Basics of Formation of Iron Borid e Coatings

Dybkov, V. I.

doi:10.20941/2414-2115.2016.02.5

Cited by 9 publications

(5 citation statements)

References 38 publications

(76 reference statements)

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“…The Hf 2 Fe peaks point disordered thin clusters of tissuefree Hf-Fe bonds from the surface interlayer of pure Hf. According to the phase diagram, the Hf 2 Fe phase is most likely to form when the percentage of Hf is below 60%, which is achieved by huge abundance of boron only [33].…”

Section: Resultsmentioning

confidence: 99%

Mechanical and tribological characterization of nanostructured HfB2 films deposited from compound target

et al. 2020

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Fabrication and development of HfB 2 -based nanostructured coatings was investigated. All films were deposited on stainless-steel substrates by RF magnetron sputtering from stochiometric HfB 2 target in argon atmosphere. The aim of this work is to evaluate the effects of the bias potential on the microstructure, mechanical and tribological properties. These parameters strongly depend on the experimental conditions. X-ray diffraction analysis indicated the difference in microstructure: from dense hexagonal structure with (0001) preferred orientation of nanocrystallites to quasi-amorphous with blurred HfB 2 phase peaks. All coatings were measured using nanoindentation (using Berkovich tip), tribology (ballon-disk) and nano-scratch (friction). Coatings with a thickness of 1-2 µm had a significant dependence of properties on the microstructure: hardness drastically increased from 8 to 45 GPa, H/E ratio and elastic recovery changed respectively: 0.04-0.15 and 0.26-0.72.

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Section: Resultsmentioning

confidence: 99%

Mechanical and tribological characterization of nanostructured HfB2 films deposited from compound target

et al. 2020

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“…In the particular case of chromium, it can form dispersed and independent chromium borides with a crystal lattice parameter very close to iron borides (iron monoboride and diiron boride) and dissolve in these phases. Due to the ability of chromium to concentrate in the outer part of the double phase (FeB–Fe 2 B) [ 59 ] the high chromium concentration in the substrate of about 13.7%, and the high chemical affinity of chromium with boron (chromium monoboride, chromium diboride, chromium tetraboride, chromium diboride, dichromium triboride, tetrachromium triboride, and pentachromium triboride) [ 25 , 60 ] coupled with the thickness at which the cobalt radiation used can penetrate ranges between 15 and 20 μm, the presence of chromium monoboride and chromium diboride phases in the X-ray analysis is explained. The identification of metal borides depends on their affinity for boron atoms and the selection of boronizing parameters and volume fractions.…”

Section: Resultsmentioning

confidence: 99%

“…Dybkov [ 25 ] conducted a comprehensive study on forming boride coatings on different substrates using two differential equations. Samples of other steels were embedded in a boron-rich mixture containing 5% potassium tetrafluoroborate as an activator (KBF 4 ).…”

Section: Introductionmentioning

confidence: 99%

Analysis of Diffusion Coefficients of Iron Monoboride and Diiron Boride Coating Formed on the Surface of AISI 420 Steel by Two Different Models: Experiments and Modelling

