Romeu Chelariu

@tuiasi.ro

Department of Materials Science/Faculty of Materials Science and Engineering
Gheorghe Asachi Technical University of Iasi

Romeu Chelariu


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https://researchid.co/romiche

RESEARCH INTERESTS

metallic materials, metallic biomaterials, non-ferrous alloys, microstructure, corrosion, mechanical properties
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Scopus Publications

Scopus Publications

  • ANALYSIS OF THE CORROSION RATE OF FeMn-Si BIODEGRADABLE MATERIAL
    Archives of Metallurgy and Materials, 2022
  • New zn3mg-xy alloys: Characteristics, microstructural evolution and corrosion behavior
    Catalin Panaghie, Ramona Cimpoeșu, Bogdan Istrate, Nicanor Cimpoeșu, Mihai-Adrian Bernevig, et al.
    Materials, 2021
    Zinc biodegradable alloys attracted an increased interest in the last few years in the medical field among Mg and Fe-based materials. Knowing that the Mg element has a strengthening influence on Zn alloys, we analyze the effect of the third element, namely, Y with expected results in mechanical properties improvement. Ternary ZnMgY samples were obtained through induction melting in Argon atmosphere from high purity (Zn, Mg, and Y) materials and MgY (70/30 wt%) master alloys with different percentages of Y and keeping the same percentage of Mg (3 wt%). The corrosion resistance and microhardness of ZnMgY alloys were compared with those of pure Zn and ZnMg binary alloy. Materials were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), linear and cyclic potentiometry, and immersion tests. All samples present generalized corrosion after immersion and electro-corrosion experiments in Dulbecco solution. The experimental results show an increase in microhardness and indentation Young Modulus following the addition of Y. The formation of YZn12 intermetallic phase elements with a more noble potential than pure Zinc is established. A correlation is obtained between the appearance of new Y phases and aggressive galvanic corrosion.
  • Electrochemical analysis and in vitro assay of Mg-0.5Ca-xY biodegradable alloys
    Bogdan Istrate, Corneliu Munteanu, Stefan Lupescu, Romeu Chelariu, Maria Daniela Vlad, et al.
    Materials, 2020
    In recent years, biodegradable Mg-based materials have been increasingly studied to be used in the medical industry and beyond. A way to improve biodegradability rate in sync with the healing process of the natural human bone is to alloy Mg with other biocompatible elements. The aim of this research was to improve biodegradability rate and biocompatibility of Mg-0.5Ca alloy through addition of Y in 0.5/1.0/1.5/2.0/3.0wt.%. To characterize the chemical composition and microstructure of experimental Mg alloys, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), light microscopy (LM), and X-ray diffraction (XRD) were used. The linear polarization resistance (LPR) method was used to calculate corrosion rate as a measure of biodegradability rate. The cytocompatibility was evaluated by MTT assay (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide) and fluorescence microscopy. Depending on chemical composition, the dendritic α-Mg solid solution, as well as lamellar Mg2Ca and Mg24Y5 intermetallic compounds were found. The lower biodegradability rates were found for Mg-0.5Ca-2.0Y and Mg-0.5Ca-3.0Y which have correlated with values of cell viability. The addition of 2–3 wt.%Y in the Mg-0.5Ca alloy improved both the biodegradability rate and cytocompatibility behavior.
  • Corrosion behavior of some timonb alloys in ringer solution
    Maria Magdalena Pricopi, Romeu Chelariu, Nicolae Apostolescu, Doina-Margareta Gordin, Daniel Sutiman, et al.
    Revista De Chimie, 2020
    The aim of this study was to investigate the influence of different process parameters as chemical composition, the pH value and immersion time on the corrosion of the some TiMoNb alloys, using different electrochemical techniques such as: cyclic voltammetry, open circuit potential (OCP) measurement, polarization curves and electrochemical impedance spectroscopy (EIS). The alloys were analyzed in the natural pH of the Ringer solution, but also with an acidic modification of the solution (ph = 4) and a basic modification (ph = 8). The more acidic values of pH, the more evident are differences between corrosion behavior of titanium-based alloys depending on their chemical compositions and immersion times.
  • Electrochemical evaluation of some Mg-Ca-Mn-Zr biodegradable alloys
    Bogdan Istrate, Corneliu Munteanu, Romeu Chelariu, Dumitru Mihai, Ramona Cimpoesu, et al.
    Revista De Chimie, 2019
    Biodegradable magnesium alloys represent a class of materials with high properties that are used in a wide range of fields, such as medicine, aeronautics and automotive. Alloying the Mg-based alloys with small percentages of elements such as Ca, Mn and Zr can conduct to the obtaining of some materials that can be the basis for the development of orthopedic implants. Calcium contributes to the formation of the Mg2Ca lamellar compound, low concentrations of zirconium helps the microstructure refinement and corrosion resistance and the alloying with manganese leads to the increase of the mechanical characteristics.In this paper, the electrochemical behaviour of four biodegradable alloys from the Mg-Ca-Mn-Zr system was evaluated, with variable concentrations (0.5% -1%) of Mn, respectively Zr. Alloying the system with 1% of each element (Ca, Mn, Zr) led to the obtaining of the alloy with the highest corrosion resistance and the lowest degradation rate.
