Phase transformation sequence of amorphous ferrochrome alloy electrodeposit

Accepted Manuscript Phase transformation sequence of amorphous ferrochrome alloy electrodeposit Cheng Liu, Lei Jin, Fang-Zu Yang, Zhong-Qun Tian PII:

S0925-8388(18)34578-X

DOI:

https://doi.org/10.1016/j.jallcom.2018.12.031

Reference:

JALCOM 48672

To appear in:

Journal of Alloys and Compounds

Received Date: 13 October 2018 Revised Date:

28 November 2018

Accepted Date: 3 December 2018

Please cite this article as: C. Liu, L. Jin, F.-Z. Yang, Z.-Q. Tian, Phase transformation sequence of amorphous ferrochrome alloy electrodeposit, Journal of Alloys and Compounds (2019), doi: https:// doi.org/10.1016/j.jallcom.2018.12.031. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Phase transformation sequence of amorphous ferrochrome alloy electrodeposit Cheng Liu, Lei Jin, Fang-Zu Yang* *, Zhong-Qun Tian State Key Laboratory of Physical Chemistry of the Solid Surfaces, and Department of Chemistry, College of

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Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China

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ABSTRACT A series of ferrochrome alloy layers with different iron contents are electrodeposited. The phase transformation sequences of the electrodeposited Cr-29.51 wt.% Fe alloy layer upon heat treatment are studied in detail. X-ray diffraction analysis shows that as the iron content of the layer increases, the ferrochrome alloy layer changes from a crystalline structure of a substitutional solid solution, then to a mixed-structure of amorphous and crystalline, and finally to an amorphous structure. The differential scanning calorimetry curves at heating rates ranging from 5 ℃/min to 20 ℃/min, accompanied with the heat treatment, indicate that the layer starts the first crystallization at around 692.45 ~ 722.15 K and then precipitates new phases of Cr2O3 and Cr23C6 at around 870.35 ~ 895.95 K. Their apparent activation energies are 172.1 (Ea1) for the crystallization and 341.6 kJ/mol (Ea2) for the new phase precipitation, respectively. After the heat treatment, the iron content on the surface of the layer is significantly reduced while the O strongly increased. Key words: Ferrochrome alloy, Amorphous, Crystallisation behavior, Phase transformation, Electrodeposition

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1. Introduction Known as iron-base alloy, the amorphous ferrochromium attracts considerable interest because of its excellent corrosion resistance, wear resistance, magnetic property and electro-catalytic property.1 The methods of smelting process and electrodeposition are generally used to prepare the ferrochrome alloy, wherein the electrodeposition method has been widely studied because it is simple and easy to control the alloy metal ratio.2,3,4,5 Wang et al.1 have electrodeposited Fe-Cr alloy films from a trivalent chromium bath containing glycine as complexing agent. They found that the crystallographic structures of deposited films are the α-Fe solid solution with 3.1 at.% Cr, the meta-stable phase with Cr content ranging from 4.5 to 22.4 at.%, and the amorphous structure with Cr content ranging from 22.9 to 74.4 at.%. Jiang et al.2 (our former work) have indicated that Cr–Fe alloys were solid solution structure, which changed from crystalline to amorphous as iron weight content exceeded 26.3%, from a novel trivalent chromium sulphate electrolyte using oxalate as the complexing agent. Amorphous alloy is in a metastable state because of its disordered atomic arrangement and higher free energy. The amorphous state can be transformed from the metastable to a steady state by structural relaxation and crystallization under heat treatments. The previous studies1,2 mainly focused on the preparation and coat characterization of ferrochrome alloy layers. There are few

