Papers by Neide Aparecida Mariano Mariano
Materials Research, Nov 13, 2017
The thermal treatments employed in alloys are essential to obtaining desired microstructures and ... more The thermal treatments employed in alloys are essential to obtaining desired microstructures and corrosion resistance properties. In this paper the low carbon martensitic steel 13Cr4Ni0.2C with different tempering temperatures was studied using potentiodynamic polarization technique in synthetic marine environment, in order to evaluate the effect of the tempering temperature on the steel corrosion resistance in an environment that simulates the conditions of use in oil and gas production. Microscopy results showed differences in the microstructure of tempered steel at low (620°C) and high (770°C) temperatures, indicating the appearance and extending of martensite laths with increasing temperature. Polarization tests showed that tempering temperature located between 620°C and 710°C indicated passive film formation and tempering temperatures of around 620 °C showed better resistance values to pitting corrosion.
Cerâmica, 2013
Poços de Caldas é um importante centro hidrotermomineral do Brasil, o qual apresenta depósitos de... more Poços de Caldas é um importante centro hidrotermomineral do Brasil, o qual apresenta depósitos de argilas não plásticas para as quais não há registros significativos a respeito da caracterização direcionada destes materiais, o que prejudica estudos de aplicação industrial. Estas argilas não plásticas, não aproveitadas, vêm sendo armazenadas em galpões ou a céu aberto, o que gera um elevado custo para a indústria, além de transformar-se em um passivo ambiental. No presente trabalho realizou-se o estudo químico-mineralógico de seis amostras de argilas de baixa plasticidade, além da caracterização preliminar destas amostras quanto à granulometria, plasticidade e propriedades cerâmicas básicas, visando ampliar os horizontes das investigações destes materiais. Este estudo preliminar mostrou que, de maneira geral, as amostras são compostas por minerais refratários como caulinita e gibbsita, apresentando teores menos significativos de outras fases, como quartzo, vermiculita e illita. Junta...
Materialwissenschaft und Werkstofftechnik, 2005
ABSTRACT Many studies have been conducted to obtain toughness in ceramic-ceramic and metal-cerami... more ABSTRACT Many studies have been conducted to obtain toughness in ceramic-ceramic and metal-ceramic composites, using new processing techniques or by addition of metallic inclusions in the ceramic matrix. The oxidation behavior of metallic inclusions, niobium and nickel metallic particles embedded in an Al2O3-ZrO2 matrix, was measured through thermogravimetric analysis. In this work oxidation mechanisms were proposed and kinetic parameters defined using a software module for the kinetic analysis of thermal measurements by means of multiple linear or non-linear regression. The morphology of the oxidized surfaces of the samples was examined by using scanning electron microscopy. Oxides were identified by X-ray diffraction. The oxidation kinetics of metallic particles of niobium and nickel are highly complex, for they depend on various factors, i.e., metal’s characteristics, processing of the composite, oxygen diffusion through the matrix, grain boundaries, and heating rate applied to the material.Oxidationskinetik metallischer Einschlüsse in einem Verbundwerkstoff mit einer Al2O3-ZrO2 MatrixIn vielen Studien wurde versucht, Keramik-Keramik- oder Metall-Keramik-Verbunde zäher zu gestalten. Dazu wurden neue Verarbeitungstechniken benutzt oder metallische Einschlüsse in die keramische Matrix eingebaut. Das Oxidationsverhalten von Nickel- und Niobpartikel, die in eine Al2O3-ZrO2-Matrix eingebettet wurden, wird in dieser Arbeit durch thermogravimetrische Analyse untersucht. Die Messergebnisse werden mittels linearer und nicht-linearer Regressionsrechnung ausgewertet, so dass Oxidationsmechanismen vorgeschlagen und die kinetischen Parameter definiert werden können. Die Morphologie der oxidierten Probenoberflächen wurde rasterelektronenmikroskopisch untersucht. Die Oxide wurden durch Röntgendiffraktometrie identifiziert. Die Oxidationskinetik der metallischen Nb-und Ni- Partikel ist äußerst komplex, weil sie von vielen verschiedenen Faktoren abhängt, z. B. vom Metall selber, von der Art der Herstellung des Verbundwerkstoffs, von der Sauerstoffdiffusion durch die Matrix und die Korngrenzen und von der Aufheizgeschwindigkeit des Materials.