  • Corrosion behavior of new quaternary ZrNbTiAl alloys in simulated physiological solution using electrochemical techniques and surface analysis methods
    R. Chelariu, L.C. Trinca, C. Munteanu, G. Bolat, D. Sutiman, et al.
    Electrochimica Acta, 2017
    The potential biomedical application of three new quaternary Zr alloys, namely Zr6Ti15Nb4Al, Zr32Ti15Nb4Al, and Zr49Ti15Nb4Al, was evaluated in vitro using electrochemical methods complemented with surface analysis of corrosion resistance. Cyclic potentiodynamic polarization (CCP) and electrochemical impedance spectroscopy (EIS) tests were performed in Ringer’s solution at 37 °C. The electrochemical behavior of the ZrTiNbAl quaternary alloys was consistent with the formation of passivating oxide films on the surfaces of these materials. Localized breakdown of the oxide layer occurred on Zr6Ti15Nb4Al and Zr32Ti15Nb4Al alloys subjected to positive anodic polarization, a feature confirmed by scanning electron microscopy (SEM) on retrieved samples. The Zr49Ti15Nb4Al alloy, which had the highest titanium (49 wt.%) content, exhibited a larger passive range in the polarization curve and was immune to localized corrosion breakdown in a simulated physiological solution for the range of polarizations that can occur in the human body.
  • Investigations on composites reinforced with HEA particles
    I Carcea, R Chelariu, L Asavei, N Cimpoeşu, R M Florea
    Iop Conference Series Materials Science and Engineering, 2017
    This work reports the results of investigations on the fortification with high entropy alloys particles of aluminium matrix composite materials. The properties of these materials processed by Vortex techniques primarily depend on the matrix and the volume fraction of the constituent phase. The mechanical properties, toughening mechanisms and potential applications are briefly reviewed. Traditional methods were used for the basic characterization of the composite. The microstructure of the composites were investigated by optical and scanning electron microscopy (OM, SEM). SEM analysis was performed in order to observe the microstructural evolution as a function of the HEA particles content and to identify some reasons of the presence of porosity or any irregularities within the metal matrix.
  • Study on wear resistance fenicrmnal high entropy alloy - Mechanical properties
    Gheorghe Buluc, Romeu Chelariu, Gabriela Popescu, Mihail Sârghi, Ioan Carcea
    Key Engineering Materials, 2017
    Traditional alloys is based on a single element called matrix and to improve some mechanical properties (strength, ductility, strength) are added and other metallic elements in the system. High entropy alloys have become a field of increasingly explored in the world of materials. Excellent mechanical properties obtained of the high entropy alloys recommend them to be from year to year as investigated. In the last decade more than 500 high entropy alloys journal and conference papers have been published [1]. High entropy alloys are alloys who have in their composition 5 to 13 metal elements and the concentration of each component is between 5% and 35%. These elements in the composition of high entropy alloys are divided into elements of minority and majority elements. They are called minority elements because their molar fraction is less than 5%. High entropy alloys have mixing entropy higher than traditional alloys, ΔScons≥1.61R (R = 8.314 J / (mol • K)) [1]. High entropy alloy have been obtained in the laboratory of Science and Materials Engineering faculty from Iasi using a medium frequency induction furnace with 8000 Hz. Because they have excellent mechanical properties high entropy alloys can be used in various fields with high wear and corrosion degree or electronic, magnetic applications [1]. In this work we selected pure metallic elements like: Fe, Ni, Cr, Mn and Al. The quantity of alloy developed varied between 0.5 and 1.5 kg. Metal load necessary for the preparation of metal alloys were formed technical grade, industrial accessible prices and satisfying. Friction and wear rezistance were studies by using a reciprocating sliding test machine , in a pin on disk configuration, using aluminum as counter face.In this paper it investigated the wear resistance of high entropy alloys obtained, microstructure and their mechanical properties.
  • Prediction of corrosion resistance of some dental metallic materials applying artificial neural networks
    D. Mareci, G. D. Suditu, R. Chelariu, L. C. Trincă, S. Curteanu
    Materials and Corrosion, 2016