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2. Experimental procedure

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studies6,7 on the structural changes of amorphous ferrochromium. Karantzalis6 et al. have only speculated the structure of ferrochromium by microstructural observations, while Chernov7 et al. have researched phase transformation of Ferritic–Martensitic 12% Chromium Steels EK-181 and ChS-139. Whereas the phase transformation process of electrodeposited ferrochrome alloy layer has not been reported before. For the guidance of ferrochrome alloy layer in practical application, it is significant to reveal the phase transformation behavior of amorphous ferrochrome alloy layer. In this study, firstly a series of ferrochrome alloy layers with different structures are electrodeposited conveniently by changing the ferrous ion content from a novel Cr3+ solution. We then analyze the composition, structure and surface morphology of the layers in as-coated and after heat treatments using the techniques of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and auger electron spectroscopy (AES). To illuminate the phase transformation sequence and crystallization kinetics of the amorphous ferrochrome alloy layer, we study the phase transformation behavior and apparent activation energies of the amorphous Cr-29.51 wt.% Fe layer by the techniques of differential scanning calorimetry (DSC) and XRD.

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2.1. Electrodeposition Ferrochrome alloy layers of different iron contents with a thickness around 6 µm (measured by X-ray fluorescence thickness gauge (XAN-DPP, Fischer, Germany)) were electrodeposited onto a polished copper sheet substrate in plating solution8, 9 (Table 1) for 30 min. While DSA anode10 (Dimensionally Stable Anode, Ti coated IrO2 anode) was selected as the anode. The solution was prepared using analytically pure reagents and deionised water. All the chemicals were purchased from the Aladdin Industrial Corporation (Shanghai, China). Before the plating, a copper sheet or a mild steel sheet was first degreased for 10 min in a solution containing sodium phosphate (50 g/L), sodium carbonate (50 g/L), sodium hydroxide (10 g/L) and sodium dodecylsulphate (0.2 g/L) at 70 °C; and then activated in 10% (v/v) sulfuric acid at room temperature for 30 s. Electrodeposited metal sheet were washed with deionised water and dried for further analysis. The samples of the Cr-Fe alloy, electrodeposited on the mild steel sheet, were easily peeled off from the substrate and used for the DSC analysis. 2.2. Deposit characterization Heat treatment: Continuous heating under different constant heating rates of 5, 10, 15 and 20 °C/min was performed using a differential scanning calorimeter (DSC 404C, NETZSCH, Germany), which can record the reaction enthalpies of the different steps of the transformation sequence during heating up to 700 °C in air flow. For further analysis of the phase transformation behavior of the layer, samples were heated in the tube furnace (SK-G06123K, Zhonghuan, China) in air flow from room temperature up to 300, 500 and 700 °C for 1 h under a constant heating rate of 10 °C/min. Then the heated samples cooled to room temperature under a constant falling rate of 10 °C/min. Surface morphology: the surface appearance of the deposit was examined using a scanning electron microscope (SIGMA SEM, Zeiss, Germany) operated at an accelerating voltage of 15 kV. Coupled EDS was used to measure the contents of elements. The auger electron spectroscopy

ACCEPTED MANUSCRIPT (PHI 660 AES, Physical electronics, America) measurement was performed at a vacuum of 1 x 10-9 torr, with an acceleration voltage of 5 kV and a beam current of 100 nA. Structural analysis: XRD patterns of the samples in as-coated state and after the heating processes were recorded at room temperature using an X-ray diffractometer (Ultima IV, Rigaku, Japan) with a Cu-Kα source. XRD was performed at scanning angles ranging from 20° to 90° (2θ) with scanning speed of 10°/min and wavelength λ of 0.15406nm.

