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The present study investigated the surface morphology, phase composition, mechanical properties, and corrosion resistance of Ni-W alloy coatings prepared under current densities of 1–5 A/dm², after undergoing heat treatment at 400 °C, 600 °C, and 900 °C. The grain size of the as-plated Ni-W alloy coating was below 10 nm. After heat treatment at different temperatures, the grain size increased, reaching a maximum value of around 30 nm at 900 °C. Heat treatment crystallized and altered the structure of the coating. Different heat treatment temperatures yielded different precipitates, including Ni4W, Ni6W6C, and WC. The highest coating hardness (820–940 Hv) was achieved at 400 °C, while the best corrosion resistance was achieved at 600 °C. The precipitation hardening phase can be obtained by proper heat treatment temperature, yielding the desired properties of the composite coating. [ABSTRACT FROM AUTHOR]

Reduced graphene supported Co‐Sn‐Pd nanoparticle catalysts(Co0.2SnxPdy/rGO, x + y = 0.4) were successfully synthesized by reducing the trace amounts of ions (Pd2+, Sn2+, and Co2+) in the presence of reduced graphene via an ultrasonic irradiation method. Characterization of the Co0.2SnxPdy/rGO catalysts by X‐ray diffraction (XRD) and transmission electron microscopy (TEM) indicates that the Co0.2Sn0.2Pd0.2/rGO catalyst with a mean diameter of ~3.8 nm is close to a single‐phase solid solution. X‐ray photoelectron spectroscopy (XPS) shows the binding energy of metallic Pd shifts to a higher angle in the Co0.2SnxPdy/rGO (x + y = 0.4) catalysts, indicating a shift of Pd electronic centre upon alloying with Co and Sn. Conventionally, ternary Co‐Sn‐Pd/rGO catalysts show greater oxygen reduction reaction (ORR) activities and durability than binary Pd‐Co/rGO catalyst and 20 wt% Pt/C catalyst even at a very low Pd content. Among of the synthetic catalysts, the Co0.2Sn0.2Pd0.2/rGO catalyst exhibits the best ORR activity (E1/2 = 0.91 V, k = −57 mV · dec−1) and dominates a 4‐electron pathway in the ORR process (n = 3.95 ± 0.09, H2O2<4%). Also, the Co0.2SnxPdy/rGO (x + y = 0.4) catalysts display a remarkable advantage of high methanol tolerance compared to that of the commercial 20 wt% Pt/C catalyst, which make them potential candidates for direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

A Ni-W alloy containing about 13at.% of tungsten was deposited on carbon cloth (CC) by electrodeposition initially, and then carbon nanotubes (CNTs) were grown thereon by chemical vapor deposition (CVD), fabricating a selfsupported CNTs/Ni-W/CC composite electrode. The results of electrochemical test showed that the composite electrode exhibited good catalytic performance for hydrogen evolution reaction (HER) in 1 mol/L NaOH aqueous solution. The CNTs/Ni-W/CC composite electrode fabricated at 900 °C (the temperature of heat preservation in CVD) showed the best electrocatalytic activity among all the prepared samples. Its overpotential was 118.2 mV at a cathodic current density of 10 mA/cm2 and its Tafel slop was 97.4 mV/dec. The cathodic current density of this composite electrode could exceed that of commercial Pt/C material at a relatively high overpotential. This composite electrode also showed good long-term stability for HER. [ABSTRACT FROM AUTHOR]

Ni-W-Al2O3 nanocomposite coatings were deposited on the low-carbon steel substrates from aqueous sulfate-citrate electrolytes containing various amounts of Al3O2 nanoparticles. Their surface morphology, element and phase composition were carried out using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The corrosion resistance was carried out using the potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS). It is shown that incorporation of Al2O3 nano-particles into amorphous Ni-W coating would transform its structure to being crystalline and influence its properties. The hardness sharply increases and corrosion resistance performance significantly decreases even after few Al2O3 nanoparticles (2 g/L) were added into the bath. In addition, with increase of Al2O3 addition in the bath, a tendency of increase in hardness and corrosion resistance performance is observed. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, nano-SiO2 was used as an accelerator for improving the microstructure and the corrosion resistance of phosphate coating on carbon steel. The chemical composition and microstructure of the coatings were analyzed by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The effects of nano-SiO2 on weight, roughness and corrosion resistance of the phosphate coatings were also investigated. Results show that the compositions of phosphate coating were Zn3(PO4)2·4H2O (hopeite), and Zn2Fe(PO4)2·4H2O (phosphophylite). The phosphate coatings became denser due to the addition of nano-SiO2 which reduced the size of the crystal clusters. The average weight of phosphate coatings approximately linearly increased with the nano-SiO2 content in the bath from 0 to 4g/L, and the phosphate coatings formed in bath containing 2g/L nano-SiO2 showed the highest corrosion resistance in 5wt.% sodium chloride solution at ambient temperature. Nano-SiO2 would be widely utilized as a phosphating additive to replace the traditional nitrite, due to its less pollutant and its better quality of the coating. [Copyright &y& Elsevier]

Electrocatalytic water splitting is a desirable and sustainable strategy for hydrogen production yet still faces challenges due to the sluggish kinetics and rapid deactivation of catalysts in the oxygen evolution process. Herein, we utilized the metal-catalyzed growth technology and phosphating process to fabricate self-supported electrodes (Co x P y @CNT-CC) composed of carbon nanotube (CNT) arrays grown on carbon cloth (CC); thereinto, cobalt-based phosphide nanoparticles (Co x P y ) are uniformly encapsulated in the cavity of the CNTs. After further optimization, when the nanoparticles are in the composite phase (CoP 2 /Co 2 P), CoP 2 /Co 2 P@CNT-CC served as catalytic electrodes with the highest activity and stability for electrocatalytic water splitting in an alkaline medium (1.0 M KOH). The as-prepared CoP 2 /Co 2 P@CNT-CC integrates the advantages of the abundant active sites and confinement effect of CNTs, imparting promising electrocatalytic activities and stability in catalyzing both hydrogen evolution reaction and oxygen evolution reaction. Remarkably, electrocatalytic water splitting cells assembled using CoP 2 /Co 2 P@CNT-CC electrodes as the cathode and anode, respectively, require a cell voltage of 1.55 V at 10 mA cm -2 , which is lower than that of the commercially noble Pt/C/CC and RuO 2 /CC catalyst couple (1.68 V). Besides, a CoP 2 /Co 2 P@CNT-CC||CoP 2 /Co 2 P@CNT-CC system shows outstanding durability for a period of 100 h at 10 mA cm -2 . This work may provide new ideas for designing bifunctional electrocatalysts for applications in electrocatalytic water splitting.