Materials Science and Engineering: A, 2003
Nanocrystalline FeCuNbSiB alloys obtained from the partial crystallization of amorphous alloys ha... more Nanocrystalline FeCuNbSiB alloys obtained from the partial crystallization of amorphous alloys have attracted technological attention due to their excellent magnetic properties, but the relationship between corrosion resistance and magnetic properties is not well established. The influence of Nb as an alloying element and effect of partial crystallization on the corrosion resistance of Fe73.5Si13.5B10Cu1, Fe73.5Si13.5B7Nb3Cu1 and Fe73.5Si13.5B5Nb5Cu1 amorphous alloys were studied
Matéria (Rio de Janeiro), 2009
A nitretação consiste de um tratamento de endurecimento superficial, sob a ação de um ambiente ni... more A nitretação consiste de um tratamento de endurecimento superficial, sob a ação de um ambiente nitrogenado, a temperatura e tempo determinados, podendo ser convencional (líquida e gasosa) ou por plasma. Neste trabalho foi utilizado o aço ferramenta AISI H10 modificado, nitretado a plasma com pós-oxidação e em banho de sal, visando à obtenção de uma camada com elevada dureza e resistente à corrosão. A microestrutura da camada nitretada foi caracterizada por microscopia eletrônica de varredura e por difração de raios-X. A profundidade efetiva da camada foi determinada pelo perfil de microdureza e a resistência à corrosão foi avaliada em solução aquosa de 0,5 mol L-1 de cloreto de sódio, por ensaios de polarização potenciodinâmicos, e por ensaios em câmara de névoa salina. A microestrutura obtida após o tratamento térmico prévio de têmpera e revenimento, foi uma matriz constituída de martensita revenida, com a presença de carbonetos esferoidizados, dispersos homogeneamente na matriz. A...
Materials Science Forum, 2014
The inclusion of alternative materials in the composition of asphaltic masses aims to solve the p... more The inclusion of alternative materials in the composition of asphaltic masses aims to solve the problems arising from the disposal, in the environment, of industrial waste discarded; however, to ensure that such inclusion doesn't damage the characteristics and properties of the asphaltic mass, it is necessary that the mixtures, composed by mineral aggregates, PAC and filler, are previously submitted to the standardized essay. It is known that the filler is mainly responsible for the absorption of the PAC and that, the greater the amount of the PAC utilized on the asphaltic mass, the bigger the costs. Thus the characteristics of the filler, as well the rate of packing of the constituents of the asphaltic mass affects directly the cost and properties of the final product. Given the previous subject, in this work it was aimed to study the effect of the addition of low plasticity clay and peat in the final properties of the asphaltic masses.
Research, Society and Development, 2021
Duplex stainless steels correspond to a class of steel in which the microstructure is composed ba... more Duplex stainless steels correspond to a class of steel in which the microstructure is composed basically by the phases ferrite and austenite. Given the metastable character of ferrite, associated phase transformations can occur during thermal treatments, which can lead to a reduction in corrosion resistance. Therefore, the aim of this work was to evaluate the influence of the solution-treated at 1100°C for 30min and aging at 500 and 600°C for 1, 3 and 12h, on the microstructure and corrosion resistance of DSS UNS S31803. The steels were characterized by SEM, EDS, XRD, hardness, microhardness and thermal analysis. The steels aged at 500°C for 1h presented the phase alpha line dispersed in the ferrite, and the steels aged at 600°C for 12h presented the phases alpha line, sigma and chi. In the assays of double cycle potentiodynamic reactivation in solution of 0.5M H2SO4 and 0.01M KSNC, it was observed that no sensitization occurred. Furthermore, in the tests of cyclic potentiodynamic p...
Materials Research, 2019
Titanium is used in orthopedic and orthodontic implants because it has good corrosion resistance ... more Titanium is used in orthopedic and orthodontic implants because it has good corrosion resistance and excellent biocompatibility. Thus, studies seek to obtain a coating to improve the adhesion between the bone and the implant, by modifying the metal's surface. The objective of this work was to biomimetically coat C.P. Ti with hydroxyapatite doped with silver nitrate, a component with antimicrobial properties, coating the metallic-ceramic composite with a polycaprolactone polymer film, which is known by generate improved implant-tissue interaction, and reducing postoperative complications from bacterial infections. The characterization of the material demonstrated the existence of the coating overall surface of the metallic substrate. The results obtained from the bacterial culture tests with Staphylococcus aureus showed that nitrate was effective in reducing the amount of live bacteria present in the supernatant, as well as those adhered to the surface of the material. In addition, the polymeric coating did not prevent the release of the bactericidal agent, not interfering in the effect there.