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Table 1 Solution composition and plating conditions for the plating of Cr-Fe alloy layer Constituents of solution

Quantity

Oxalic acid (H2C2O4·2H2O)

5.0 g/L

Sodium oxalate (Na2C2O4)

5.0 g/L

Chromium sulfate (Cr2(SO4)3·6H2O)

25.0 g/L

Boric acid (H3BO3)

80.0 g/L

Sodium sulfate (Na2SO4)

100.0g/L

Conductive salt

Potassium sulfate (K2SO4)

20.0 g/L

Conductive salt

Ferrous bisglycinate ((NH2CH2COO)2Fe)

0~600.0 mg/L

Complexing agent Complexing agent

Source of Cr3+

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Thiourea (S=C(NH2)2)

Function

60.0 mg/L

Source of Fe2+ Additive

44.0~46.0 ℃

Temperature pH

3.4~3.6

5.0 A/dm2

Current density 3. Results and discussion

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3.1. Preparation and characterization of ferrochrome alloy layers By simply changing the ferrous ion content in the bath, the ferrochrome alloy layers with different iron contents can be obtained by electrodeposition. When the ferrous ion content in the bath is 0, 100, 200, 300 and 600 mg/L, the iron content of the ferrochrome alloy layer electrodeposited for 30 min at 45 °C and 5 A·dm-2 is 0, 9.28%, 21.02%, 29.51% and 45.39%, respectively. Their surface morphologies are shown in Figure 1. The obtained layers all have metallic luster by visual inspection. SEM results show that the ferrochrome alloy layers have the similar grain structures with a clear boundary between the particles. As the iron content of the layer increases, the diameters of the cell-like particles increase significantly ( from 0.8 µm to 4 µm ). Figure 2 shows XRD patterns of ferrochrome alloy layers with different iron content. Without iron (Fig. 2a), a diffraction intensity of 7337 occurs at 2θ of 64.6°, which corresponds to the (200) crystal plane diffraction peak of body-centered cubic chromium. This diffraction peak is sharp, indicating that the chromium layer is a distinct crystalline. Abd et al.11 pointed out that the (110) and (211) crystal faces of Cr correspond to the metal chromium of α phase, while the (200) crystal face corresponds to the metal chromium of γ phase, so the chromium plating layer corresponding to Fig. 2(a) is a crystalline structure of the γ phase. The ferrochrome alloy layer with an iron content of 9.28 wt.% has an XRD pattern (Fig. 2b) similar to that of Fig. 2(a), indicating that the layer also exhibits the crystalline state. Diffraction peak corresponding to the Cr (200) is observed, demonstrating that the ferrochrome alloy layer is a substitutional solid solution in which iron is dispersed in the matrix chromium. Chromium layer

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possesses high internal stress and micro-crack structure12. A small amount of iron substituting chromium causes the decrease of internal stress, behaving that the Fig. 2(a) has a peak broadening compared to Fig. 2(b). It is worth noting that when the iron content of the layer reaches 21.02 wt.%, as shown in Fig. 2(c), the peak intensity of the Cr (200) is significantly weakened, and a diffuse scattering peak with a diffraction intensity of only 373 appears near 44.2° (corresponding to the Cr (110)). It means that the ferrochrome alloy layer exhibits a distinct mixed-structure of amorphous and crystalline. Further, when the iron content of the layer increases to 29.51 wt.% (Fig. 2d) and above (Fig. 2e), the XRD patterns show a diffuse scattering peak only around 44.2° (2θ), and the coatings exhibit amorphous structure characteristics2,13. The above results show that the structure of ferrochrome alloy layer is closely related to its iron content. As the iron content of the layer increases, the ferrochrome alloy layer changes from a crystalline structure of a substitutional solid solution, then to a mixed-structure of amorphous and crystalline, and finally to a distinct amorphous structure. Based on the report of Czagány et al.14, it is supposed that as the iron content increases, the Cr-Cr interfacial bonds are weakened by iron atom, which leads to inhibition of further grain growth. The layer can grow further only due to nucleation of new grains. Thus, the crystal size is inversely proportional to the iron content of the ferrochrome alloy layer, making the layer transform from crystalline structure finally to an amorphous structure. Wang et al.1 indicated that when the chromium content in the ferrochrome alloy layer is in the range of 22.9~74.4 at.%, the layer exhibits an amorphous structure. Jiang et al.2 also reported that the ferrochrome alloy layer changed from a crystalline to an amorphous structure as the iron content increased from 18.3 wt.% to 26.3 wt.%. The results of this paper are consistent with theirs. Therefore it can be seen that by changing the content of ferrous ions in the plating solution, a series of ferrochrome alloy layers with different iron contents and different crystal structures can be prepared.