Ortiz-Domínguez,

Morales-Robles,

Gómez-Vargas

et al. 2023

Materials

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In the present work, two mathematical diffusion models have been used to estimate the growth of the iron monoboride and diiron boride coating formed on AISI 420 steel. The boronizing of the steel was carried out with the solid diffusion packing method at a boronizing temperature of 1123 K–1273 K. Experimental results show the two-coating system consists of an outer monoboride and an inner diiron boride coating with a predominantly planar structure at the propagation front. The depth of the boride coating increases according to temperature and treatment time. A parabolic curve characterizes the propagation of the boride coatings. The two proposed mathematical models of mass transfer diffusion are founded on the solution corresponding to Fick’s second fundamental law. The first is based on a linear boron concentration–penetration profile without time dependence, and the second model with time dependence (exact solution). For both models, the theoretical law of parabolic propagation and the average flux of boron atoms (Fick’s first fundamental law) at the growth interfaces (monoboride/diiron boride and diiron boride/substrate) are considered to estimate the propagation of the boride coatings (monoboride and diiron boride). To validate the mathematical models, a programming code is written in the MATLAB program (adaptation 7.5) designed to simulate the growth of the boride coatings (monoboride and diiron boride). The following parameters are used as input data for this computer code: (the layer thicknesses of the FeB and Fe2B phases, the operating temperature, the boronizing time, initial formation time of the boride coating, the surface boron concentration limits, FeB/Fe2B and Fe2B/Fe growth interfaces, and the mass transfer diffusion coefficient of boron in the iron monoboride and diiron boride phases). The outputs of the computer code are the constants εFeB and εFe2B. The assessment of activation energies of AISI 420 steel for the two mathematical models of mass transfer is coincident (QFeB=221.9 kJ∙mol−1 and QFe2B=209.1 kJ∙mol−1). A numerical analysis was performed using a standard Taylor series for clarification of the proximity between the two models. SEM micrographs exhibited a strong propensity toward a flat-fronted composition at expansion interfaces of the iron monoboride and diiron boride coating, confirmed by XRD analysis. Tribological characterizations included the Vickers hardness test method, pin-on-disc, and Daimler–Benz Rockwell-C indentation adhesion tests. After thorough analysis, the energies were compared to the existing literature to validate our experiment. We found that our models and experimental results agreed. The diffusion models we utilized were crucial in gaining a deeper understanding of the boronizing behavior of AISI 420 steel, and they also allowed us to predict the thicknesses of the iron monoboride and diiron boride coating. These models provide helpful approaches for predicting the behavior of these steels.

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“…In a study by Fellner and Chrenkova [41], different carbon-and high-chromium ledeburitic steels were borided in a molten mixture of boron carbide and borax, and achieved very similar outcomes and explanations. In a study by Dybkov [16], steels were borided with different Cr contents and reported a significantly higher chromium content in Fe 2 B than in FeB. In addition to the fact that the Fe 2 B is first enriched by the chromium diffusion from the substrate, the isomorphism of the two phases Fe 2 B and Cr 2 B should be considered [41].…”

Section: Sem Examinations and Eds Analysismentioning

confidence: 99%

“…However, in the case of high-alloy steels, it is difficult to obtain the Fe 2 B layer solely. In this case, the thickness of FeB phase can reach 50% of the total layer thickness [15,16]. In the case of chromium steels, the chromium borides (Cr x B y ) may be present in the boride layers as precipitates [17].…”

Section: Introductionmentioning

confidence: 99%

Characterizations and Kinetic Modelling of Boride Layers on Bohler K190 Steel

Orihel¹,

Jurči²,

Кеддам

2023

Coatings

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In this study, the Bohler K190 steel, manufactured by the powder metallurgy (PM) process, was subjected to the boronizing process. This thermochemical treatment was carried out in the range of 1173 to 1323 K, for 1–10 h. The scanning electron microscopy (SEM) was utilized for examining the morphology of layers’ interfaces with a dual-phase nature and measuring the layers’ thicknesses. The obtained boronized layers had a maximum thickness of 113 ± 4.5 µm. The X-ray diffraction analysis (XRD) confirmed the presence of FeB and Fe2B layers. The energy dispersive spectroscopy (EDS) mapping and EDS point analysis were used to investigate the redistribution of chemical elements within the boronized layers and the transition zone. The values of Vickers microhardness of Fe2B, FeB, and transition zone were estimated. Finally, the boron activation energies in FeB and Fe2B were found to be 204.54 and 196.67 kJ·mol−1 based on the integral method and compared to the literature results.

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Basics of Formation of Iron Borid e Coatings

Cited by 9 publications

References 38 publications

Mechanical and tribological characterization of nanostructured HfB2 films deposited from compound target

Mechanical and tribological characterization of nanostructured HfB2 films deposited from compound target

Analysis of Diffusion Coefficients of Iron Monoboride and Diiron Boride Coating Formed on the Surface of AISI 420 Steel by Two Different Models: Experiments and Modelling

Characterizations and Kinetic Modelling of Boride Layers on Bohler K190 Steel

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