Гірничі машини і енергетика ГЕОІНЖЕНЕРІЯ, вип. 7.

2022
Mining machines and energy GEOENGINEERING, iss. 7. 2022

DOI: 10.20535/2707-2096.7.2022.267607
УДК 621.793.7
A. Karpechenko, Cand. Sci. (Tech.), Assoc. Prof.
ORCID: 0000-0002-7543-4159
М. Bobrov*, Cand. Sci. (Tech.), Assistant Lecturer
ORCID: 0000-0002-9098-6912
Admiral Makarov National University of Shipbuilding, Nikolayev, Ukraine
O. Lymar, Cand. Sci. (Phys.–Math.), Assistant Lecturer
ORCID: 0000-0002-0301-7313
Mykolaiv National Agrarian University Mykolaiv, Ukraine
*Corresponding author: laborantmtm@gmail.com
Received 19.05.2022; Accepted 22.06.2022

ELECTRIC ARC COATINGS WITH A COMPLEX OF IMPROVED PROPERTIES FOR

REPAIRING AND HARDENING OF MINING MACHINE PARTS

Purpose. Research and analysis of the possibilities of using electric arc coatings with
improving properties in the repair of machines and mechanisms for mining industry.
Methodology. The porosity of the obtained electric arc coatings was studied using computer
metallography. The hardness was determined on a Vickers-type device. The thermophysical
properties of the coatings were studied using the dynamic calorimeter method. The adhesion
strength of the coatings to the substrate was determined by the method of "pulling the pin".
Determination of wear resistance was carried out on the SMC-2 friction machine according to
the "roller-block" scheme in conditions of limited lubrication. The determination of coherent x-
ray scattering regions to estimate the size of the substructure of the coating material was
carried out by x-ray diffraction analysis on the DRON-3 installation.
Results. An electric arc sprayer has been improved, which makes it possible to improve the
quality of composite coatings by increasing the particle velocity in a high-temperature
heterophase jet and reducing its opening angle, which leads to an increase in the CMM during
spraying from 0.63 to 0.74. At the same time, the increase in the hardness of the metal matrix
in the composite electric arc coating is 21%, their adhesion strength to the base increases by
26%, wear resistance is 6.9 times compared to the unfilled coating. The optimal amplitude-
frequency parameters of the electric pulse action during electric arc spraying of the SV-08G2S
wire (pulse frequency – 6.5 kHz, amplitude – 5 kV) are determined, which provide an increase
in hardness up to 35%, adhesion strength to the substrate up to 30% and wear resistance of
coatings 1.7 times due to grinding and acceleration of the sprayed particles. The optimal
temperature-time parameters of pre-recrystallization heat treatment are established, which
provide a further increase in the hardness of coatings due to the grinding of subgrains to the
nanoscale size inclusive. The possibility of thermal stabilization of the polygonization
substructure of electric arc coatings obtained by spraying 12X18N10T wire by their additional
plastic deformation is shown.
Originality. The electric arc coating method was further developed by improving the design
of the spray head, which made it possible to increase the material utilization rate during their
spraying and physical and mechanical, as well as operational properties. The regularities of
the influence of electric pulse action on the microstructure and physical and mechanical
properties (hardness, density, adhesion strength, thermal conductivity, wear resistance) of
electric arc coatings are established. The process of pre-crystallization treatment of sprayed
coatings in the direction of thermal stabilization of the polygonization substructure due to
subsequent deformation of the obtained coatings was further developed.
Findings and practical implications. The application of the research results obtained in this
work provides an opportunity to expand the range of cheaper sprayed materials for coating

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with increased physical, mechanical and operational properties on heavily loaded parts of
mechanical engineering, electrical products and parts of the military-industrial complex.
Keywords: electric arc composite coatings, electric pulse action, heat treatment.

