Study of the effect of electrolyte composition on adhesion and other properties of a coating-base system

Aluminum alloys with electroplated coatings and copper plated in particular gained multiple applications. However, pre-zincate treatment often fails to provide the desired adhesion of the coating. We present the results of studying the effect of the electrolyte composition on the adhesion and other properties of the coating-base system. It is shown that an electrolyte with a reduced content of sulfuric and phosphoric acids can be used for anodizing and the oxide films formed during anodizing are stable in the usual copper-plating sulfuric acid electrolyte which eliminates contact exchange and increases adhesion. The use of a modern scratch-test method provides numerical determination of the values of adhesion of copper coatings. The adhesion value depends on the surface porosity of the oxide film and on the type of anodized alloys. The results can be used to improve the technology of applying copper coatings, both as an independent coating and as an underlayer in multilayer coatings.

Purification of concentrated waste water of pcb production from copper ions

In modern conditions, it is important to create a comprehensive technology for processing wastewater containing copper compounds, with the disposal of precious metals, the organization of circulating water supply of the enterprise and obtaining safe for disposal sludge. Methods of sewage treatment of galvanic productions are considered. The results of experimental studies of the process of copper extraction from water by cementation on iron powder particles under static conditions are presented. The technological scheme of the reactor-cementator is given. The influence of various factors on the process of copper cementation – pH, concentration and ratio of iron and copper in the reaction mixture, contact time were studied. The time at which the greatest rate of change of residual copper concentration is observed is determined. The influence of the pH value of the cementation process was also determined. As a result of the obtained data, it is concluded that the concentration of hydrogen ions in the solution affects the course of the contact exchange reaction. The higher the acidity of the solution, the higher the recovery rate of copper. Promising directions for the creation of closed water circulation systems in the process of copper wastewater treatment are outlined.

Emplaced and embodied encounters: methodological reflections on transcultural research in contexts of Italian migration

This article explores the practical, ethical, and epistemological issues which arise when carrying out and sharing research in contexts of Italian migration, highlighting how greater reflexivity on our own geographic and historical location as researchers can productively inform and shape our understanding of sites of contact, exchange and confrontation in relation to contemporary Italy. Specifically, we write as researchers informed by ethnographic theories and practices, and who through our research have engaged in emplaced and embodied cultural encounters in sites which are identifiable as both transcultural and Italian. Drawing on vignettes from research in Italy and the UK, the article highlights some of the particular contradictions, opportunities and responsibilities generated by our respective positions. We address how our positionings as white, English and female scholars located within nationally-defined Italian Studies structures have raised pertinent questions of power, privilege and voice, as we place our own biographies and bodies, themselves shaped by specific colonial, national and local histories, into critical dialogue with those on and with whom we research. Through a discussion of these ‘irresolvable tensions’ of our research, we seek to practically engage with the broader imperative of finding new ways of studying and writing culture.

Обменные взаимодействия в гетероструктурах NiFe/Ta/IrMn в условиях дефицита Ta

In the NiFe/Ta/IrMn structures, the contributions of two types of exchange interactions are separated at the NiFe/IrMn interface, partially separated by non-magnetic Ta fragments. The first “contact” exchange corresponds to the NiFe/IrMn fragments. The second “interlayer” exchange is provided by the Ta conduction electrons in the NiFe/Ta/IrMn fragments. A comparison of the temperature dependences of the exchange bias in heterostructures with varied Ta spacer at fixed parameters of the ferromagnetic layers allowed us to separate the contributions of the above types of exchange interactions and to establish their temperature dependences. The energies of the exchange interactions in the NiFe/IrMn and NiFe/Ta/IrMn fragments were determined.