scholarly journals Solubility of boron and carbon in γ-iron of Fe-B-C alloys

2019 ◽  
Vol 27 (1) ◽  
pp. 31-36
Author(s):  
N. Yu. Filonenko ◽  
A. N. Galdina
Keyword(s):  
Phase Composition ◽  
Boron Content ◽  
Vertical Section ◽  
State Diagram ◽  
Solidification Process ◽  
Weight Fraction ◽  
Solubility Limit ◽  
Maximum Weight ◽  
X Ray ◽  
First Time

It is known that solubility of elements affects the phase composition of alloys that are formed in the solidification process. To predict the phase composition of alloys, it is necessary to determine the solubility limit in the phases. In the paper the structural properties of austenite of alloys in the system of Fe-B-C are studied and the solubility limit of boron and carbon is determined. The investigation is carried out for the specimens with carbon content of 0.0001–2.3 wt.% and boron content of 0.0001–1.0 wt.%, the rest is iron. To determine the physical properties of alloys, we use the microstructure analysis, X-ray microanalysis, X-ray structure analysis and differential thermal analysis. It is shown experimentally that the maximum shift of the eutectoid point is observed when boron content is up to 0.004 wt.%. When boron content of the alloy increases to 0.01 wt.%, the eutectoid point shifts to the left to 0.21 wt.%-carbon and the austenite area decreases. Further increase in the numerical value of boron content in the alloy is hardly caused the eutectoid point to shift. In this paper, the vertical section of the Fe-B-C system state diagram is obtained from experimental data. For the first time we obtain temperature dependence of the free energy of γ-iron solid solution, using the quasi-chemical method, and determine the solubility limit of carbon and boron. The maximum weight fraction of boron in the austenite can be up to 0.0136 wt.%, and that for carbon – up to 1.12 wt.%.

scholarly journals Solubility of Boron and Carbon in Ferrite of the Fe-B-C System Alloys

2019 ◽  
Keyword(s):  
Solid Solution ◽  
Carbon Content ◽  
Mass Fraction ◽  
Room Temperature ◽  
Boron Content ◽  
Solubility Limit ◽  
Content Increase ◽  
X Ray ◽  
First Time ◽  
Structure Imperfection

Investigation was carried out for Fe-B-C alloys with carbon content of 0.0001–0.01 % (wt.) and boron content of 0.0001–0.01 % (wt.), the rest is iron. To determine the structural state of alloys we use the microstructure analysis, X-ray microanalysis and X-ray structure analysis. The level of microstraines, dislocation density and the coercive force of ferrite is determined, and it is shown that structure imperfection grows with boron content increase in the alloy. The obtained results enable to suggest that boron atoms in a solid solution of α-iron occupy substitutional-interstitial positions depending on boron content. In the paper it is shown experimentally, that at room temperature solubility limit of boron and carbon in the ferrite is 0.00012 % (wt.) and 0.006 % (wt.). When boron and carbon content increases further, the following phases are formed: Fe2B, Fe3(CB) and Fe23(CB)6. In this paper by means of quasi-chemical method we obtain for the first time temperature dependence of the free energy for α-iron solid solution, as well as solubility limit of carbon and boron. Maximum mass fraction of carbon may be up to 0.016 % (wt.), and maximum boron mass fraction – up to 0.00025 % (wt.). At room temperature the boron solubility limit in ferrite is 0.0001 % (wt.), and carbon one is 0.004 % (wt.). The calculated numerical values of the solubility of boron and carbon in ferrite of the Fe-B-C system alloys are less than that of the experimental results. This can be explained by the fact that boron atoms interact more actively with structure imperfections than carbon atoms. At high temperatures the solubility of carbon and boron in given phase increases.

scholarly journals Structural State and Thermodynamic Stability of Fe-B-C Alloys

2019 ◽  
Vol 20 (4) ◽  
pp. 437-444 ◽  
Author(s):  
N.Yu. Filonenko ◽  
A. N. Galdina ◽  
А.I. Babachenko ◽  
G.A. Kononenko
Keyword(s):  
Phase Composition ◽  
Carbon Content ◽  
Thermodynamic Stability ◽  
Short Range ◽  
Thermodynamic Potential ◽  
Boron Content ◽  
Liquidus Surface ◽  
Temperature Expansion ◽  
High Temperature Expansion ◽  
First Time

The studies were performed for the specimens of Fe-B-C alloys with boron content of 0.005–7.0 wt.% and carbon content of 0.4–5.5 wt.%, the rest was iron. As a result of the experiment carried out in this work, the phase composition and phase transformations occurring in the alloys are investigated and the liquidus surface is constructed; it is shown that the point with minimum temperature of 1375 K at the liquidus surface is observed at boron content of 2.9 wt.% and carbon content of 1.3 wt. %. For the first time, considering the contribution of the first degree approximation of high-temperature expansion of thermodynamic potential into the Gibbs energy of Fe-B-C melt, we obtain the surface of thermodynamic stability of Fe-B-C melt, depending on temperature and content of boron and carbon in the alloy. The findings show that in order to obtain the homogeneous Fe-B-C melt, which does not contain micro-inhomogeneous structures in the form of short-range microregions, it is necessary to perform overheating more than to 150 K.