INTRODUCTION

Formulation of the problem. Equipment used in the mining industries is subject to extreme
mechanical stresses: it has to operate in challenging climatic environments, yet has to work reliably
with an operational lifespan frequently measured in decades. Maintenance of equipment is a vital
consideration in all areas of the mining industry, where high mechanical stresses and the reliance on
aging equipment can quickly impact asset availability. The cost of downtime is significant, and that
of unplanned downtime even more so. Any necessary repairs frequently extend far beyond the single
component that failed, with an unexpected failure often being the cause of damage to other
components with the machinery further increasing costs.
The operational properties of parts and mechanisms, as well as their working time, are determined
mainly by the physical and mechanical properties of the surface. As the statistical analysis shows, the
majority of machines (85...90%) fail not due to breakage, but as a result of wear of the surfaces of
individual parts. In practice, there are various ways to solve the problem of wear of parts of mining
equipment, but the most profitable and promising is the deposition of protective coatings on the
working surfaces.
Analysis of recent research. Most commonly use welding techniques (cladding) for deposition
wear and erosion resistant coatings for repairing and strengthening of worn parts and mechanisms for
mining industry. So, in work [1] use laser cladding for deposition WC-Fe composite coatings; authors
[2] proposed use iron–chromium based hardfaced coatings deposited by shielded metal arc welding
(SMAW); metal active gas (MAG) welding for deposition of NiCrBSi hardfacing alloy reinforced
with tungsten carbide [3]; non-vacuum electron beam cladding for boride reinforced steel coatings
[4]. However, cladding methods have some disadvantages like: high heat-affected zone and welding
distortions, limitations by substrate materials, next machining operation is required and high
equipment cost. Recently, thermal spraying has been increasingly used for deposition wear and
abrasion-resistant coatings. As for mining industry most commonly use high velocity oxygen-fuel
(HVOF) method for Reverse Circulation hammers [5]; convential plasma [6] and supersonic plasma
spraying of cermet coating [7]; detonation spraying of hard composite coatings [8]. It should be noted
that among all these thermal spray methods, electric arc spraying is differs by simplicity and
manufacturability, high productivity, energy efficiency, and material utilization factor. The relative
cost of electric arc coatings is 3...10 times lower than those obtained by other methods while ensuring
their high strength. However, electric arc coatings deposited by convention spraying technologies do
not always provide a sufficient level of physical, mechanical and operational properties necessary for
the efficient operation of parts and mechanisms under specified conditions in mining industry, which
is due to their high level of porosity, low bond strength, hardness and wear resistance.
Analysis of the effectiveness of modern methods of increasing the physical, mechanical and
operational properties of electric arc coatings shows that the main result of their application is mainly
to provide high energy parameters of sprayed particles and reduce their size, as well as to develop
new compositions of composite coatings. Recently, the most promising methods are those that use
pulsed action on the deposition process, in particular, mechanical, acoustic, electrical, laser, etc. [9],
[10]. Among them, it should be noted the use of electrical impulse exposure, which is characterized
by low power consumption and low cost of additional equipment [11].
In addition, the results of recent studies [12], [13], [14], [15] indicate the possibility of expanding
the range of materials from which the electric arc coating is formed and a significant increase in their
physical, mechanical and operational properties.
Also, one of the ways to improve the properties of sprayed coatings is the use of further pre-
recrystallization heat treatment, the essence of which is to fix the polygonization substructure by
cooling the coating material at the stage of formation of nanoscale subgrains [16], [17], [18].

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However, the low speed of particles when using the traditional method of spraying does not always
provide a sufficient degree of their deformation for the manifestation of the "size effect".
The aim of the work is to study and analyze the possibilities of using electric arc coatings with
improving properties in the repair of machines and mechanisms for mining industry.

MAIN PART

To study and analyze the possibilities of using new restorative composite electric arc coatings in
the repair of various kinds of machines and mechanisms, as well as technical means, their spraying
was carried out using a KDM-2 installation, which includes an EM-14M electric arc apparatus.
On the basis of calculations of the optimal gas-dynamic and geometric parameters of the ejector,
which is used for applying electric arc composite coatings [12] and with the help of which the
possibility of uninterrupted supply of powders of various materials to the high-temperature zone of
the atomizer was substantiated, the design of the atomizing head of the EM-14M apparatus was
changed. This made it possible for the first time to form a composite metal-polymer, metal-ceramic
and metal-glass coating due to the use of powders of the corresponding materials in free form.
The developed device for electric arc spraying of composite (multicomponent) coatings has a
number of disadvantages: when the powder is supplied, a significant part of it falls on the periphery
of the initial section of the jet, which worsens the heating of the powder particles and reduces their
speed; there are restrictions on powder consumption when feeding it due to atmospheric injection; a
large opening angle of a high-temperature jet leads to a decrease in the utilization rate of the material,
especially when spraying on parts of the "shaft" type. The listed disadvantages negatively affect the
quality of sprayed composite arc coatings and the content of powder particles in the structure of the
resulting coating.
To eliminate the above disadvantages, changes were made to the design of the device for
uninterrupted powder supply, which made it possible to increase the utilization rate of the material
when spraying a composite electric arc coating and to improve its quality.
An experiment was carried out to establish and compare the characteristics of the developed
devices. Using a device for uninterrupted powder supply [9] and an improved design of the cap of the
spray head of the EM-14M electric arc apparatus [19], a composite metal-glass electric arc coating
was obtained from the composition Sv-08G2S - A-glass (broken glass). Spraying in the first and
second cases was carried out in the following technological mode: current 120 A, voltage 25 V,
compressed air pressure 0.6 MPa, spraying distance 100 mm. The A-glass powder had a fraction of
40...50 microns and was supplied to the high-temperature zone of the atomizer only due to
atmospheric injection. The diameter of the used wire grade Sv-08G2S was 1.2 mm.
Table 1 shows the comparative characteristics of the developed devices designed for the
uninterrupted supply of powders.
As can be seen from Table 1, the jet opening angle decreased by 33%, the spray spot diameter by
28%. The study of the oxygen content in the composite electric arc coating using spectral analysis on
a scanning electron microscope REMMA102-02 showed that its content increased from 0.46 to 0.80
wt. % (+ 74%). The maximum glass phase content also increased from 19.5 to 22.3 vol.% (+ 14%).
The average size of metal particles decreased by 31%, while their speed increased by 19%, and the
temperature remained almost at the same level (an increase of 0.15%), which led to a twofold decrease
in porosity and an increase in the material utilization rate from 0.63 to 0.74.
It was also found that in the obtained metal-to-glass coatings, the microhardness Hμ50 and the
hardness HV5 of the metal matrix made of Sv-08G2S wire increases due to the additional work
hardening created by the glass filler. The microhardness Нμ50 in metal-glass electric arc coatings
increased by an average of 14%, the hardness HV5 - 21%.