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Fig.1. SEM image of the Cr-Fe alloy with Fe contents of (a) 0, (b) 9.28, (c) 21.02, (d) 29.51 and (e) 45.39 wt.%

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intensity(a.u.)

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Fig.2. XRD patterns of the Cr-Fe alloy with Fe contents of (a) 0, (b) 9.28, (c) 21.02, (d) 29.51 and (e) 45.39 wt.% 3.2 Phase transformation and structural behavior of the amorphous ferrochrome alloy The amorphous ferrochrome alloy layer with an iron content of 29.51 wt.% was selected for heat treatment to reveal its phase transformation and structural behavior. The DSC heat treatment was conducted to different raising temperatures for understanding the structural transformation details of the deposit. Figure 3 presents the DSC curves for the amorphous structure layer heated up from 350 ℃ to 700 °C at different rates (5, 10, 15 and 20 °C/min). At 5 °C/min, an exothermic peak began in the DSC curve when the heating temperature reached 393.9 °C (667.05 K), and its peak temperature (TP1) was 419.3 °C (692.45 K). The exothermic peak is attributed to the crystallization behavior of the amorphous structure. Besides, when the temperature reached 576.6 °C (849.75 K), another exothermic peak appeared, and the peak temperature (TP2) of the second exothermic peak was 597.2 °C (870.35 K). These crystallization behaviors of amorphous ferrochrome alloy layer at different temperatures can provide a theoretical prediction for the practical application of the alloy layer under controlled ambient temperature. The values of initial exothermic temperature TX and peak temperature TP of the two peaks at different heating rates are listed in Table 2. As the heating rate increases, the onset temperature (TX) and peak temperature (TP) increase. This is a typical dynamics characteristic of the layer undergoing a crystallization process. Considering the variation in the peak temperature (TP) with heating rate, the apparent activation energy (∆E) of amorphous ferrochrome alloy layer is derived using the Kissinger equation in the following form15: ln(γ/T2)=- ∆E/RT+C where γ is the heating rate, ∆E is the activation energy for the crystallization process, R is the

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exo

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universal gas constant, C is a constant, and T is a specific temperature such as the peak or onset temperature. Then, the slope of ln (γ/T2) vs. 1/T plot (Fig. 4) is used to obtain the apparent activation energy from the data in Table 2. The values calculated from the peak temperature of the two apparent activation energies ∆Ea1 and ∆Ea2 are 172.1 (Ea1) and 341.6 (Ea2) kJ/mol, respectively. Ea1
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Fig.3. The DSC curves of the Cr-Fe layer with Fe content of 29.51 wt.% at the heating rates of (a) 5, (b) 10, (c) 15 and (d) 20 ℃/min Table 2 The variation of onset temperature (TX) , peak temperature (TP) at different heating rates

Tx1 (K) 667.05 677.05 680.65 688.45

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γ (℃/min) 5 10 15 20

Tp1 (K) 692.45 708.35 719.45 722.15

Tx2 (K) 849.75 865.35 870.65 876.55

Tp2 (K) 870.35 883.75 889.55 895.95

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∆Ea1=172.1KJ/mol

-11.5

∆Ea2=341.6KJ/mol

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Fig.4. Kissinger plots for determining apparent activation energy of Cr-29.51 wt.% Fe alloy layer

