Simona Elena Bejan

Dr. Simona Elena Bejan

National Research and Development Institute for Non-ferrous and Rare Metals - Laboratory of Advanced and Nanostructured Materials
orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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8 January 2021 in Manufacturing Review
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ASAnca Elena Slobozeanu
Anca Elena Slobozeanu
Simona Elena BejanSimona Elena Bejan
Simona Elena Bejan
ITIoan Albert Tudor
Ioan Albert Tudor
AMAna-Maria Mocioiu
Ana-Maria Mocioiu
AMAdrian Mihail Motoc
Adrian Mihail Motoc
CPCristian Predescu
Cristian Predescu
Nanostructured coatings and films play an important role in modern surface engineering due to their ability to improve and optimize materials behavior under different external constraints such as high/low temperatures, stress/strain, corrosive/oxidizing atmosphere, electromagnetic fields/fluxes etc., used practically in all industrial fields. Surface modification may be done using any type of materials: polymers, metals, ceramics, composites or hybrids on any type of substrate by different physical, chemical or combined technologies. Thermal characterization methods are one of the most accessible tools to study, model and predict the process parameters required to preserve the nanostructures during thermal treatment of different coatings, develop novel multi-material coating systems, study the complex correlations between material properties vs. synthesis and processing parameters in real environments. Differential Scanning Calorimetry (DSC) is often used as a standard method to put in evidence different thermal events such as phase transitions, decomposition, oxidation/reduction, nucleation and growth at the substrate/coating interfaces or in coating materials. The present paper aims to review some examples on how DSC may be used to assess the thermal behavior of coatings using standardization tools and developing novel application fields.
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27 October 2020 in Materials
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Cristina Florentina CiobotaCristina Florentina Ciobota
Cristina Florentina Ciobota
RPRoxana Mioara Piticescu
Roxana Mioara Piticescu
CNCiprian Neagoe
Ciprian Neagoe
ITIoan Albert TUDOR
Ioan Albert TUDOR
AMAlexandru Cristian Matei
Alexandru Cristian Matei
Simona Elena BejanSimona Elena Bejan
Simona Elena Bejan
In this work, (Ba0.75Sr0.25) (Ti0.95Co0.05) O3 perovskite nanostructured material, denoted subsequently as Co-doped BaSrTiO3, was synthesized in a one-step process in hydrothermal conditions. The obtained powder was heat-treated at 800 °C and 1000 °C, respectively, in order to study nanostructured powder behavior during thermal treatment. The Co-doped BaSrTiO3 powder was pressed into pellets of 5.08 cm (2 inches) then used for thin film deposition onto commercial Al2O3 substrates by RF sputtering method. The microstructural, thermal, and gas sensing properties were investigated. The electrical and thermodynamic characterization allowed the evaluation of thermodynamic stability and the correlation of structural features with the sensing properties revealed under real operating conditions. The sensing behavior with respect to the temperature range between 23 and 400 °C, for a fixed CO2 concentration of 3000 ppm, highlighted specific differences between Co-doped BaSrTiO3 treated at 800 °C compared to that treated at 1000 °C. The influence of the relative humidity level on the CO2 concentrations and the other potential interfering gases was also analyzed. Two possible mechanisms for CO2 interaction were then proposed. The simple and low-cost technology, together with the high sensitivity when operating at room temperature corresponding to low power consumption, suggests that Co-doped BaSrTiO3 has a good potential for use in developing portable CO2 detectors.

13 September 2021 in Materials
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Journal Article
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BSBeatrice - Adriana Serban
Beatrice - Adriana Serban
IBIoana Cristina Badea
Ioana Cristina Badea
NCNICOLAE CONSTANTIN
NICOLAE CONSTANTIN
Dumitru MitricaDumitru Mitrica
Dumitru Mitrica
MOMihai Tudor Olaru
Mihai Tudor Olaru
Ana Maria Julieta PopescuAna Maria Julieta Popescu
Ana Maria Julieta Popescu
The continuous development of society has increased the demand for critical raw materials (CRMs) by using them in different industrial applications. Since 2010, the European Commission has compiled a list of CRMs and potential consumption scenarios with significant economic and environmental impacts. Various efforts were made to reduce or replace the CRM content used in the obtaining process of high-performance materials. Complex concentrated alloys (CCAs) are an innovative solution due to their multitude of attractive characteristics, which make them suitable to be used in a wide range of industrial applications. In order to demonstrate their efficiency in use, materials should have improved recyclability, good mechanical or biocompatible properties, and/or oxidation resistance, according to their destination. In order to predict the formation of solid solutions in CCAs and provide the optimal compositions, thermodynamic and kinetic simulations were performed. The selected compositions were formed in an induction furnace and then structurally characterized with different techniques. The empirical results indicate that the obtained CCAs are suitable to be used in advanced applications, providing original contributions, both in terms of scientific and technological fields, which can open new perspectives for the selection, design, and development of new materials with reduced CRM contents.


3 September 2020
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Closed access
ASA. Sobețkii
A. Sobețkii
MOM.T. Olaru
M.T. Olaru
UCU. Cindemir
U. Cindemir
LÖL. Österlund
L. Österlund
ASA. Stănoiu
A. Stănoiu
RIR.E. Irimescu
R.E. Irimescu