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Table 1 - Comparative characteristics of devices for uninterrupted powder supply

Advanced
Powder feeder Indicators
Characteristic Powder
[6] in%
Feeder [16]
Jet opening angle, degrees 9 6 -33
Spray spot diameter, mm 32 23 -28
Particle speed, m / s 89 106 +19
Temperature of metal particles, °С 2064 2067 +0,15
Average particle size, μm 64…76 43…54 -31
Oxygen content in the coating, wt.
0,46 0,80 +74
%
Coating porosity, vol. % 6 3 -50
A-glass content, vol. % 19,5 22,3 +14
CMM 0,63 0,74 +17

The adhesion strength to the base increased from 28 MPa to 38 MPa when 11 ± 3% (vol.) A-glass
was introduced into the Sv-08G2S electric arc coating. An increase in adhesion strength is due to the
fact that non-melted A-glass particles in the coating, colliding with the surface of the base,
additionally activate it due to their high kinetic energy and angular shape, and when colliding with
already fixed plastic metal particles, they "drive" them into the microroughness of the surface
foundations and subsequent layers.
Analysis of the results of studying the wear resistance of metal-glass coatings with A-glass content
from 5 to 17% (vol.) Showed that a coating with 17% (vol.) Of the glass phase has 8 times less wear
than bronze of the BrAZh 9-4 brand after heat treatment (39...41 HRC), but at the same time there is
a catastrophic wear of the counterbody. The most optimal wear resistance has a pair with a metal-
glass coating, with a glass phase content of 11% (vol.), The total wear of which is 6.9 times lower
than that of a pair with an unfilled coating of Sv-08G2S and 2.8 times less than a bronze one.
Thus, an improved device for the uninterrupted supply of free-form powders makes it possible to
control, over a wider range, the content of powder particles in a high-temperature jet and, accordingly,
in a composite electric arc coating. Improves the quality of the resulting coating by increasing the
speed of particles in a high-temperature jet and decreasing the angle of its opening, which leads to an
increase in the utilization rate of the material during spraying and an increase in the hardness of the
metal matrix in the composite electric arc coating, and an increase in their adhesion to the base and
wear resistance.
On the basis of a set of theoretical and experimental studies, we have developed and brought to
practical application the technological foundations of electric arc spraying of coatings using an
electric pulse effect on a heterophase high-temperature flow, which make it possible to obtain a finer
and more dense structure in the coating material with a complex of improved physical, mechanical
and operational properties.
When developing the technological foundations of coating deposition, the optimal amplitude-
frequency parameters of the electric pulse effect during the electric arc spraying of Sv-08G2S wire
(pulse frequency 6.5 kHz, amplitude 5 kV) were determined, which ensure a decrease in the average
size of the sprayed particles from 84 μm to 54 μm an increase in their average flight speed by 20%
due to the intensification of the grinding process and the provision of additional kinetic energy in an
external electric field, which in turn leads to a decrease in porosity from 6% to 3%, the thermal
conductivity coefficient by 12% and an increase in the hardness of coatings by 35 %. As a result of
determining the operational properties, it was found that the use of an electric pulse effect at optimal
parameters provides an increase in the adhesion strength of electric arc coatings made of Sv-08G2S
wire by 30%, and their wear resistance increases by 1.7 times [14], [20].
In works [13], [15], [16], [17], [18], it is noted that it is advisable to carry out pre-recrystallization
heat treatment (PHT) of sprayed coatings to further increase their physical, mechanical and

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operational properties, based on fixing polygonization processes at the stage of the minimum subgrain
size, by heating the material coatings to the temperature of the beginning of primary recrystallization,
short-term exposure and subsequent rapid cooling to room temperature.
It is known [16] that at high degrees of deformation, a "cellular" dislocation structure and bulk
dislocation plexuses of "cell walls" with a thickness of a fraction of a micron are formed. When
heated, three-dimensional walls flatten and turn into flat low-angle subboundaries, and cells into
subgrains. After further short-term exposure of the sprayed coatings at the temperature of the onset
of primary recrystallization and cooling them in air, polygonization processes occur. Due to the high
density of dislocations in the sprayed coatings, a large number of subgrains are formed, that is,
substructural elements are formed, which can have nanoscale dimensions, which leads to an increase
in the physicomechanical properties (in particular, the hardness) of the coatings.
To obtain subgrains (nanograins), which provide the "size effect", it is necessary to fix the moment
of their largest amount with a minimum size, that is, to stop the polygonization process by cooling
the coating material to ambient temperature in order to prevent the processes of collective
polygonization.
The amount of deformation determines the degree of substructure refinement. The larger the
deformation value, the smaller the subgrain size. On the basis of the above experimental studies, it
has been established that the use of electric impulse action during electric arc spraying leads to an
increase in the speed of the sprayed particles and, as a consequence, to an increase in their
deformation. The deformation values of the sprayed particles upon impact on the base and subsequent
layers of the electric arc coating are about 80...95%, and the cooling rate of the deformed particle can
reach 108 deg/s. This high cooling rate prevents dynamic recrystallization processes in the coating
material, which means that work-hardening is maintained. Therefore, a very urgent task is to study
the effect of pre-recrystallization heat treatment on the physicomechanical and operational properties
of electric arc coatings applied with the use of electric pulse action.
Samples of electric arc coatings applied using electric impulse action in the optimal mode (see
above) were obtained, which were heated in a furnace to a temperature close to the beginning of the
initial recrystallization of the coating material obtained from wire of the Sv-08G2S grade, which is
400...450 °C and kept for some time, as shown in Fig. 1.