scholarly journals Calcium Oxalates in Lichens on Surface of Apatite-Nepheline Ore (Kola Peninsula, Russia)

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 656 ◽  
Author(s):  
Frank-Kamenetskaya ◽  
Ivanyuk ◽  
Zelenskaya ◽  
Izatulina ◽  
Kalashnikov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Composition ◽  
Kola Peninsula ◽  
Metabolic Activity ◽  
X Ray ◽  
Calcium Oxalates ◽  
Essential Questions ◽  
First Time ◽  
Scanning Electron

The present work contributes to the essential questions on calcium oxalate formation under the influence of lithobiont community organisms. We have discovered calcium oxalates in lichen thalli on surfaces of apatite-nepheline rocks of southeastern and southwestern titanite-apatite ore fields of the Khibiny peralkaline massif (Kola Peninsula, NW Russia) for the first time; investigated biofilm calcium oxalates with different methods (X-ray powder diffraction, scanning electron microscopy, and EDX analysis) and discussed morphogenetic patterns of its formation using results of model experiments. The influence of inorganic and organic components of the crystallization medium on the phase composition and morphology of oxalates has been analyzed. It was shown that, among the complex of factors controlling the patterns of biogenic oxalate formation, one of the main roles belongs to the metabolic activity of the lithobiont community organisms, which differs significantly from the activity of its individuals.

scholarly journals Effect of Carbon on the Physical and Structural Properties of Boride Fe2B

2016 ◽  
Vol 17 (2) ◽  
pp. 251-255
Author(s):  
N.Yu. Filonenko ◽  
O.M. Galdina
Keyword(s):  
Carbon Content ◽  
Structural Properties ◽  
Boron Content ◽  
Lattice Strain ◽  
Solubility Limit ◽  
Carbon Doping ◽  
Iron Boride ◽  
Carbon Solubility ◽  
X Ray ◽  
Fe2b Phase

For Fe-В and Fe-В-С system alloys one of the structure constituent is iron boride Fe2B but in the literature there is no information on carbon solubility limit in iron boride Fe2В. The object of this paper is to reveal the effect of carbon on the physical and structural properties of boride Fe2В. Investigation was performed for the specimens with carbon content of 0,05 - 0,80 % (wt.) and boron content of 9,0 - 15,0 % (wt.), the rest is iron. To determine the physical properties of alloys we use microstructure analysis, X-ray microanalysis and X-ray structural analysis. It is found that carbon doping of boride Fe2В leads to a feeble lattice strain and effects on the physical characteristics of boride. We estimate the free energy of boride Fe2B and carbon content in Fe2B phase. Carbon can substitute up to 3 – 8 % of boron atoms in Fe2B phase depending on the temperature which is verified by experimental data. The carbon solubility in this phase is also examined.

scholarly journals Thermodynamic Functions of Fe3B Borides

2019 ◽  
Vol 20 (2) ◽  
pp. 139-143
Author(s):  
N.Yu. Filonenko ◽  
O.M. Galdina ◽  
A.V. Kochenov
Keyword(s):  
Diffraction Analysis ◽  
Thermodynamic Functions ◽  
Boron Content ◽  
Liquidus Line ◽  
Complete Suppression ◽  
X Ray Diffraction ◽  
Cast State ◽  
X Ray ◽  
Eutectic Colony ◽  
First Time

In this work we study the structural properties of hypoeutectic and hypereutectic Fe-B alloys, depending on the temperature of heating above the liquidus line and the cooling rate. Experiments were carried out for the Fe-B system alloys with boron content of 2.0 - 4.5 % (wt.), the rest is iron. To determine physical properties of the alloys microstructural and X-ray diffraction analysis were used. It is shown that overheating of the molten alloy to 150 K above the liquidus line and aftercooling leads to complete suppression of the formation of primary iron crystals in the hypoeutectic alloys and partially to suppression of Fe2B formation in the hypereutectic alloys of the Fe-B system. For the first time it is shown that heating of Fe-B hypoeutectic alloys to 150 K above the liquidus line and cooling with a rate of 103 K/s lead to formation of Fe3B boride in as-cast state, which was present in the eutectic colony.

scholarly journals Solubility of carbon, manganese and silicon in γ-iron of Fe-Mn-Si-C alloys

2020 ◽  
Vol 21 (3) ◽  
pp. 525-529
Author(s):  
N. Y. Filonenko ◽  
O. I. Babachenko ◽  
G. A. Kononenko ◽  
K. G. Domina
Keyword(s):  
Free Energy ◽  
Solubility Limit ◽  
Chemical Dependence ◽  
Magnesium Doping ◽  
X Ray ◽  
Contraction Ratio ◽  
Iron Based ◽  
Two Phases ◽  
First Time ◽  
Maximum Content