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In order to further clarify the structural changes of the amorphous Cr-29.51 wt.% Fe alloy layer during crystallization process at different temperatures, the coating was heated to 300, 500 and 700 °C for 1 hour, respectively, and then cooled to room temperature. The XRD spectrums of the heated layers are shown in Figure 5. The XRD spectrum of the layer after heat treatment at 300 °C is almost the same as that of the as-plated sample shown in Figure 2d, indicating that the amorphous ferrochrome alloy layer is structurally stable below 300 °C. After heat treatment at 500 °C, three sharp diffraction peaks appeared at 24.5°, 64.7° and 81.9°, respectively, corresponding to the (110), (200) and (211) crystal planes of body-centered cubic chromium11,16. This is consistent with the temperature at which the first peak of crystallization appears in the DSC curve of Figure 3, indicating that the first peak in the DSC curve corresponds to the phase transformation of the layer from an amorphous to crystalline structure. A number of new sharp diffraction peaks appeared in the XRD pattern after heat treatment at 700 °C, which were corresponded to the diffraction peaks of Cr, Cr2O3 and Cr23C6 after compared with the XRD standard card, demonstrating that the new phases have been precipitated after heat treatment. By the heat treatment of Cr-C layer prepared from the trivalent chromium of chloride system, Kwon17 found that the layer transferred from amorphous to crystalline structure when the heat temperature was at 400 °C, and new phases of Cr2O3, Cr7C3 and Cr23C6 were formed at 800 °C. Our works show the similar results.

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♣Cr ♦Cr2O3 ♥Cr23C6

700℃ ♦♥ ♥

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Fig.5. X-ray diffraction patterns of the Cr-Fe alloy layers annealed at different temperature for 1h in air

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3.3 Analysis of surface states The amorphous Cr-29.51 wt.% Fe alloy layer before and after heat treatment at 700 °C for 1 h was subjected to AES analysis to further investigate the surface composition and states of the layer after crystallization, and the results are shown in Figure 6. Results show that the surface elements of the as-plated ferrochrome alloy layer are mainly Cr, Fe and a small amount of O, C and S (Fig. 6a). Among them, C may be derived from the organic compounds of the oxalic acid, oxalate, glycine, etc. in electrolyte during electroplating18, while S from the additive of thiourea, and O from the air oxidation of the layer after plating. Besides, a part of catalytically active chromium ad-atoms may interact with C and S of organic compounds adsorbed on electrode surface, for example: 2Cr0ad + C(IV)→2Cr(II) + C(0) C and S are therefore co-deposited into the layer by abovementioned reaction19. After heat treatment at 700 °C for 1 h, the peaks of Cr, O and C were observed on the surface of the ferrochrome alloy layer (Fig. 6b), and the peak intensity of Fe was significantly weakened. It can be deduced that during the heat treatment, the ferrochrome alloy tends to form chromium carbide and chromium oxide coated surface. The surface morphology of the ferrochrome alloy layer after heat treatment at 700 °C is shown in Figure 7. The surface of the crystallized amorphous Cr-29.51 wt.% Fe alloy layer is clearly covered with fine particles. Obviously, these fine particles correspond to the newly formed chromium carbide and chromium oxide. The surface contents of the Cr-29.51 wt.% Fe alloy, which were in as-plated, heat treated at 500 °C, heat treated at 700 °C, and etched with argon ion for 5 minutes after heat treated at 700 °C, were tested by EDS and the results are shown in Table 3. The results show that the elements of the as-plated and heated alloy surfaces are C, O, S, Cr and Fe. As the temperature increases, the iron content of the alloy surface decreases significantly, whereas the O content strongly increases. This obviously shows that the surface of the alloy forms mainly the oxides during heat treatment in air,

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Kinetic Energy (10 eV)

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Cr2 O2 O1 Cr1

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Fe3 Fe2 Fe1

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Fig.6. AES patterns of the Cr-29.51 wt.% Fe alloy deposits without annealing (a) and with annealing at 700 ℃ for 1 h (b)

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and the oxide is most the chromium oxide. After argon ion etching for 5 minute the iron content of the heat treated alloy at 700 °C is significantly higher than it without etching and is comparable to that of the as-plated alloy. The heat treatment results illustrate that the ferrochrome alloy layer tends to form mainly the chromium oxide and chromium carbide coated surface during heat treatment in air, while surface iron content of the layer is decreased.