Figure 1 - Hardness of electric arc coatings obtained from wire of the Sv-08G2S brand:
а - applied in the traditional way; b, c - using electrical impulse action

According to the presented data, it has been established that the value of the hardness of electric
arc coatings increases after pre-recrystallization heat treatment at a temperature of 450 °C and an
exposure of 2 min for a coating applied by traditional technology from 2 GPa to 2.6 GPa. For a coating
applied using an electrical impulse exposure, holding for 1 min at a temperature of 400 °C provides
a maximum hardness value, which increased from 2.7 GPa to 3 GPa (+ 12%).

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From the obtained results of determining the hardness (Fig. 1), it follows that for coatings
deposited with the use of an electric pulse, the optimal mode of pre-recrystallization heat treatment,
which provides the maximum hardness, shifts to the range of lower temperatures and exposures and
makes it possible to increase the hardness by 12%. This dependence is explained by a higher degree
of deformation of particles during the formation of a coating due to an increase in their speed.
The analysis of microstructures showed that no changes in the structure of the coatings before and
after heat treatment were revealed. This indicates that the strengthening effect is provided by
structural elements, the size of which is less than 0.5 μm, which is explained by the resolution of the
human eye and optical microscope.
It is known [16] that when the structure is refined and nanosized elements are obtained, the thermal
conductivity of the metal material decreases. Therefore, we conducted a study of the effect of pre-
recrystallization heat treatment on the thermal conductivity coefficient of the resulting electric arc
coatings. The analysis of the results obtained indicates a decrease in the coefficient of thermal
conductivity of coatings by an average of 15% after pre-recrystallization heat treatment, which is
explained by an increase in the number of boundaries between subgrains.
To quantify the effect of pre-recrystallization heat treatment on the substructure of electric arc
coatings, we determined the sizes of coherent scattering regions (CSR) of X-ray radiation (Table 2).
Table 2 - Size of areas of coherent scattering of X-ray radiation in arc coatings
Spraying technology and CSR size,
Coating Heat treatment
particle deformation nm
Obtained by traditional Without processing >200
technology.
Electric arc coating 450 °С, 2 min 106
Deformation 83%.
applied from wire
Obtained using electrical impulse Without processing ~200
grade Sv-08G2S
exposure.
Deformation 87%. 400 °С, 1 min 87
According to the data given in table. 2, when using an electric pulse during deposition, a decrease
in the areas of coherent scattering of X-rays is observed, which is explained by the refinement of the
substructure in the coating material, since it is known that the CSR size is identified with the average
subgrain size [16], [17], [18]. After further pre-recrystallization heat treatment of electric arc coatings,
the CSRs have significantly lower values compared to heat-treated coatings obtained by traditional
technology. So the CSR of an electric arc coating decreases from 106 nm to 87 nm. Thus, the analysis
of the data obtained suggests that carrying out pre-recrystallization heat treatment makes it possible
in a number of cases to obtain a subgrain structure of a nanoscale size. This is explained by the fact
that after the thermal treatment of the coatings sprayed with the use of an electric pulse effect,
subgrains of a smaller size are formed due to the greater degree of particle deformation.
The main disadvantage of pre-recrystallization heat treatment is a short holding time of several
minutes; therefore, it is urgent to study the possibility of fixing the polygonization substructure of the
sprayed coating and ensuring a longer holding during pre-recrystallization heat treatment due to
subsequent deformation.
For the research, we chose electric arc coatings obtained from wire 12X18H10T, since previous
experiments showed that this material is characterized by a high increase in hardness after pre-
recrystallization heat treatment [16]. The spraying was carried out according to the traditional
technology and with the use of electric impulse action at optimal conditions. The subsequent
deformation of the coating was carried out on a hydraulic press at a load of 20 tons. The amount of
deformation was 15%. The obtained samples with coatings were heated in a furnace to the
temperature of the onset of the primary recrystallization of the material of the electric arc coating
obtained from wire 12Kh18N10T, which is 600 °C. The optimal mode of pre-recrystallization heat
treatment was determined by hardness indicators. The hardness measurement results are shown in
Fig. 2. The hardness of the coating after spraying, applied according to the traditional technology,
was 2.4 GPa. With the use of electric impulse action, the hardness of the coating increased to 2.8
GPa.

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Figure 2 - Dependence of the hardness of electric arc coatings from wire 12X18H10T
sprayed by different technologies on the exposure time during heat treatment:
a - after spraying using traditional technology; c - spraying + deformation (15%);
b - after spraying with the use of electric impulse action; d - spraying + deformation (15%)
Analysis of the data presented shows that the use of subsequent deformation provides a smaller
decrease in hardness with an increase in the holding time during the pre-recrystallization heat
treatment of coatings up to 20 min. This trend is observed for both methods of applying electric arc
coatings. So, for example, the hardness of a coating sprayed by the traditional method, with an
increase in the holding time from 5 min to 20 min without additional deformation, decreases from 3.2
GPa to 2.8 GPa (13%), and after deformation only from 3.9 GPa to 3.8 GPa (-3%). When using an
electro-pulse effect on the spraying process, an increase in hardness is observed after additional
deformation and heat treatment (holding for 20 minutes) by 83%, and when spraying without an
electro-pulse effect - by 58%. This effect is explained by an increase in the deformation value of
particles due to an increase in their average flight speed.
The microstructures of the coatings after the pre-recrystallization heat treatment are shown in Fig.
3. Analysis of microstructures showed that the coating sprayed with the use of electric pulse action is
characterized by the presence of thinner lamellas.

