Corrosion Behavior of Electrodeposited Nickel Coating Reinforced by Cr2O3 Particles

The objective of this work is the characterisation of the composite deposits Ni-Cr2O3 on copper substrate; these deposits are obtained from bath of electro-deposition of Nickel watts. The different electrodeposited layers are characterized by various analytical techniques such as adhesion quality, corrosion tests, Vickers microhardness, morphology by scanning electron microscopy Followed by EDX microanalysis and X-ray diffraction. The corrosion tests are realized in a solution of 3.5 % NaCl using lost mass method, polarization and impedance spectroscopy techniques. It was found that the composite coatings Ni-Cr2O3 have an homogeneous and compact morphology, well crystallized and exhibit a high degree of codeposition of Cr2O3 particles incorporated in the nickel matrix. The co-deposited films have very good hardness, adhere perfectly to the substrate and are more resistant to corrosion.

Study of Polyaniline/Poly(Sodium 4-Styrenesulfonate) Composite Deposits Using an Electrochemical Quartz Crystal Microbalance for the Modification of a Commercial Anion Exchange Membrane

One of the intended applications for the modification of ion exchange membranes with polyaniline (PAni) is to use it as a matrix to include chemical species that confer a special property such as resistance to fouling or ion selectivity. In particular, the inclusion of polyelectrolyte molecules into the PAni matrix appears to be the way to modulate these properties of selective membranes. Therefore, it must be clearly understood how the polyelectrolyte is incorporated into the matrix of polyaniline. Among the results obtained in this paper using poly(sodium 4-styrenesulfonate) (PSS) and an electrochemical quartz crystal microbalance, the amount of polyelectrolyte incorporated into PAni is found to be proportional to the PSS concentration in solution if its value is between 0 and 20 mM, while it reaches a maximum value when the PSS in solution is greater than 20 mM. When the anion exchange membranes are modified with these composite deposits, the transport number of chloride was found to decrease progressively (when the PSS concentration in solution is between 0 and 20 mM) to reach a practically constant value when a concentration of PSS greater than 20 mM was used.

The evolution of submarine slope-channel systems: Timing of incision, bypass, and aggradation in Late Cretaceous Nanaimo Group channel-system strata, British Columbia, Canada

Submarine channel systems convey terrestrially derived detritus from shallow-marine environments to some of the largest sediment accumulations on Earth, submarine fans. The stratigraphic record of submarine slope channels includes heterogeneous, composite deposits that provide evidence for erosion, sediment bypass, and deposition. However, the timing and duration of these processes is poorly constrained over geologic time scales. We integrate geochronology with detailed stratigraphic characterization to temporally constrain the stratigraphic evolution recorded by horizontally to vertically aligned channel-fill stacking patterns in a Nanaimo Group channel system exposed on Hornby and Denman Islands, British Columbia, Canada. Twelve detrital zircon samples (n = 300/sample) were used to calculate maximum depositional ages, which identified a new age range for the succession from ca. 79 to 63 Ma. We document five phases of submarine-channel evolution over 16.0 ± 1.7 m.y. including: an initial phase dominated by incision, sediment bypass, and limited deposition (phase 1); followed by increasingly shorter and more rapid phases of deposition on the slope by laterally migrating (phase 2) and aggrading channels (phase 3); a long period of deep incision (phase 4); and a final rapid phase of vertical channel aggradation (phase 5). Our results suggest that ∼60% of the evolutionary history of the submarine channel system is captured in an incomplete, poorly preserved record of incision and sediment bypass, which makes up <20% of outcropping stratigraphy. Our findings are applicable to interpreting submarine channel-system evolution in ancient and modern settings worldwide and fundamentally important to understanding long-term sediment dispersal in the deep sea.

Development of novel corrosion resistant electroless NI-P composite coatings for pipeline steel

In this research, coatings with various particles contents will be co-deposited within Ni–P deposits on AISI 1012 steel samples by electroless coating process. As a result, structural changes were evaluated, surface and cross-section morphology of composite deposits have been investigated by scanning electron microscopy (SEM), volumetric percentage of co-deposited particles have been determined using EDS analysis system, corrosion resistance of various EN coatings and current density were studied through potentiodynamic polarization, and mechanical properties were evaluated using wear and nano-indentation tests. The results showed that Alumina can give the best compromise between surface smoothness and deposition rate, Titanium can reach the highest levels of volumetric incorporation whereas Carbon can improve further lubrication effect on wear action, finally hardness and corrosion behavior had the best results with the existence of Alumina.

I depositi votivi di kotylai e kotyliskoi corinzi provenienti dal santuario demetriaco di Bitalemi a Gela

This paper concerns the study of the votive deposits, containing Corinthian kotylai and kotyliskoi, discovered in the Thesmophorion, situated on the Bitalemi hill at Gela (Sicily). The work, part of a broader analysis of these specific Corinthian classes, examines in depth the votive depositions made during the first phase of the sanctuary’s frequentation (5th layer). This report highlights six composite deposits that testify, through their material associations, some ritual features related to the Demeter Thesmophoros’ cult.

Effect of diamond particles on the microstructure and composition of pulse plated multilayer Ni-W/diamond composite coatings

The research encompasses the fabrication of multilayer Ni-Wdiamond composite deposits by pulse current electrodeposition. The mean surface diameter of the diamond used for the research was 0.9 microns. The composites were fabricated under various conditions and characterized by means of SEM, EDS and XRD to investigate and analyze their microstructure, grain size and elemental distribution along with variations in morphology under different conditions. The effect of variations in forward and reverse current density along with duty cycle and the combination of various aforesaid conditions on the coatings were studied and analyzed.

Composite Deposits Developed by Welding on Horizontal Mill Hammers

The paper presents the concept of designing active hammer edges of horizontal mills for grinding tungsten carbide waste by making composite layers deposited by welding. The new generation of hammers is carried out on the principles of preventive and repetitive maintenance, by endowment with wear addition, predetermined as volume and geometric configuration, depending on the specific conditions of uninterrupted use for a period of time established for economic reasons. The main demands that affect the integrity of the active areas of grinding mills (high pressure abrasion wear, thermo-mechanical fatigue) generate both material losses and output from working rates, as well as excessive elongation of the support elements under the combined action of centripetal force and of the pressure exerted by the ground load. Under these conditions, the technically and economically optimized solution is to design the modular active elements in the form of easily assembled detachable components, made of a low alloy steel with average tear resistance (450-600MPa) on which we deposit by welding layers of composite austenitic steel, hardened by compression, so as to increase the lifetime of the hammers by up to 35% compared to the present solution, which can be upgraded up to 3 times for reuse.