    Numerous studies have been done on the corrosion process of different dental metallic materials, especially using a comparative method and analyzing the electrochemical phenomena. Simultaneously, the effects of the corrosion process have been quantify by different physical quantities, such as corrosion rate, corrosion resistance, polarization resistance, corrosion current density etc. These experimental data can be used to model the corrosion process and, subsequently, to perform predictions with the aim to analyze or to control the process. In this work, a series of experimental data about corrosion of some titanium-based dental materials in artificial saliva were obtained through electrochemical impedance spectroscopy (EIS) tests and used as a database to develop a model of corrosion process by artificial neural networks. The process parameters taken into account were chemical compositions of the materials (cp–Ti, NiTi, NiTiNb), immersion time, pH, NaF content, and albumin content. The corrosion resistance of the metallic materials was evaluated by polarization resistance determined by EIS tests. Neural networks were developed and applied for evaluating the corrosion resistance of the alloys, depending on the process parameters. The predictions provided by the model are useful to understand the contribution of each parameter in the process and possible ways to control it.
  • Investigation of the mechanical properties of FeNiCrMnSi high entropy alloy wear resistant
    G Buluc, I Florea, R Chelariu, G Popescu, I Carcea
    Iop Conference Series Materials Science and Engineering, 2016
    In this paper we investigated microstructure, hardness and wear resistance for FeNiCrMnAl, high entropy alloy. The FeNiCrMnSi, high entropy alloy was elaborated in a medium induction furnace, by choosing the silicon, as an alliance element within the equi- atomic high entropy alloy, we managed to obtain a dendritic structure, the formation of intermetallic compounds or separated silicon. The medium hardness value of the investigated alloy was 948.33 HV and the medium value of the friction coefficient was 0.6655 in the first 20 seconds and 0.5425 for 1667 seconds. The volume loss of the high entropy alloy FeNiCrMnSi was 0.0557 mm3.
  • The assessment of erosive potential of some acid beverages on indirect-restorative materials
    Revista De Chimie, 2016
  • Modelling the influence of pH, fluoride, and caffeine on the corrosion resistance of TiMo alloys by artificial neural networks developed with differential evolution algorithm
    D. Mareci, E.-N. Dragoi, G. Bolat, R. Chelariu, D. Gordin, et al.
    Materials and Corrosion, 2015
  • Investigation of processing effects on the corrosion resistance of Ti20Mo alloy in saline solutions
    G. Bolat, J. Izquierdo, T. Gloriant, R. Chelariu, D. Mareci, et al.
    Corrosion Science, 2015
  • Electrochemical characterization of surface modification for Ti6Al7Nb implants with hydroxyapatite-zirconia nanoparticles synthesis by ultrasound irradiations
    R. Chelariu, D. Mareci, G. Bolat, C. A. Peptu, D. Cailean
    Materials and Corrosion, 2015
  • Prediction of Corrosion Resistance of Some Dental Metallic Materials with an Adaptive Regression Model
    Romeu Chelariu, Gabriel Dan Suditu, Daniel Mareci, Georgiana Bolat, Nicanor Cimpoesu, et al.
    JOM, 2015
  • Electrochemical characterization of Ti12Mo5Ta alloys in contact with saline medium
    Daniel MARECI, Romeu CHELARIU, Adrian CAILEAN, Florin BRINZA, Georgiana BOLAT, et al.
    Transactions of Nonferrous Metals Society of China English Edition, 2015
  • Influence of the casting conditions on the structure and properties of a Co-Cr-Mo dental alloy
    Revista De Chimie, 2015
  • The estimation of corrosion behavior of new TiNbTaZr alloys for biomedical applications
    A. C. Bărbînţă, D. Mareci, R. Chelariu, G. Bolat, C. Munteanu, et al.
    Materials and Corrosion, 2014
  • Comparative electrochemical characterization of plasma sprayed zirconia and alumina coatings on titanium substrate
    Journal of Optoelectronics and Advanced Materials, 2014
  • Metastable beta Ti-Nb-Mo alloys with improved corrosion resistance in saline solution
    R. Chelariu, G. Bolat, J. Izquierdo, D. Mareci, D.M. Gordin, et al.
    Electrochimica Acta, 2014
  • A new severe plastic deformation method by repetitive extrusion and upsetting
    L. Zaharia, R. Comaneci, R. Chelariu, D. Luca
    Materials Science and Engineering A, 2014
  • A comparative analysis of new Ti-Nb-Zr-Ta orthopedic alloys
    Andreea Carmen Bărbînţă, Romeo Chelariu, Marcelin Benchea, Carmen Iulia Crimu, Sorin Iacob Strugaru, et al.
    Advanced Materials Research, 2014
  • Electrochemical behavior of new experimental TiNbZrAl alloys for dental applications
    L. A. Dragan-Raileanu, R. Chelariu, D. Mareci, C. Munteanu
    Materials and Corrosion, 2014
  • Electrochemical behaviour of experimental Ti30Ta alloy in the presence of fluoride and albumin protein
    Digest Journal of Nanomaterials and Biostructures, 2014
  • Electrochemical behaviour of Ti alloys containing Mo and Ta as β-stabilizer elements for dental application
    Daniel MARECI, Romeu CHELARIU, Georgiana BOLAT, Adrian CAILEAN, Viorel GRANCEA, et al.
    Transactions of Nonferrous Metals Society of China English Edition, 2013