а b
Figure 3 - Microstructure of sprayed electric arc coatings made of 12X18H10T wire after
subsequent deformation and pre-recrystallization heat treatment in a mode that provides
maximum hardness: a - by traditional technology; b - using electrical impulse exposure

Both microstructures have a flaky structure typical of thermal gas coatings. The porosity of the
coating when spraying using the traditional technology is about 6%, when using an electric pulse it
is 4%. Structural elements providing the manifestation of the size effect are not observed. To identify

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them, OCD was determined. The results of determining the CSR of the obtained coatings are given
in table 3.

Table 3 - Size of the OKR of electric arc coatings obtained from wire of grade 12X18H10T
Coating Treatment CSR, nm
After spraying >200
After heat treatment (5 min, 600 °C) 153
Sputtered on After heat treatment (20 min, 600 °C) >200
traditional technology Deformation 15% 164
Deformation 15% and heat treatment (5 min, 600 °C) 87
Deformation 15% and heat treatment (20 min, 600°C) >200
After spraying >200
After heat treatment (5 min, 600 °C) 123
Sputtered using
After heat treatment (20 min, 600 °C) >200
electrical impulse
Deformation 15% 154
action
Deformation 15% and heat treatment (5 min, 600 °C) 82
Deformation 15% and heat treatment (20 min, 600 °C) 198
Both microstructures have a flaky structure typical of thermal gas coatings. The porosity of the
coating when spraying using the traditional technology is about 6%, when using an electric pulse it
is 4%. Structural elements providing the manifestation of the size effect are not observed. To identify
them, OCD was determined. The results of determining the CSR of the obtained coatings are given
in table. 3.
According to the data presented, as in the case of spraying wire Sv-08G2S, coatings sprayed with
the use of electric impulse action are characterized by a lower value of the CSR and nanoscale size.
Heat treatment for 20 min of the re-deformed coatings provides a finer substructure than coatings
after spraying. This is explained by the fact that when repeated deformation is carried out, from 50 to
75% of dislocation interactions ends with the emergence of dislocation barriers (Hirt, Lomer-
Cottrell), the rest is involved in the formation of dislocation tangles. These dislocation barriers,
appearing along the direction perpendicular to the deformation axis, restrain the movement of
dislocations and, as a consequence, reduce the mobility of polygonization subboundaries, thus
inhibiting the polygonization process, providing a stabilizing effect.

CONCLUSIONS and prospects of further research

The improved electric arc atomizer allows improving the quality of coatings by increasing the
particle velocity in the high-temperature heterophase jet and decreasing its opening angle, which leads
to an increase in the material utilization factor during spraying from 0.63 to 0.74 and an increase in
the hardness of the metal matrix in the composite electric arc metal-glass coating on 21%, and as a
result, to increase their adhesion strength to the base by 26%, wear resistance by 6.9 times in
comparison with unfilled coating. Subsequent pre-recrystallization heat treatment of electric arc
coatings applied using an electric pulse effect provides an increase in hardness by an average of 13%
in comparison with similar heat-treated coatings applied by the traditional method, and the use of
additional deformation (15%) makes it possible to increase the holding time to 20 min by reducing
mobility of polygonization subboundaries.
The conducted research and analysis of the possibilities of improving the physical, mechanical
and operational properties of electric arc coatings make it possible to recommend their use at the level
with plasma coatings in the repair of machine parts and mechanisms, as well as other technical means.
Prospects for further research are in the optimization of spraying modes, deformation and heat
treatment, as well as in the development of technologies for the automated application and processing
of the resulting electric arc coatings on specific parts of machines and mechanisms for their effective
operation under specified conditions.