Fig.7. SEM image of the Cr-29.51 wt.% Fe alloy annealed at 700 ℃ for 1h in air

As-plated

Element C O

Wt.% 5.33 4.40

At.% 18.18 11.25

Annealed at 500 ℃ Wt.% 7.21 15.28

At.% 19.82 31.53

Annealed at 700 ℃ Wt.% 4.70 38.39

At.% 10.08 61.75

After etching of annealed at 700 ℃ Wt.% At.% 5.32 13.09 26.10 48.20

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2.79 46.14 21.64

1.31 51.11 25.10

1.34 32.46 14.84

0.48 52.29 4.14

0.38 25.88 1.91

1.82 43.65 23.11

1.68 24.80 12.23

Table.3. EDS table of the Cr-Fe alloy with Fe contents of 29.51wt.% annealed at 500 ℃, 700 ℃ for 1h in air and polished (700 ℃)

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4. Conclusions

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This study provides a method for the convenient preparation of a series of ferrochrome alloy layers with different iron contents and structures. The structure is closely related to the iron content of ferrochrome alloy layer. As the iron content of the layer increases, the structures of the ferrochrome alloy layers changes from a crystalline to a mixed-structure of amorphous and crystalline, and finally to an amorphous structure (iron content at 29.51 wt.%). During the heat treatments of the amorphous ferrochrome alloy layer, crystallization behavior occurs at a lower temperature of 500 °C and the new phases precipitate (Cr2O3 and Cr23C6) at a higher temperature of 700 °C. The apparent activation energies are 172.1 KJ/mol (Ea1) for crystallization and 341.6 KJ/mol (Ea2) for new phase precipitation. After heat treatment, the iron content on the surface of ferrochrome alloy is decreased and the Cr2O3 compound is enriched. The phase transformation behavior provides the guidance of the ferrochrome alloys in practical application.

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Acknowledgement The authors gratefully acknowledge the financial support from the National Natural Science Foundation Innovation Group (no. 21621091)

ACCEPTED MANUSCRIPT References 1.

Wang, F.; Watanabe, T., Preparation and characterization of the electrodeposited Fe–Cr alloy film.

Materials Science and Engineering: A 2003, 349 (1-2), 183-190. 2.

Jiang, Y. F.; Yang, F. Z.; Tian, Z. Q.; Zhou, S. M., Effects of iron ion contents on composition,

morphology, structure and properties of chromium coatings electrodeposited from novel trivalent chromium sulphate electrolyte. Transactions of the IMF 2013, 90 (2), 86-91. Protsenko, V.; Danilov, F., Kinetics and mechanism of chromium electrodeposition from formate

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3.

and oxalate solutions of Cr(III) compounds. Electrochimica Acta 2009, 54 (24), 5666-5672. 4.

Survilienė, S.; Nivinskienė, O.; Češunienė, A.; Selskis, A., Effect of Cr(III) solution chemistry on

electrodeposition of chromium. Journal of Applied Electrochemistry 2006, 36 (6), 649-654. 5.

Ferreira, E. S. C.; Pereira, C. M.; Silva, A. F., Electrochemical studies of metallic chromium

electrodeposition from a Cr(III) bath. Journal of Electroanalytical Chemistry 2013, 707, 52-58.

Karantzalis, A. E.; Lekatou, A.; Kapoglou, A.; Mavros, H.; Dracopoulos, V., Phase Transformations

SC

6.

and Microstructural Observations During Subcritical Heat Treatments of a High-Chromium Cast Iron. Journal of Materials Engineering and Performance 2011, 21, 1030-1039.

Chernov, V. M.; Leont’eva-Smirnova, M. V.; Potapenko, M. M.; Polekhina, N. A.; Litovchenko, I. Y.;

M AN U

7.

