Korneli Grigoriev Grigorov

Prof. Korneli Grigoriev Grigorov


Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

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

Representative Publications

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22 March 2019 in Micromachines
Verified
Journal Article
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NGNierlly Galvão
Nierlly Galvão
MGMarciel Guerino
Marciel Guerino
TCTiago Campos
Tiago Campos
KGKorneli Grigoriev Grigorov
Korneli Grigoriev Grigorov
Mariana FragaMariana Fraga
Mariana Fraga
HMHomero Maciel
Homero Maciel
Many strategies have been developed for the synthesis of silicon carbide (SiC) thin films on silicon (Si) substrates by plasma-based deposition techniques, especially plasma enhanced chemical vapor deposition (PECVD) and magnetron sputtering, due to the importance of these materials for microelectronics and related fields. A drawback is the large lattice mismatch between SiC and Si. The insertion of an aluminum nitride (AlN) intermediate layer between them has been shown useful to overcome this problem. Herein, the high-power impulse magnetron sputtering (HiPIMS) technique was used to grow SiC thin films on AlN/Si substrates. Furthermore, SiC films were also grown on Si substrates. A comparison of the structural and chemical properties of SiC thin films grown on the two types of substrate allowed us to evaluate the influence of the AlN layer on such properties. The chemical composition and stoichiometry of the samples were investigated by Rutherford backscattering spectrometry (RBS) and Raman spectroscopy, while the crystallinity was characterized by grazing incidence X-ray diffraction (GIXRD). Our set of results evidenced the versatility of the HiPIMS technique to produce polycrystalline SiC thin films at near-room temperature by only varying the discharge power. In addition, this study opens up a feasible route for the deposition of crystalline SiC films with good structural quality using an AlN intermediate layer.

25 February 2022 in Materials
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Journal Article
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COCarlos Alberto Monesi Oliveira
Carlos Alberto Monesi Oliveira
KGKorneli Grigoriev Grigorov
Korneli Grigoriev Grigorov
ATAleksandar Tsanev
Aleksandar Tsanev
AJArmstrong Godoy Junior
Armstrong Godoy Junior
ACAntonio augusto Couto
Antonio augusto Couto
MMMarcos Massi
Marcos Massi
Hexagonal boron-nitride nanoparticle coating was deposited on AISI 1045 steel surface. The deposition process included a transformation of B-containing thin organic film into nanocrystalline BN using two methods: thermal annealing at 450–850 °C and reactive ion etching in Ar/N2 plasma. The film structure, phases, and film morphology of deposited nanoparticles of boron nitride on AISI 1045 steel were characterized by XPS, XRD, and EDS. Post-annealing at 450 °C does not lead to the formation of a BN phase in the layer. A non-stoichiometric BN phase with nitrogen deficiency appears at 650 °C. At 850 °C annealing, the formed BN phase is completely stoichiometric. The effects of deposited and incorporated BN on the friction and hardness properties of AISI 1045 steel were also studied. The post-annealing process improved the hardness from 5.35 to 11.4 GPa, showing a pronounced linear temperature dependence. An original approach was adopted to quantify the energy-dependent growth constants based on the indentation load-discharge curves measured on samples treated under different conditions. Those constants describe the rate of the reactions and the type of interdiffusion process characteristic for each material used. This approach can partially fulfill the role of the Rutherford backscattering spectrometry profile, which is an expensive and time-consuming process, mainly when light elements such as boron and nitrogen are used.

1 September 2025 in Journal of Physics: Conference Series
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Conference Paper
Open access
PTP. Tabakova
P. Tabakova
APA. Petrova
A. Petrova
GAG. Avdeev
G. Avdeev
DSD. Slavov
D. Slavov
MMM. Massi
M. Massi
KGKorneli Grigoriev Grigorov
Korneli Grigoriev Grigorov
Ti-Al-V alloys are mostly used in the aerospace and automotive industries as light material with good strength and elasticity. However, it shows some drawbacks, such as high friction coefficient especially at elevated temperatures, as well as fast oxidation and deterioration of its chemical and crystal structure. Thus, it turns improper its use where the surface properties are of importance. The present study aims to cover this alloy with a protective layer of thickness up to 3 microns with especially pronounced compositional gradient character in order to minimize these drawbacks. The gradient structure is essential to assure a good adherence, especially required at high temperature and stress. The chosen protective coatings are based on Ti-carbo-nitride multilayers (TiCN), providing outstanding hardness, exceeding 30 GPa, while keeping low friction coefficient and excellent adhesion properties even under extreme conditions. The coatings were deposited by Physical Vapor Deposition (PVD). The adhesion is an important quality and the present study shows that near the interface, the both Young's modulus at the adjacent materials are close.

1 January 2024 in Aerospace Research in Bulgaria
Verified
Journal Article
Closed access
ATAleksandar Tsanev
Aleksandar Tsanev
KGKorneli Grigoriev Grigorov
Korneli Grigoriev Grigorov
HKHristo Kolev
Hristo Kolev
ABAnna Bouzekova-Penkova
Anna Bouzekova-Penkova
BTBoyko Tsyntsarski
Boyko Tsyntsarski
DTDimitar Teodosiev
Dimitar Teodosiev