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REFERENCES

[1] Qi Xiao, Wen lei Sun, Kai xinYang et. al., ″Wear mechanisms and micro-evaluation on WC
particles investigation of WC-Fe composite coatings fabricated by laser cladding″, Surface and
Coating Technology, vol. 420, 2021.
https://doi.org/10.1016/j.surfcoat.2021.127341
[2] Vernon E. Buchanan, ″Solidification and microstructural characterisation of iron–chromium
based hardfaced coatings deposited by SMAW and electric arc spraying″, Surface and Coatings
Technology, vol. 203, issue 23, pp. 3638-3646, 2009.
https://doi.org/10.1016/j.surfcoat.2009.05.051
[3] E. Badisch, M. Kirchgaßner, ″Influence of welding parameters on microstructure and wear
behaviour of a typical NiCrBSi hardfacing alloy reinforced with tungsten carbide″, Surface and
Coatings Technology, vol. 202, issue 24, pp. 6016-6022, 2008.
https://doi.org/10.1016/j.surfcoat.2008.06.185
[4] D. A. Santana, G. Y. Koga, W. Wolf, I. A. Bataev, A. A. Ruktuev, C. Bolfarini, C. S. Kiminami,
W. J. Botta, A. M. Jorge Jr, ″Wear-resistant boride reinforced steel coatings produced by non-
vacuum electron beam cladding″, Surface and Coatings Technology, vol. 386, 2020.
https://doi.org/10.1016/j.surfcoat.2020.125466
[5] C. Schulz, T. Schläfer, E. Charrault, et al., ″Erosive Wear Testing of Laser Clad and HVOF
Coatings for Drilling in Mining″, Journal of Thermal Spray Technology, vol. 29, pp. 520–529,
2020. https://doi.org/10.1007/s11666-020-00985-z
[6] H. Zhu, H. Li, ″Microstructure Evolution of Thermally Sprayed TiB2-Ni Cermet Coating:
Comparison Between APS and HVOF Process″, Journal of Thermal Spray Technology, 28, 535–
543 (2019). https://doi.org/10.1007/s11666-018-0809-9
[7] Kai Chong, Yong Zou, Dongting Wu, Yingwen Tang, Yongang Zhang, ″Pulsed laser remelting
supersonic plasma sprayed Cr3C2-NiCr coatings for regulating microstructure, hardness and
corrosion properties″, Surface and Coatings Technology, vol. 418, 2021.
https://doi.org/10.1016/j.surfcoat.2021.127258
[8] V. Y. Ulianitsky, I. S. Batraev, D. K. Rybin, et al., ″Detonation Spraying of Cr3C2-NiCr Coatings
and Their Properties″, Journal of Thermal Spray Technology, vol. 31, pp. 598–608, 2022.
https://doi.org/10.1007/s11666-021-01301-z
[9] V. A. Royanov, V. I. Bobikov, ″Influence of a pulsating spray jet on the structure and
microhardness of coating particles during electric arc metallization″, Reporter of the Priazovskyi
State Technical University, no. 20, pp. 172–175, 2010.
[10] A. F. Ilyushchenko, A. I. Shevtsov, V. A. Okovity, G. F. Gromyko, Processy formirovaniya
gazotermicheskih pokrytij i ih modelirovanie. Minsk: Belarus. Navuka, 2011.
[11] M. Kadyrmetov, ″Research of plasma spray application and strengthening of coatings and ways
of quality management of plasma coating″, Kuban State Agrarian University, no. 8, pp. 1–8,
2012.
[12] O. M. Duboviy, A. A. Karpechenko, S. M. Shumov, ″Appliances for Electric arc spraying″,
83603 Ukraine IPC C23C 4/00, № a 2007 07157, Jul. 25, 2008
[13] O. M. Duboviy, T. A. Yankovets, A. A. Karpechenko, O. O. Zhdanov, ″Coating method″, 88755
Ukraine IPC С23С 4/18, №. a 2009 02658, Nov. 10, 2009.
[14] A. N. Dubova, A. A. Karpechenko, M. N. Bobrov, ″Improvement of electric-arc and plasma
coating performance by electric pulse impact on two-phase high-temperature flow″, Automatic
Welding, № 8 (734). рр. 39-43. 2014.
http://dspace.nbuv.gov.ua/handle/123456789/103490
[15] A. N. Dubovoj, A. A. Karpechenko, M. N. Bobrov and Yu. E. Nedelko, ″Formation of
nanodimensional polygonization substructure in sprayed electric arc coatings″, Automatic
Welding, №3(762), pp. 40-43, 2017.
[16] O. M. Dubovyy, A. A. Karpechenko, M. M. Bobrov, O. O. Zhdanov, T. O. Makrukha, and Yu.
E. Nedelko, ″Formation of Polygonization Nanoscale Substructure and Its Impact on the Physical

70
Гірничі машини і енергетика ГЕОІНЖЕНЕРІЯ, вип. 7. 2022

and Mechanical Properties of Metals, Alloys, and Sprayed Coatings″, Metallofizika i Noveishie
Tekhnologii, vol. 39, no. 2, pp. 209-243, 2017.
https://doi.org/10.15407/mfint.39.02.0209
[17] O. M. Dubovyy, A. A. Karpechenko, M. M. Bobrov, and A. V. Labartkava, ″Development of
Thermal Spray Technology of Forming a Crushed Polygonization Nanosized Substructure″,
Metallofizika i Noveishie Tekhnologii, vol. 42, no. 5, pp. 631-653, 2020.
https://doi.org/10.15407/mfint.42.05.0631
[18] O. M. Dubovyy, A. A. Karpechenko, M. M. Bobrov, A. V. Labartkava, Yu. E. Nedelko, and O.
O. Lymar, ″Increase of Physical-Mechanical and Operational Properties of Electric Arc and
Plasma Sprayed Coatings by the Formation of a Thermally Stable Ground and Nanosize
Substructure″, Metallofizika i Noveishie Tekhnologii, vol. 41, no. 4, pp. 461-480, 2019.
https://doi.org/10.15407/mfint.41.04.0461
[19] O. M. Dubovyi, A. A. Karpechenko, M. M. Bobrov, A. O. Mazurenko, ″ Device for electric arc
spraying of composite coatings″, 111760 Ukraine IPC C23C 4/131, № a 2014 07318, Jun.10,
2016
[20] O. M.Dubovyi, O. V. Chechel, M. M. Bobrov, Yu. Ye. Nedel'Ko, ″Perspectives of improving
physical and mechanical properties of thermal coatings by electropulse exposure″, Naukovyi
Visnyk Natsionalnoho Hirnychoho Universytetu, №1, pp. 82-87, 2017.
http://nbuv.gov.ua/UJRN/Nvngu_2017_1_15

А. А. Карпеченко, к.т.н., доц.

