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More and more often cemented carbides employed for the production of wear resistant components have to face highly demanding service conditions, that combine different damage mechanisms. A key example is the range of tetraphasic (sea water, sand, liquid and gaseous hydrocarbons) flows encountered in the Oil&Gas extraction industry. In this study, such an tribochemical condition is simulated in a modified ASTM B611 abrasion testing apparatus, equipped with a three-electrode electrochemical system for in situ electrochemical measurements, enabling the replication of abrasion and corrosion synergistic effects. The effect of the metallic binder content and composition on the behavior of cemented tungsten carbide systems was investigated. The results highlight the role of alloyed binders, where the addition of heavy transition metals (Ru, Hf) is considered. The relationship between the tribological behavior and the mechanical properties of the tested grades is also reported, to support the selection of the grades for each application.

The anodic efficiency of zinc-air batteries with alkaline electrolytes is crucially affected by the formation of passivating films. The nature of these films is still poorly understood and notably influenced by the operating parameters and by the electrochemical polarization history. In particular, the anodic behaviour is strongly hysteretic and exhibits a sharp transition from the active dissolution branch to the pseudo-passive state. The space-time distribution of anodic areas in either state impacts the battery dynamics, with specially notable effects on electrically rechargeable devices. The present study on the one hand presents original fundamental results and their physico-chemical modelling, and on the other hand opens up the perspective of optical transduction of anode activity state in view of battery control, aimed at stabilizing the active dissolution state.

La produzione di energia elettrica da fonti rinnovabili potrebbe sostituire quella da combustibili fossili, ma il supporto di sistemi termici è attualmente inevitabile per la mancanza di dispositivi affidabili della taglia richiesta da applicazioni civili, trasportistiche ed industriali. La ricerca accademica e industriale è pertanto attivamente impegnata nell’identificazione di nuove strategie di accumulo, specialmente di tipo elettrochimico. Fra le tipologie di batteria in studio, i sistemi Zn-aria sono fra i più promettenti per ragioni di sicurezza, reperibilità delle materie prime, costo e sostenibilità. Questa memoria espone i recenti sviluppi nell’ambito delle celle a combustibile Zn-aria (ZAFC) basati sull’esperienza degli autori nella costruzione ed esercizio di un sistema di 1a generazione ZAFC-G1 (1). Dall’analisi delle criticità di ZAFC-G1 è stato possibile da una parte implementare migliorie cha hanno portato a un aumento della densità di potenza di un fattore 2,5, dall’altra si è riprogettato e realizzato tramite stampa 3D un sistema ottimizzato per alte densità di potenza e maggiore durabilità.

The production of electrical energy from renewable sources can in principle replace the current technologies based on fossil fuels. Nevertheless, source integration with thermal systems cannot be avoided at the moment, owing to the lack of safe, reliable and efficient large-scale storage devices. In particular, storage systems for the power scales required for practical civil, automotive and industrial applications are not available presently. Among the battery technologies being actively investigated, the Zn-air system is highly promising since the anodic material is safe, widely accessible, low-cost, easily recyclable and environmentally benign. This paper expounds recent developments in the field of Zn-air fuel cells (ZAFC). Based on the experience accumulated with a 1st-generation ZAFC (1) on the one hand, we have implemented a series of improvements that have allowed to increase the power density by a factor of 2.5 and on the other hand, we have completely re-designed a 2nd-generation device for high power density and better durability and built by additive manufacturing.

The production of electrical energy from renewable sources can in principle replace the current technologies based on fossil fuels. Nevertheless, source integration with thermal systems cannot be avoided at the moment, owing to the lack of safe, reliable and efficient large-scale storage devices. In particular, storage systems for the power scales required for practical civil, automotive and industrial applications are not available presently. Among the battery technologies being actively investigated, the Zn-air system is highly promising since the anodic material is safe, widely accessible, low-cost, easily recyclable and environmentally benign. This paper expounds recent developments in the field of Zn-air fuel cells (ZAFC). Based on the experience accumulated with a 1st-generation ZAFC (1) on the one hand, we have implemented a series of improvements that have allowed to increase the power density by a factor of 2.5 and on the other hand, we have completely re-designed a 2nd-generation device for high power density and better durability and built by additive manufacturing.