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The effect of high temperature exposure on the water wetting properties of co-electrodeposited superhydrophobic nickel-polytetrafluoroethylene (Ni-PTFE) nanocomposite coating on copper substrates was studied. This was accomplished by comparing the performance with a commercial superhydrophobic spray treatment (CSHST). The Ni-PTFE and CSHST coatings were both subjected to heating at temperatures up to 400 °C. Results showed that the Ni-PTFE was able to maintain its superhydrophobicity throughout the entire temperature range, whereas the CSHST became more wettable at 300 °C. Furthermore, additional abrasive wear tests were conducted on both materials that were subjected to heating at 400 °C. The Ni-PTFE remained highly non-wettable even after 60 m of abrasion length on 800 grit silicon carbide paper, whereas the CSHST coating was hydrophilic after 15 m. [ABSTRACT FROM AUTHOR]

Abstract Copper matrix composite materials with diamond particles are considered to be among the leading candidates as the heat sink materials for future electronic devices. However, today, these materials are mostly produced by high temperature-high pressure (HTHP) processes, which can be very costly. In order to explore an economically more viable approach of producing copper-diamond composite materials, we used electrodeposition to synthesize such materials and measured their thermal conductivities. The maximum thermal conductivity observed was 454 W/mK at 68.2 vol % diamond. In an attempt to improve the thermal conductivity further, titanium carbide (TiC) coatings were implemented on the diamond particles. The TiC coated diamond particles embedded in the electrodeposited copper matrix improved the thermal conductivity to 557 W/mK at 34.7 vol % , which is ∼ 40 % higher than 400 W/mK for pure copper. This value is comparable to currently available commercial HTHP heat sink materials. These results show that there is a potential of using electrodeposition an alternative synthesis method for producing copper-diamond composite materials for thermal managements. However, the formation of the microstructure at different electrodeposition current densities suggests that a careful process optimization is required to obtain a void-free Cu matrix between the embedded diamond particles. Highlights • Copper-diamond composite materials were produced using electrodeposition. • Thermal conductivity of copper was increased from 400 W/mK to 557 W/mK at 34.7 vol.% diamond. • Effects of diamond intermetallic coatings on the electrodeposition process are discussed. [ABSTRACT FROM AUTHOR]

Electrodeposited nanocrystalline and conventional polycrystalline NiFe alloys of similar iron content were investigated to understand the effect of grain size on the corrosion behaviour of these materials. Potentiodynamic polarization testing in 1 N H 2 SO 4 revealed similar active-passive-transpassive behaviour with negligible differences in the Tafel and transpassive regions regardless of grain size. It is shown that differences in the region of active dissolution are the result of strong contributions of sulfur impurities in the nanocrystalline electrodeposits rather than being due to grain size alone. [ABSTRACT FROM AUTHOR]

Previous research has shown that electrodeposited metal-diamond composite materials exhibit excellent mechanical properties, but their potential applications for thermal management in electronic devices have not been addressed. In contrast to common high temperature-high pressure (HTHP) methods, electrodeposition could offer a more economically viable route for making metal-diamond heat sink materials. In this study, nanocrystalline nickel-diamond composite materials were produced by electrodepositon. Using them as a prototype, the feasibility of using electrodeposited metal-diamond composite materials for heat sink applications was examined. The maximum thermal conductivity of nanocrystalline nickel-diamond composite was 200 W/mK at 61 vol% diamond, which is 2.6 times higher than 77 W/mK for pure nanocrystalline nickel. In addition, the thermal boundary conductance in the composite materials produced by electrodeposition was comparable to that previously reported for copper-diamond composite materials produced by the HTHP method. These results are a promising sign for producing electrodeposited metal-diamond composite materials with thermal conductivities high enough for heat management applications. [ABSTRACT FROM AUTHOR]

Copper coatings produced by additive manufacturing techniques often present complex microstructural heterogeneity. Reducing microstructural heterogeneity is critical for promoting uniform mechanical and corrosion behavior. The current study examines copper coatings at the closure weld zone of a prototype steel container designed to store used nuclear fuel. In this region, the copper coating is produced by two additive manufacturing processes: electrodeposition and cold spray. Microscopy analysis revealed a highly non-uniform microstructure in the as-processed state. After heat treatment at 350 °C for 1 h under inert conditions, this heterogeneity was significantly reduced resulting in favourable microstructural characteristics for the current application. Unlabelled Image • Corrosion barrier Cu coating for used nuclear fuel containers was analyzed. • Cu coating is made by electrodeposition and cold-spray at the closure weld zone. • Significant microstructural heterogeneity was observed in the as-deposited coating. • After an annealing treatment, the heterogeneity was greatly reduced. • The annealed microstructure is more favourable for the current application. [ABSTRACT FROM AUTHOR]