ORCID: 0000-0002-7543-4159
М. М. Бобров*, к.т.н., асист.
ORCID: 0000-0002-9098-6912
Національній університет кораблебудування
імені адмірала Макарова, м. Миколаїв, Україна,
А. А. Лимарь, к.ф-м.н., асист.
ORCID: 0000-0002-0301-7313
Миколаївський національний аграрний університет,
м. Миколаїв, Україна
*Відповідальний автор: laborantmtm@gmail.com
Подана 19.05.2022; Прийнята 22.06.2022

ЕЛЕКТРОДУГОВІ ПОКРИТТЯ З
КОМПЛЕКСОМ ПІДВИЩЕНИХ ВЛАСТИВОСТЕЙ
ДЛЯ ВІДНОВЛЕННЯ ТА ЗМІЦНЕННЯ ДЕТАЛЕЙ ГІРНИЧИХ МАШИН

Мета та завдання. Дослідження та аналіз можливостей застосування

відновлювальних електродугових покриттів при ремонті машин і механізмів, які
застосовуються в різних галузях промисловості.
Методи дослідження. Дослідження пористості отриманих електродугових
покриттів здійснювали за допомогою комп'ютерної металографії. Твердість визначали
на приладі типу Віккерс. Вивчення теплофізичних властивостей покриттів проводили
за методом динамічного калориметра. Міцність зчеплення покриттів з основою
визначали методом "витягування штифта". Визначення зносостійкості проводили на
машині тертя СМЦ - 2 за схемою «ролик-колодка» в умовах обмеженої мастила.
Визначення областей когерентного розсіювання рентгенівського випромінювання для
оцінки розмірів субструктури матеріалу покриття здійснювали методом
рентгеноструктурного аналізу на установці ДРОН-3.
Основні результати. Отримав подальший розвиток електродуговий метод
нанесення покриттів за рахунок удосконалення конструкції розпилювальної головки, що

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Mining machines and energy GEOENGINEERING, iss. 7. 2022

дозволило підвищити коефіцієнт використання матеріалу при їх напиленні та фізико-

механічні, а також експлуатаційні властивості. Встановлено закономірності впливу
електроімпульсного впливу на мікроструктуру і фізико-механічні властивості
(твердість, щільність, міцність зчеплення, теплопровідність, зносостійкість)
електродугових покриттів. Отримав подальший розвиток процесу
передрекристалізаційної обробки напилених покриттів у напрямку термічної
стабілізації полігонізаційної субструктури за рахунок подальшої деформації отриманих
покриттів.
Висновки та практичне значення. Удосконалено електродуговий розпилювач, який
дозволяє поліпшити якість композиційних покриттів шляхом збільшення швидкості
частинок у високотемпературному гетерофазному струмені й зменшення кута її
розкриття, що призводить до підвищення Кім при напиленні з 0,63 до 0,74. При цьому
приріст твердості металевої матриці в композиційному електродуговому покритті
становить 21%, їх міцність зчеплення з основою збільшується на 26%, зносостійкість
в 6,9 раза в порівнянні з ненаповненим покриттям. Визначено оптимальні амплітудно-
частотні параметри електроімпульсного впливу при електродуговому напиленні дроту
Св-08Г2С (частота імпульсів – 6,5 кГц, амплітуда – 5 кВ), які забезпечують підвищення
твердості до 35 %, міцності зчеплення з основою до 30% і зносостійкості покриттів
1,7 раза за рахунок подрібнення і прискорення напилюваних частинок. Встановлено
оптимальні температуро-часові параметри передрекристалізаційної термічної
обробки, які забезпечують подальше підвищення твердості покриттів за рахунок
подрібнення субзерен до наномасштабного розміру включно. Показана можливість
термічної стабілізації полігонізаційної субструктури електродугових покриттів,
отриманих розпиленням дроту марки 12Х18Н10Т, шляхом їх додаткової пластичної
деформації.
Застосування результатів досліджень, отриманих в роботі, надають можливість
розширити номенклатуру дешевших напилюваних матеріалів для нанесення покриттів
з підвищеними фізико-механічними та експлуатаційними властивостями на важко
навантажені деталі машинобудування, електротехнічні вироби та деталі військово-
промислового комплексу.
Ключові слова: електродугові композиційні покриття, електроімпульсний вплив,
термічна обробка.

СПИСОК ВИКОРИСТАНОЇ ЛІТЕРАТУРИ

[1] Qi Xiao, Wen lei Sun, Kai xinYang et. al., ″Wear mechanisms and micro-evaluation on WC
particles investigation of WC-Fe composite coatings fabricated by laser cladding″, Surface and
Coating Technology, vol. 420, 2021.
https://doi.org/10.1016/j.surfcoat.2021.127341
[2] Vernon E. Buchanan, ″Solidification and microstructural characterisation of iron–chromium
based hardfaced coatings deposited by SMAW and electric arc spraying″, Surface and Coatings
Technology, vol. 203, issue 23, pp. 3638-3646, 2009.
https://doi.org/10.1016/j.surfcoat.2009.05.051
[3] E. Badisch, M. Kirchgaßner, ″Influence of welding parameters on microstructure and wear
behaviour of a typical NiCrBSi hardfacing alloy reinforced with tungsten carbide″, Surface and
Coatings Technology, vol. 202, issue 24, pp. 6016-6022, 2008.
https://doi.org/10.1016/j.surfcoat.2008.06.185
[4] D. A. Santana, G. Y. Koga, W. Wolf, I. A. Bataev, A. A. Ruktuev, C. Bolfarini, C. S. Kiminami,
W. J. Botta, A. M. Jorge Jr, ″Wear-resistant boride reinforced steel coatings produced by non-
vacuum electron beam cladding″, Surface and Coatings Technology, vol. 386, 2020.
https://doi.org/10.1016/j.surfcoat.2020.125466

