Electrodeposited Zn-Ni-sisal Nanocrystals Composite Coatings - Morphology, Structure and Corrosion Resistance

Zn-Ni alloys have been used to decrease the corrosion rate of carbon steel substrates. These are used in applications such as bolt coatings, threaded parts, swift valves for gas pipelines, aircraft landing gear, brake system components and others. Zn-Ni coatings containing nanocrystals of cellulose (CNC) obtained from sisal fiber (Sif), a natural polymer, were manufactured using the electroplating technique. Obtaining the nanocrystals involved bleaching raw sisal fiber and then acid hydrolysis to extract the nanocrystal. The effect of the concentrations of the CNC-Sif (0% v/v, 2%v/v, 3%v/v, and 4%v/v) on the morphology and microstructure of the Zn-Ni coating was analyzed through Scanning Electron Microscopy (SEM), X-ray diffraction, and roughness measurements using confocal microscopy. The effect of the addition of CNC-Sif on the efficiency of galvanostatic deposition was analyzed. The corrosion rate through mass loss and electrochemical tests were also analyzed. The effect of adding CNC-SIF on coating microhardness investigated. This study show that the addition of nanocrystals alters the structure, the morphology, increases current efficiency and the corrosion resistance of the Zn-Ni coating and these effects are more significant with the addition of 2% v/v. The results obtained indicate that the addition of the CNC-Sif in the Zn-Ni coating is promising, because it reduces the energy consumed during the electrodeposition process in addition to increasing corrosion resistance of the Zn-Ni and the microhardness

Challenges in optimizing the resistance to corrosion and wear of amorphous Fe-Cr-Nb-B alloy containing crystalline phases

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Degradation of biodegradable implants: The influence of microstructure and composition of Mg-Zn-Ca alloys

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Corrosion properties of Fe–Cr–Nb–B amorphous alloys and coatings

International audienceIn the present work, we report on the corrosion properties of the Fe60Cr8Nb8B24 (at.%) alloy produced using pure and commercial materials in the following conditions: amorphous ribbons, partially crystallized ribbons and coatings produced by spray deposition and powder flame spraying process, in this case LVOF (low velocity oxygen fuel). The amorphous ribbons showed excellent corrosion resistance with formation of a stable passive film that ensured a very large passivation plateau. The (LVOF) coatings presented high fraction of amorphous phase with a layered structure, high porosity (16.2%) and low oxidation level (similar to 0.1%). The spray formed coatings presented crystalline structure with low porosity (1.9%) and low oxidation level (similar to 0.1%). The coatings showed higher corrosion current densities (up to two orders of magnitude) compared to the amorphous ribbons of the same composition for all pH. This deterioration in the corrosion properties were found to be impaired by the presence of crystalline phases

Influence of chromium concentration and partial crystallization on the corrosion resistance of FeCrNiB amorphous alloys

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Corrosion properties of amorphous, partially, and fully crystallized Fe68Cr8Mo4Nb4B16 alloy

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Corrosion resistance of pseudo-high entropy Fe-containing amorphous alloys in chloride-rich media

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