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The corrosion control of WC-Co type hardmetals is steadily gaining momentum for novel crucial applications in the Oil & Gas and food industries. The corrosion rate of the Co-based binder, and the extent to which coupling to WC speeds it up, are strongly influenced by alloying. In this paper, we investigate the impact of Cr on the corrosion-product film formation of Co- and Co Ni based hardmetal binders in acidic, neutral and alkaline aqueous solutions. We centred our study on the role of Cr in driving the distribution of oxidized Co and Ni at the micrometre scale, thanks to synchrotron-based soft-X ray microspectroscopy. We have investigated morphochemical distributions for the following grades: Co 96 Cr 4 , Co 48 Ni 48 Cr 4 , Co 50 Cr 50. Chemical-state mapping has been complemented by electrochemical measurements and metallographic observations. Amounts of Cr and Ni of ca. 50% notably increase the corrosion resistance in all ambients, with a stronger beneficial effect of the former element. 4% addition of Cr results in slight positive effects, with the exception of the Co Ni system in alkaline ambient, that, together with Co 50 Cr 50 , outperforms the other grades. In all investigated alloy-ambient combinations, a continuous oxidized metal film grows, onto which micrometric island form of shape and dimensions that depend on the specific grade and aggressive conditions. Quantitative descriptors of chemical-state maps and their theoretical interpretation in terms of electrochemical phase-formation by oxy-hydroxide precipitation, allow to correlate the island patterns with the degree of pseudopassivation. Unlabelled Image • Role of Cr in corrosion resistance of Co- and Co-Ni-based hardmetal model binders. • Corrosion of Co Cr based grades studied in aerated aqueous solutions in pH range 1–10. • Soft-X ray microspectroscopy yields chemical-state maps of pseudopassivation films. • Pseudopassivation layers form oxidized metal patterns, depending on attack conditions. • Corrosion resistance correlates with morphochemical details of oxide film patterns. [ABSTRACT FROM AUTHOR]

• Highly durable and performing bifunctional alkaline Zn-air battery air electrodes. • Bifunctional GDEs, based on α-MnO 2 nanorods for ORR and Ni/NiO nanoparticles for OER. • Structural and spectral-imaging characterization of GDEs: pristine and post mortem. • Degradation mechanisms understood with STXM-based chemical-state mapping and TEM. • Molecular-level study of role of Zn2+ in electrolyte in electrocatalyst degradation. Electrically rechargeable alkaline zinc air batteries (RZAB) – currently still at the R&D stage –, have great potential for stationary, as well as prospectively mobile, electrochemical energy storage applications. Their chief appeal is that they are made of abundant, environmentally friendly, intrinsically safe, and cheap materials, with established recycling concepts and auspicious life-cycle costs. One of the key weak points of present-generation RZAB programs is the air gas-diffusion electrode (GDE). In fact, on the one hand, GDE fabrication and testing are generally based on poorly understood protocols, and, on the other hand, performance is challenged by efficiency and durability issues. This work is centred on the fabrication of a novel bifunctional GDE for the air side of RZABs, on the assessment of its electrochemical performance and on the identification of factors impacting its efficiency and durability. The electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are α-MnO 2 nanowires and Ni/NiO nanoparticles, respectively. The composition of the active layer was optimized with rotating ring-disc electrode (RRDE) electrocatalysts tests. The GDEs were fabricated by spray-coating an ink, formulated with the electrocatalysts and the PTFE binder in an aqueous matrix. Fabrication and functional performance of GDEs – in pristine form and after ageing under realistic RZAB conditions – are rationalized on the basis of Scanning Electron Microscopy (SEM), Scanning Transmission X-ray SpectroMicroscopy (STXSM) at the Mn l -edge and Transmission Electron Microscopy (TEM) analyses. Imaging and spectral imaging disclosed the morphological and chemical-state evolution, brought about by electrochemical cycling. Special attention was devoted to the understanding of the role played by the presence of zincate in the electrolyte on the performance and ageing of the reversible air electrodes. [Display omitted] [ABSTRACT FROM AUTHOR]

Human exposure to asbestos can cause a wide variety of lung diseases that are still a current major health concern, even if asbestos has been banned in many countries. It has been shown in many studies that asbestos fibers, ingested by alveolar macrophages, disrupt lung iron homeostasis by sequestering iron. Calcium can also be deposited on the fibers. The pathways along which iron and above all calcium interact with fibers are still unknown. Our aim was that of investigating if the iron accumulation induced by the inhaled asbestos fibers also involves calcium ions accumulation. Lung sections of asbestos-exposed mice were analyzed using an extremely sensitive procedure available at the synchrotron facilities, that provides morphological and chemical information based on X-ray fluorescence microspectroscopy (μ-XRF). In this study we show that (1) where conventional histochemical procedures revealed only weak deposits of iron and calcium, μ-XRF analysis is able to detect significant deposits of both iron and calcium on the inhaled asbestos fibers; (2) the extent of the deposition of these ions is proportionally directly related and (3) iron and calcium deposition on inhaled asbestos fibers is concomitant with the appearance of inflammatory and hyperplastic reactions. [ABSTRACT FROM AUTHOR]