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J. Zoppas Ferreira

Bio: J. Zoppas Ferreira is an academic researcher from Universidade Federal do Rio Grande do Sul. The author has contributed to research in topics: Composite number & Corrosion. The author has an hindex of 4, co-authored 7 publications receiving 171 citations.

Papers
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TL;DR: In this article, NiP/SiC composite coatings were prepared by electrodeposition from a Brenner type plating bath containing SiC particles and cyclic voltammetry and immersion time were used to evaluate the electrochemical behaviour of these coatings.

58 citations

Journal ArticleDOI
TL;DR: In this paper, the NiP-SiC composite coatings were prepared by electrodeposition from a plating bath containing NiSO4·6H2O; NiCl2·6HO; NiO•6H 2O; H3PO3;H3PO4 ;N a2SO4 and SiC particles (average diameter of 600 nm).
Abstract: In this work, NiP-SiC composite coatings were prepared by electrodeposition from a plating bath containing NiSO4·6H2O; NiCl2·6H2O; H3PO3; H3PO4 ;N a2SO4 and SiC particles (average diameter of 600 nm) in suspension Anionic surfactant (SDS — sodium dodecyl sulfate, CH3 (CH2)11SO4Na) or cationic surfactant (CTAHS — cetyltrimethylammonium hidrogensulfate, C19H43NO4S) were also added to this suspension The number of incorporated particles by area unit (αnp/A) was evaluated by image analysis of micrographs obtained by scanning electron microscopy (SEM) It was observed that organic additive addition influences the incorporated SiC particles rate on the metallic matrix Addition of organic additives such as SDS or CTAHS modifies the characteristic of suspensions Depending on particle size organic additive addition can change the number of incorporated particles in deposits during growth of the matrix Decrease of the incorporated particle amount with the increase of particle size was verified The selective incorporation process is associated to the presence of organic additive and it was not dependent on surfactant charge

44 citations

Journal ArticleDOI
TL;DR: In this article, the effect of ligand type and the aging of the solution in the transport of trivalent chromium through Nafion 450 ion exchange membranes was studied.

38 citations

Journal ArticleDOI
TL;DR: In this article, a corrosion study of an AISI 316L austenitic stainless steel after different plasma ion nitriding conditions was carried out, and the properties of the coated stainless steel were measured by cyclic voltammetry and salt spray testing.
Abstract: This work is a corrosion study of an AISI 316L austenitic stainless steel after different plasma ion nitriding conditions. The properties of the coated AISI 316L were measured. The corrosion resistance was evaluated by cyclic voltammetry and salt spray testing. Sample surfaces were characterised by SEM and the phase determination with XRD analysis. Nanohardness was determined by using a Vickers indenter. The nitrided samples treated at 400°C, in a gaseous mixture of 5%N2 and 95%H2 for 4 and 5 h, had the best corrosion resistance. For the salt spray test, where the potential range is near the equilibrium potential, the nitrided material presented a reduced corrosion resistance. Through the control of the process parameters it is possible to improve the stainless steel surface hardness, combined with a good corrosion resistance. The highest value of temperature and N2 proportion increased the surface roughness and hardness, though it caused a decrease in corrosion resistance.

3 citations


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Journal ArticleDOI
01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations

Journal ArticleDOI
TL;DR: In this article, the incorporation rates of the dispersed particles have been achieved using high nanoparticle concentration in the electrolyte solution, smaller sized nanoparticles; a low concentration of electroactive species, ultrasonication during deposition and pulsed current techniques.
Abstract: Recent literature on the electrodeposition of metallic coatings containing nanosized particles is surveyed. The nanosized particles, suspended in the electrolyte by agitation and/or use of surfactants, can be codeposited with the metal. The inclusion of nanosized particles can give (i) an increased microhardness and corrosion resistance, (ii) modified growth to form a nanocrystalline metal deposit and (iii) a shift in the reduction potential of a metal ion. Many operating parameters influence the quantity of incorporated particles, including current density, bath agitation (or movement of work piece) and electrolyte composition. High incorporation rates of the dispersed particles have been achieved using (i) a high nanoparticle concentration in the electrolyte solution, (ii) smaller sized nanoparticles; (iii) a low concentration of electroactive species, (iv) ultrasonication during deposition and (v) pulsed current techniques. Compositional gradient coatings are possible having a controlled distribution of particles in the metal deposit and the theoretical models used to describe the phenomenon of particle codeposition within a metal deposit are critically considered.

734 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated and reviewed alternative salt recovery methods that have been developed and widely employed were reviewed, and economic analysis of concentrate utilization in comparison with disposal was performed.

212 citations

Journal ArticleDOI
TL;DR: In this paper, Ni and nickel matrix composite deposits containing nano-SiC particles were produced under both direct and pulse current conditions from an additive-free nickel Watts' type bath, and the study of the textural perfection of the deposits revealed that the presence of nano-particles led to the worsening of the observed [1/0/0] preferred orientation.

198 citations