks affecting their long‐term stability is gaining incremental importance. Excess lead iodide (PbI2) causes perovskite degradation, although it aids in crystal growth and defect passivation. Herein, we synthesized functionalized oxo‐graphene nanosheets (Dec‐oxoG NSs) to effectively manage the excess PbI2. Dec‐oxoG NSs provide anchoring sites to bind the excess PbI2 and passivate perovskite grain boundaries, thereby reducing charge recombination loss and significantly boosting the extraction of free electrons. The inclusion of Dec‐oxoG NSs leads to a PCE of 23.7% in inverted (p‐i‐n) PSCs. Devices retain 93.8% of their initial efficiency after 1,000 hours of tracking at maximum power points under continuous one‐sun illumination, and exhibit high stability under thermal and ambient conditions.