The study was performed on alloys with a carbon content of 0,37-0,57 % (wt.), silicon 0,23-0,29 % (wt.), manganese 0,7-0,86 % (wt.), the rest– iron. To determine the phase composition of alloys used microstructural, microanalysis and X-ray analysis. In addition, the physical characteristics of the alloys studied in this paper were determined, such as alloy chemical dependence of extension and contraction ratio, impact toughness and hardness. The results obtained in this paper showed that the iron-based alloy with the content of carbon of 0.57 % (wt.), silicon of 0.28 % (wt.) and manganese of 0.86 % (wt.)) had the superior microstructure and physical properties. It was determined that after a number of crystallization and phase transformation the alloy phase structure includes two phases: a-iron and cement magnesium doping Fe2.7Mn0,3C.. For the first time using the method quasichemistry received an expression of the free energy of a γ-iron alloyed with silicon and magnesium, and determined the solubility limit of carbon, manganese and silicon. The maximum content in γ-iron can reach: carbon 6,8 % (at.), manganese – 67,5 % (at.), silicon – 2,3 % (at.).

scholarly journals Phase composition of cathodic deposits synthesized in flinak-k2taf7-kbf4 melt

2003 ◽  
Vol 39 (1-2) ◽  
pp. 261-267 ◽  
Author(s):  
O.V. Makarova ◽  
L.P. Polyakova ◽  
E.G. Polyakov ◽  
A.A. Shevyryov ◽  
A.V. Arakcheeva
Keyword(s):  
Phase Composition ◽  
Current Density ◽  
Boron Content ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Cathodic Potential ◽  
X Ray ◽  
Cathodic Deposits

The phase composition of cathodic deposits synthesized from FLINAK-K2TaF7-KBF4 melt has been studied by the X-ray diffraction method. It is shown that boron content in the electrodeposit grows as the cathodic potential is increased from peak R1 to peak R4 in the voltammogram. The scheme of changes in the phase composition depending on the increasing current density is given as follows: {?-Ta + Ta2B}R1 ? {?-Ta + (Ta3B4 TaB)}R2 ? {TaB2}R3 ? {TaB2 + B}R4.

scholarly journals Solubility of Carbon, Manganese and Silicon in α-Iron of Fe-Mn-Si-C Alloys

2020 ◽  
Keyword(s):  
Solid Solution ◽  
Free Energy ◽  
Solubility Limit ◽  
Chemical Dependence ◽  
X Ray ◽  
Contraction Ratio ◽  
Iron Based ◽  
Two Phases ◽  
First Time ◽  
Maximum Content

The study was performed on alloys with a carbon content of 0.37-0.57% (wt.), silicon 0.23-0.29% (wt.), manganese 0.7‑0.86% (wt.), the rest– iron. To determine the phase composition of alloys used microstructural, microanalysis and X-ray analysis. In addition, the physical characteristics of the alloys studied in this paper were determined, such as alloy chemical dependence of extension and contraction ratio, impact toughness and hardness. The results obtained in this paper showed that the iron-based alloy with the content of carbon of 0.57 % (wt.), silicon of 0.28 % (wt.) and manganese of 0.86 % (wt.)) had the superior microstructure and physical properties. It was determined that after a number of crystallization and phase transformation the alloy phase structure includes two phases: a-iron and cement magnesium dopingFe2.7Mn0,3C. For the first time using the method quasi-chemistry received an expression of the free energy of a solid solution α-iron alloyed with silicon and magnesium, and determined the solubility limit of carbon, manganese and silicon. In δ-iron may dissolve to 0.09% (wt.) carbon, manganese up to 3.5% (wt.), silicon – 0.25% (wt.). The maximum content in α-iron can reach: carbon – 0.017% (wt.), manganese – 21% (wt.), silicon – 1.3% (wt.).

X-ray microanalysis of thin specimens in the transmission electron microscope at voltages up to 1000 Kv.

1978 ◽  
Vol 36 (1) ◽  
pp. 540-541
Author(s):  
G. Cliff ◽  
M.J. Nasir ◽  
G.W. Lorimer ◽  
N. Ridley
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Present Series ◽  
Constant Independent ◽  
X Ray ◽  
Transmission Electron ◽  
Series Of Experiments ◽  
Image Position ◽  
X Ray Absorption

In a specimen which is transmission thin to 100 kV electrons - a sample in which X-ray absorption is so insignificant that it can be neglected and where fluorescence effects can generally be ignored (1,2) - a ratio of characteristic X-ray intensities, I1/I2 can be converted into a weight fraction ratio, C1/C2, using the equationwhere k12 is, at a given voltage, a constant independent of composition or thickness, k12 values can be determined experimentally from thin standards (3) or calculated (4,6). Both experimental and calculated k12 values have been obtained for K(11<Z>19),kα(Z>19) and some Lα radiation (3,6) at 100 kV. The object of the present series of experiments was to experimentally determine k12 values at voltages between 200 and 1000 kV and to compare these with calculated values.The experiments were carried out on an AEI-EM7 HVEM fitted with an energy dispersive X-ray detector.

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

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