Tribological properties of tin and bronze coatings electrodeposited from acid baths

Electrodeposited copper, tin and bronze are widely used as protective and decorative coatings due to their good corrosion resistance and appearance. However, there are some applications in which these properties are not enough and a low coefficient of friction is required. It is known that tin has a good lubricity and that this property depends on the morphology of the deposit. Furthermore some authors have reported the use of electroplated bronze as a lubricating coating in the oil industry. The bath commonly used for the electrodeposition of this alloy is a cyanide-based electrolyte which produces high quality deposits but has several environmental problems during use and disposal owing to its high toxicity. Many cyanide free baths have been developed, either acid or alkaline, but too little information about the performance of the resulting deposits have been reported. The aim of this work is to develop an acidic noncyanide electrolyte for the electrodeposition of high quality bronze coatings and evaluate their tribological behavior.Centro de Investigación y Desarrollo en Tecnología de Pintura

Desarrollo de electrolito de cobreado en medio alcalino libre de cianuro

Desde ya hace muchos años en la industria de la galvanoplastia se utilizan los electrolitos basados en cianuro para obtener recubrimientos de cobre. Estos electrolitos son altamente tóxicos y se están haciendo numerosas investigaciones con el fin de obtener alternativas para su reemplazo. El objetivo del presente trabajo es estudiar el sistema de Cu+2-glutamato como reemplazo del cianuro y evaluar su idoneidad para la obtención de recubrimientos de cobre alcalino moderado (pH8) sobre sustratos de acero y de Zamak con fines industriales y decorativos. Para ello se realizaron experiencias de cobreado en las distintas geometría de celdas utilizadas en la industria a escala de laboratorio (celdas de cátodo plano con agitador magnético, celdas de cátodo oscilante y celdas de barril rotativo. Los depósitos obtenidos fueron caracterizados por diferentes técnicas. Se obtuvieron recubrimientos de cobre homogéneos, de aspecto brillante y de adecuada adherencia sobre los diferentes sustratos y en las distintas geometrías de celdas utilizadas

Tribological properties of tin and bronze coatings electrodeposited from acid baths

Electrodeposited copper, tin and bronze are widely used as protective and decorative coatings due to their good corrosion resistance and appearance. However, there are some applications in which these properties are not enough and a low coefficient of friction is required. It is known that tin has a good lubricity and that this property depends on the morphology of the deposit. Furthermore some authors have reported the use of electroplated bronze as a lubricating coating in the oil industry. The bath commonly used for the electrodeposition of this alloy is a cyanide-based electrolyte which produces high quality deposits but has several environmental problems during use and disposal owing to its high toxicity. Many cyanide free baths have been developed, either acid or alkaline, but too little information about the performance of the resulting deposits have been reported. The aim of this work is to develop an acidic noncyanide electrolyte for the electrodeposition of high quality bronze coatings and evaluate their tribological behavior.Centro de Investigación y Desarrollo en Tecnología de Pintura

Bronze electrodeposition from an acidic non-cyanide high efficiency electrolyte: tribological behavior

Bronze coatings were electrodeposited onto a rotating cylinder electrode from a novel non-cyanide acid plating bath with high efficiency (92%). Deposits were obtained from a phenol sulfonic acid bath and their morphology, phase composition and tribological behavior were characterized. Cyclic and linear sweep voltammetries were used to study the effect of organic additives on the reduction processes to achieve an adequate formulation. The resulting bronze deposit consisted of a mono α-phase matrix with a 78% Cu and 22% Sn composition. Dry sliding wear tests were carried out employing a homemade ball on ring system and the coefficient of friction and wear resistance were quantified at different normal loads. Surface characterization of the bronze coatings showed that the resulting roughness is detrimental for the wear resistance of the deposit. This is evidenced by a higher friction coefficient and wear volume of Cu/Sn compared to a conventionally electrodeposited copper coating.Centro de Investigación y Desarrollo en Tecnología de Pintura

Corrosion of conductor rolls in the electrogalvanizing line at Terniun

Conductor rolls in the electrogalvanizing line are made of Duplex Stainless Steel (DSS) and after some time in service they suffer surface deterioration leading to surface defects and rejections in high quality products. Repassivation kinetics and susceptibility to pitting corrosion for the austenitic and ferritic phases were studied. An electrochemical treatment that reproduces the actual industrial corrosive situation was applied to test different alloys in the laboratory. The Hastelloy C22 showed the best performance and was evaluated in the line during a complete production batch. The new roll presented a slight deterioration, much lower than the DSS rolls

Hybrid Materials : A Metareview

The field of hybrid materials has grown so wildly in the last 30 years that writing a comprehensive review has turned into an impossible mission. Yet, the need for a general view of the field remains, and it would be certainly useful to draw a scientific and technological map connecting the dots of the very different subfields of hybrid materials, a map which could relate the essential common characteristics of these fascinating materials while providing an overview of the very different combinations, synthetic approaches, and final applications formulated in this field, which has become a whole world. That is why we decided to write this metareview, that is, a review of reviews that could provide an eagle's eye view of a complex and varied landscape of materials which nevertheless share a common driving force: the power of hybridization

Nanostructured Thick Electrode Strategies toward Enhanced Electrode–Electrolyte Interfaces

This article addresses the issue of bulk electrode design and the factors limiting the performance of thick electrodes. Indeed, one of the challenges for achieving improved performance in electrochemical energy storage devices (batteries or supercapacitors) is the maximization of the ratio between active and non-active components while maintaining ionic and electronic conductivity of the assembly. In this study, we developed and compared supercapacitor thick electrodes using commercially available carbons and utilising conventional, easily scalable methods such as spray coating and freeze-casting. We also compared different binders and conductive carbons to develop thick electrodes and analysed factors that determine the performance of such thick electrodes, such as porosity and tortuosity. The spray-coated electrodes showed high areal capacitances of 1428 mF cm−2 at 0.3 mm thickness and 2459 F cm−2 at 0.6 mm thickness