72
Гірничі машини і енергетика ГЕОІНЖЕНЕРІЯ, вип. 7. 2022

[5] C. Schulz, T. Schläfer, E. Charrault, et al., ″Erosive Wear Testing of Laser Clad and HVOF
Coatings for Drilling in Mining″, Journal of Thermal Spray Technology, vol. 29, pp. 520–529,
2020. https://doi.org/10.1007/s11666-020-00985-z
[6] H. Zhu, H. Li, ″Microstructure Evolution of Thermally Sprayed TiB2-Ni Cermet Coating:
Comparison Between APS and HVOF Process″, Journal of Thermal Spray Technology, 28, 535–
543 (2019). https://doi.org/10.1007/s11666-018-0809-9
[7] Kai Chong, Yong Zou, Dongting Wu, Yingwen Tang, Yongang Zhang, ″Pulsed laser remelting
supersonic plasma sprayed Cr3C2-NiCr coatings for regulating microstructure, hardness and
corrosion properties″, Surface and Coatings Technology, vol. 418, 2021.
https://doi.org/10.1016/j.surfcoat.2021.127258
[8] V. Y. Ulianitsky, I. S. Batraev, D. K. Rybin, et al., ″Detonation Spraying of Cr3C2-NiCr Coatings
and Their Properties″, Journal of Thermal Spray Technology, vol. 31, pp. 598–608, 2022.
https://doi.org/10.1007/s11666-021-01301-z
[9] В. А. Роянов, В. И. Бобиков, ″Влияние пульсирующей распыляющей струи на структуру и
микротвердость частиц покрытий при электродуговой металлизации″, Вісник
Приазовського державного технічного університету, №20, с. 172–175, 2010.
[10] А. Ф. Илющенко, А. И. Шевцов, В. А. Оковитый, Г. Ф. Громыко, Процессы формирования
газотермических покрытий и их моделирование. Минск: Беларус. Навука, 2011.
[11] А. М. Кадырметов, ″Исследование процессов плазменного нанесения и упрочнения
покрытий и пути управления их качеством″, Научный журнал КубГАУ. №8. с. 1,– 8, 2012.
[12] О. М. Дубовий, А. А. Карпеченко, С. М. Шумов, ″Пристрій для електродугового
напилення″, 83603 Україна МПК С23С 4/00, № u 2007 07157, Лип.25, 2008.
[13] О. М. Дубовий, Т. А. Янковець, А. А. Карпеченко, О. О. Жданов, ″Спосіб нанесення
покриттів″, 88755 Україна МПК С23С 4/18, № a 2009 02658, Лист. 10, 2009.
[14] А. Н. Дубовой, А. А. Карпеченко, М. Н. Бобров, ″Повышение эксплуатационных свойств
электродуговых и плазменных покрытий электроимпульсным воздействием на
двухфазный высокотемпературный поток″, Автоматическая сварка, № 8 (734). с. 39-43.
2014. http://dspace.nbuv.gov.ua/handle/123456789/103490
[15] А. Н. Дубовой, А. А. Карпеченко, М. Н. Бобров, Ю. Е. Неделько, ″Формирование
наноразмерной полигонизационной в напыленных электродуговых покрытиях″,
Автоматическая сварка, № 3 (762), с. 40-43, 2017. https://doi.org/10.15407/as2017.03.05
[16] О. М. Дубовий, А. А. Карпеченко, М. М. Бобров, О. О. Жданов, Т. О. Макруха, Ю. Є.
Неделько, ″Формування нанорозмірної полігонізаційної субструктури та її вплив на
фізико-механічні властивості металів, стопів і напорошених покриттів″, Металлофизика и
новейшие технологии, т. 39, № 2, с. 209–243, 2017.
https://doi.org/10.15407/mfint.39.02.0209
[17] А. Н. Дубовой, А. А. Карпеченко, М. Н. Бобров, А. В. Лабарткава, ″Развитие технологии
газотермического напыления покрытий формированием измельчённой наноразмерной
полигонизационной субструктуры″, Металлофизика и новейшие технологии, т. 42, № 5, с.
631-653, 2020. https://doi.org/10.15407/mfint.42.05.0631
[18] А. Н. Дубовой, А. А. Карпеченко, М. Н. Бобров, А. В Лабарткава, ″Повышение физико-
механических и эксплуатационных свойств электродуговых и плазменных покрытий
формированием термически стабильной измельчённой и наноразмерной субструктуры″,
Металлофизика и новейшие технологии, т. 42, № 4, с. 461-480, 2019.
https://doi.org/10.15407/mfint.41.04.0461
[19] О. М. Дубовий, А. А. Карпеченко, М. М. Бобров, А. О. Мазуренко, ″Пристрій для
електродугового напилення композиційних покриттів″, 111760 Україна МПК C23C 4/131,
№ a 2014 07318, Черв.10, 2016.
[20] О. М. Дубовий, О. В. Чечель, М. М. Бобров, Ю. Є.Неделько, ″Перспективи підвищення
фізико-механічних властивостей газотермічних покриттів електроімпульсною дією″,
Науковий вісник національного гірничого університету, №1, с. 82-87, 2017.
http://nbuv.gov.ua/UJRN/Nvngu_2017_1_15

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