Coatings

This study investigates the tribological and electrochemical corrosion behavior of laser-clad nickel–aluminum bronze (NAB) coatings reinforced with WC particles (0, 8, 16 wt.%). Through microstructural characterization and phase analysis, it was found that in the NAB coating containing 16% WC, the WC particles and carbides were uniformly distributed, serving as a reinforcing scaffold. During the friction and wear process, they effectively reduced the contact area between the counter ball and the NAB matrix to a certain extent, smoothing the wear process and resulting in a more stable friction coefficient. Electrochemical testing demonstrates that WC addition significantly enhances corrosion resistance: NAB + 8%WC exhibits a low corrosion current density (i_corr), the highest polarization resistance, and the densest protective film. The dual mechanisms—grain boundary blocking and ion channel obstruction—reduce selective Al/Fe leaching and minimize Cl⁻ penetration. The 8% WC formulation optimizes the electrochemical performance, providing excellent corrosion resistance in a simulated marine environment.

Reducing the surface roughness of thermal barrier coatings (TBCs) improves engine aerodynamic efficiency and mitigates CMAS adhesion, but turbine blades’ complex geometries demand low-cost, damage-mzitigated finishing. This work employed drag finishing with spherical ceramic media, establishing a discrete element method (DEM) model to quantify abrasive trajectories, contact forces, and energy distributions, combined with surface characterization to study abrasive effects on columnar YSZ and modified GZO topcoats. Results show roughness reduction is constrained by fracture toughness and columnar unit local fracture, leading to different decay rates and late-stage improvement between YSZ and GZO. Introducing smaller abrasives enhances packing density via void filling, strengthens microscale cutting, and reduces strong normal impacts, promoting surface uniformization and suppressing localized damage. These findings guide mechanistic understanding of drag finishing on multi-material TBCs, as well as abrasive grading design and process parameter optimization.

Reducing the environmental impacts associated with road infrastructure is a key challenge in the transition toward more sustainable construction practices. Asphalt pavements, due to their extensive material use and energy demand over long service periods, offer significant opportunities for improvement through innovative materials and production technologies. This study evaluates the environmental performance of an asphalt pavement incorporating recycled tire crumb rubber and a warm mix asphalt additive (CR + WMA) in comparison with a conventional hot mix asphalt (HMA) pavement. A comprehensive cradle-to-grave life cycle assessment (LCA) was conducted in accordance with ISO 14040/44 standards, encompassing material production, construction, maintenance, and end-of-life stages. Different pavement service life scenarios were considered, and environmental impacts were quantified using sixteen midpoint categories of the environmental footprint (EF) 2.0 method. To enable a consistent comparison between pavement alternatives with different durability, results were normalized using a functional unit of 1 m²·year. The results show that the CR + WMA pavement consistently exhibits lower environmental impacts than the conventional HMA pavement across all impact categories. When identical service lives are assumed, impact reductions are primarily associated with lower production temperatures, partial substitution of virgin bitumen with recycled crumb rubber, reduced maintenance needs, and the normalization of life cycle impacts when results are expressed per m²·year. Overall, the CR + WMA pavement reduces life cycle environmental impacts by approximately 45%–60% across all EF midpoint categories compared to the conventional HMA pavement, depending on the impact category and service life scenario considered. These findings demonstrate the importance of explicitly accounting for service life and maintenance in pavement LCAs and highlight the potential of CR + WMA technology to reduce the life cycle environmental footprint of asphalt pavements, supporting more informed infrastructure design decisions and the development of more sustainable road pavement solutions.