Materials Research Express, 2020
Pure titanium and its alloys have been widely applied as implant material with excellent results ... more Pure titanium and its alloys have been widely applied as implant material with excellent results in a long term because of their excellent biocompatibility and resistance to corrosion. Biomaterials with porous structure optimize the interfacial resistance between the material and the bone, leading to a more efficient fixation of the implant by bone growth in the pores. Titanium implants covered with calcium phosphates have received increasing application in odontology and orthopedics, and clinical studies indicate that the healthy bone tissue responds positively to the bioceramic surfaces. Calcium phosphates, particularly hydroxyapatite in the form of coating, provide a bioactive surface to the metal, which induces the direct union between the implant and the bone tissue. Consequently, the time for osseointegration and, therefore, the total time for treatment, can be reduced. Researches have been conducted to obtain a coating, in order to enhance the adherence between bone and implant, modifying the metal surface, allowing an efficient regeneration of the bone tissue, osseointegration and accelerating its growth. In this work, the effect of coating by the biomimetic method on a titanium substrate was studied, consisting of the immersion of the substrate in a synthetic SBF (Simulated Body Fluid) solution, with composition, pH and temperature similar to blood plasma. The coating was efficient for obtaining hydroxyapatite, which was confirmed by the techniques of scanning electron microscopy (SEM), X-ray diffraction (XRD) and infrared. The bioactivity assay revealed that the samples which received the coating with 1.5 SBF presented bioactive characteristic by the formation and development of the carbonated hydroxyapatite on the surface, in a superior way to the samples without coating, thus suggesting a fast osseointegration of the bone with the implant. The polarization curves showed that the titanium without coating presented a higher resistance to corrosion compared to the titanium with coating.
Materials Today Communications, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Materials Science Forum, 2018
Commercially pure titanium and its alloys have been widely applied as implant materials with exce... more Commercially pure titanium and its alloys have been widely applied as implant materials with excellent long-term results and present benefits compared to other metal biomaterials because of the good mechanical strength and modulus of elasticity with values close to those of the bone. Titanium implants coated with hydroxyapatite give the metal a bioactive surface, which induces a direct connection between the implant and the bone tissue. As a consequence, the time for osseointegration, and hence the total treatment time, may be reduced. This paper aimed at studying the bactericidal effect of silver nitrate at 10 ppm and 100 ppm, incorporated in the layer on the surface of commercial titanium. The results showed efficiency in both osseointegration and bactericidal effect, confirmed by scanning electron microscopy, X-ray diffraction and corrosion tests. The bacterial culture tests, by means of the halo inhibition tests, indicate that the doping with AgNO3in concentrations 10 and 100 pp...
Materials Science Forum, 2018
The formation of intermetallic phases during thermal treatments is a decisive point for the perfo... more The formation of intermetallic phases during thermal treatments is a decisive point for the performance of duplex stainless steels, which may prevent the obtaining or provoke degradation of their properties. This paper presents an investigation on the corrosion resistance of duplex SAF 2205 steel as received and after solution annealing treatment. The objective was to evaluate the correlation between the solution annealing time, the resulting microstructural changes and the corrosion resistance of the steel through electrochemical tests of cyclic potentiodynamic polarization and double-cycle potentiokinetic reactivation (DL-EPR). The heat treatments were performed at 1100° C for 30, 120 and 240 min with subsequent air cooling. The results of the DL-EPR showed that although there was no presence of intermetallic phases even with the absence of intermetallic phases, the solution annealing time influenced the degree of chromium depletion of the samples, so that with the increase of tim...
Journal of Metastable and Nanocrystalline Materials, 1999
This work is characterized by a comparative study of mechanical properties and corrosion resistan... more This work is characterized by a comparative study of mechanical properties and corrosion resistance of alloys in common use and under consideration in orthodontics. The study is being conducted in three types of alloys, stainless steel 304V, Ni-Ti alloy which are the most common, and Ni-Free alloy Böhler latest, in order to compare their behavior with mechanical tension stress intraoral
Journal of Metastable and Nanocrystalline Materials, 2000
Page 1. Materials Science Forum Vols. 343-346 (2000) pp 861-866 © (2000) Trans Tech Publications,... more Page 1. Materials Science Forum Vols. 343-346 (2000) pp 861-866 © (2000) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/JMNM.8.861 All rights reserved. No part of contents of this paper may be reproduced ...