Tyumentsev, A. N.; Astafurova, E. G.; Khromova, L. P., Structure–phase transformations and physical properties of ferritic–martensitic 12% chromium steels EK-181 and ChS-139. Technical Physics 2016, 61 (1), 97-102. 8.

Yang, F. Z.; Jiang, Y. F.; Xu, S. K.; Yao, S. B.; Chen, B. Y.; Huang, L.; Tian, Z. Q.; Zhou, S. M.; Trivalent

chromium plating in sulphate bath and method. CN Patent 101665960A, 2010. 9.

Yang, F. Z.; Jiang, Y. F.; Xu, S. K.; Yao, S. B.; Chen, B. Y.; Huang, L.; Tian, Z. Q.; Zhou, S. M.; Anode of

10.

TE D

trivalent chromium plating. CN Patent 101665974A, 2010.

Li, B.; Lin, A.; Wu, X.; Zhang, Y.; Gan, F., Electrodeposition and characterization of Fe–Cr–P

amorphous alloys from trivalent chromium sulfate electrolyte. Journal of Alloys and Compounds 2008, 453 (1-2), 93-101.

11. Abd El Rehim, S. S.; Ibrahim, M. A. M.; Dankeria, M. M., Thin Films of Chromium

EP

Electrodeposition from a Trivalent Chromium Electrolyte. Transactions of the IMF 2017, 80 (1), 29-33. 12. Andersson, M.; Högström, J.; Urbonaite, S.; Furlan, A.; Nyholm, L.; Jansson, U., Deposition and characterization of magnetron sputtered amorphous Cr–C films. Vacuum 2012, 86 (9), 1408-1416. yanov, V. I.; Pushkarev, E. S.;

AC C

13. Dorofeev, G. A.; Lubnin, A. N.; Ulyanov, A. L.; Kamaeva, L. V.; Lad

Shabashov, V. A., XRD characterization of mechanically alloyed high-nitrogen nanocrystalline Fe–Cr system. Materials Letters 2015, 159, 493-497. 14. Czagány, M.; Baumli, P.; Kaptay, G., The influence of the phosphorous content and heat treatment on the nano-micro-structure, thickness and micro-hardness of electroless Ni-P coatings on steel. Applied Surface Science 2017, 423, 160-169. 15.

Kissinger, H. Reaction Kinetics in Differential Thermal Analysis. Analytical Chemistry 1957, 29,

1702-1706. 16. Ghaziof, S.; Golozar, M. A.; Raeissi, K., Characterization of as-deposited and annealed Cr–C alloy coatings produced from a trivalent chromium bath. Journal of Alloys and Compounds 2010, 496 (1-2), 164-168. 17. Kwon, S. C.; Kim, M.; Park, S. U.; Kim, D. Y.; Kim, D.; Nam, K. S.; Choi, Y., Characterization of intermediate Cr-C layer fabricated by electrodeposition in hexavalent and trivalent chromium baths.

ACCEPTED MANUSCRIPT Surface and Coatings Technology 2004, 183 (2-3), 151-156. 18. Edigaryan, A. A.; Safonov, V. A.; Lubnin, E. N.; Vykhodtseva, L. N.; Chusova, G. E.; Polukarov, Yu. M., Properties and preparation of amorphous chromium carbide electroplates. Electrochimica Acta 2002, 47, 2775-2786. 19.

Protsenko, V. S.; Gordiienko, V. O.; Danilov, F. I., Unusual "chemical" mechanism of carbon

co-deposition in Cr-C alloy electrodeposition process from trivalent chromium bath. Electrochemistry

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Communications 2012, 17, 85-87.

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Highlights:
A series of ferrochrome alloy are prepared by changing the Fe2+ content in the bath
During the heat treatment, the layer undergoes a crystallization process
Surface composition of the layer changes after heat treatment