Matéria (Rio de Janeiro), 2008
As indústrias de extração de petróleo e produção de gás têm utilizado de forma crescente os aços ... more As indústrias de extração de petróleo e produção de gás têm utilizado de forma crescente os aços inoxidáveis, por serem ligas que combinam boa propriedade mecânica a resistência à corrosão e são economicamente viáveis, para aplicações em linha de escoamento onshore e offshore. Estes materiais geralmente exibem excelente resistência à corrosão, tenacidade e soldabilidade. Entretanto, de todos os tipos de corrosão, a corrosão de localizada por pite é o processo mais difícil de controlar. O presente trabalho estuda o efeito da taxa de resfriamento na corrosão dos aços inoxidáveis martensíticos 13Cr-4Ni-0,02C e 13Cr-2Ni-0,1C. Foi observado que o aumento da taxa de resfriamento levou a formação de uma microestrutura refinada e com estruturas dendríticas. A taxa de corrosão foi determinada por ensaio de imersão e foi observado que quanto maior a taxa de resfriamento, maior a taxa de corrosão para os aços estudados. A densidade de pite, profundidade de pite e taxa de corrosão foram maiores...
Materials Science Forum, 2014
This proposal aims at structural characterization of Ti-Fe-Si-B alloys produced by high-energy ba... more This proposal aims at structural characterization of Ti-Fe-Si-B alloys produced by high-energy ball milling and subsequent sintering. In this study, quaternary alloys were prepared from raw materials of high purity: Ti (99.9 wt-%), Fe (99.8 wt-%), Si (99.999 wt-%) and B (99.5 wt-%). The milling process of the Ti-2Fe-22Si-11B and Ti-7Fe-22Si-11B (at-%) powders was carried out in a planetary Fritsch P-5 ball mill. Subsequently, the Ti-Fe-Si-B powders milled for 600 min were sintered (1100 ° C for 240 min) under vacuum to obtain equilibrium structures. The characterization of as-milled powders and sintered alloys was performed by means of X-ray diffraction, scanning electron microscopy, and electron dispersive spectrometry. Extended solid solutions were formed during the initial milling times while that the brittle Ti5Si3 phase was formed for longer milling times in both the quaternary powder mixtures. This fact contributed for reducing the particle sizes. Homogeneous samples containin...
Materials Science Forum, 2014
Several cements are used as biomaterials. Biopolymers such as chitosan and collagen exhibit excel... more Several cements are used as biomaterials. Biopolymers such as chitosan and collagen exhibit excellent biocompatibility and can be used in the remodeling of bone tissue. The cement must have high mechanical strength and compatibility with original tissue. In this context, the objective of this study was to extract, characterize and cross-link collagen from bovine tendon, forlater associate it with chitosan and calcium phosphate to obtain cements for bone regeneration. Glutaraldehyde was used as cross-linker in 0.1, 0.5, 1.0 and 10% concentration. Infrared analysis confirmed the presence of functional groups characteristic of collagen, whereas the capacity of water absorption decreased with the increasing of cross-linking degree. Denaturation temperatures of collagen samples were obtained by Differential Scanning Calorimetry and Scanning Electron Microscopy showed the fiber structure characteristics of collagen, which were more organized for high degree of cross-linking samples.
Journal of Non-Crystalline Solids, 2000
Amorphous Fe±M±B (M¸Zr, Nb) based alloys with nanometer-sized crystallites have attracted attenti... more Amorphous Fe±M±B (M¸Zr, Nb) based alloys with nanometer-sized crystallites have attracted attention due to their magnetic properties. Although corrosion resistance is a desirable property in such alloys, no study concerning this aspect has been reported. The eect of metalloid content and partial crystallization on corrosion resistance of Fe±M±B (M¸Zr, Nb) amorphous alloys, Fe 84 Nb 7 B 9 , Fe 84 Zr 7 B 9 and Fe 83 Zr 3X5 Nb 3X5 B 9 Cu 1 , was investigated. Corrosion resistance measurements were carried out by mass loss, potentiodynamic polarization, and thermogravimetric mass gain measurements. The partial crystallization of the amorphous alloy results in a decrease of the corrosion resistance for all the compositions analyzed. We also observed a greater corrosion resistance when Nb was present in comparison to the case when Zr was present. These results are an eect of the super®cial passive ®lm protector formed.
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Papers by Neide Aparecida Mariano Mariano