The complex of properties including the structure, adhesive strength, internal stresses, tribological properties, microhardness and crack-resistance of nanoscale carbon coatings obtained by the pulsed vacuum-arc method on single-crystal silicon substrates was investigated. Two types of samples of the carbon coating: type (i) formed at the normal location of the substrate relative to the geometric axis of the plasma flow (θ = 0°); type (ii) obtained at an angle θ = 70° were studied. The analysis of the experimental results showed, that the angle of plasma flow incidence relative to the substrate drastically affects the properties of carbon coatings. The structure, adhesion, internal stresses, wear resistance, crack resistance are interrelated and determined by the radiation-diffusion sealing during the process of carbon coating deposition from the carbon plasma flow. Nanoscale carbon coatings can significantly improve the strength and tribological properties of different tools, parts and products.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3530

Galkina, M.E.

Gerus, J.V.

Kolpakov, A.Y.

Kovaleva, M.G.

Poplavsky, A.I.

Sudzhanskaya, I.V.

SocioEconomic Challenges Journal (Sumy State University)

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE  
NANOMATERIALS: APPLICATIONS AND PROPERTIES 
Vol. 2 No 2, 02FNC05(2pp) (2013) 
 
 
2304-1862/2013/2(2)02FNC05(2) 02FNC05-1  2013 Sumy State University 
Properties of Nanoscale Carbon Coatings Obtained by the Pulsed Vacuum-Arc Method on 
Silicon 
 
A.Ya. Kolpakov*, A.I. Poplavsky†, M.E. Galkina, M.G. Kovaleva, I.V. Sudzhanskaya, J.V. Gerus 
 
Belgorod State National Research University, 85, Pobedy Str., 308015 Belgorod, Russian Federation 
 
(Received 08 May 2013; published online 30 August 2013) 
 
The complex of properties including the structure, adhesive strength, internal stresses, tribological 
properties, microhardness and crack-resistance of nanoscale carbon coatings obtained by the pulsed 
vacuum-arc method on single-crystal silicon substrates was investigated. Two types of samples of the 
carbon coating: type (i) formed at the normal location of the substrate relative to the geometric axis of the 
plasma flow (θ  0°); type (ii) obtained at an angle θ  70° were studied. The analysis of the experimental 
results showed, that the angle of plasma flow incidence relative to the substrate drastically affects the 
properties of carbon coatings. The structure, adhesion, internal stresses, wear resistance, crack resistance 
are interrelated and determined by the radiation-diffusion sealing during the process of carbon coating 
deposition from the carbon plasma flow. Nanoscale carbon coatings can significantly improve the strength 
and tribological properties of different tools, parts and products. 
 
Keywords: Nanoscale carbon coating, Pulsed vacuum-arc method, Properties. 
 
 PACS numbers: 68.60. – p 
 
 
                                                        
* kolpakov@bsu.edu.ru 
† poplavsky@bsu.edu.ru 
1. INTRODUCTION 
 
Applications of amorphous carbon coatings are de-
fined by their high microhardness, low friction coeffi-
cient, chemical inertness, transparency in the infrared 
radiation range, bioinertia, unique emission character-
istics, etc. Currently, many researchers are interested 
in carbon coatings with thickness less than 100 nm  
[1-3], that are promising for applications in various 
fields of science and technology. Thus, we have devel-
oped technology for deposition of nanoscale carbon 
coatings doped with nitrogen [2] that has been success-
fully used to improve the operational characteristics of 
scanning probe microscopes microprobe manufactured 
by NT-MDT. One of the most promising deposition 
methods of nanoscale coatings is a pulsed vacuum arc 
method, which allows obtaining coatings with required 
thickness by giving a certain number of pulses, dosing 
of the thermal load on the substrate by changing the 
pulse repetition rate, and, in addition, does not require 
the applying of the accelerating potential to the sub-
strate. 
 
2. EXPERIMENTAL RESULTS 
 
The complex of properties including the structure, 
adhesive strength, internal stress, tribological proper-
ties, microhardness and crack-resistance of nanoscale 
carbon coatings obtained by the pulsed vacuum-arc 
method on single-crystal silicon substrates KEF-4.5 
with the orientation (100) was investigated. Two types 
of samples of the carbon coating: type (i) formed at the 
normal location of the substrate relative to the geomet-
ric axis of the plasma flow (θ  0°); type (ii) obtained at 
an angle θ  70° were studied. 
The properties of carbon coatings are defined by the 
content in the amorphous carbon matrix of atomic 
bonds formed by sp2 and sp3- hybridization of electron 
orbitals. Structural studies of nanoscale carbon coat-
ings by electron energy loss spectroscopy by using a 
transmission electron microscope Tecnai G2 F20  
S-TWIN showed that the content of the atomic bonds 
with sp2 - hybridization in coatings (ii) is higher than in 
coatings (i) [4].  
The adhesive / cohesive strength of the carbon coat-
ings with thickness 100 nm on silicon substrate with 
using tester REVETEST of CSM Instruments company 
was investigated. Diamond spherical "Rockwell C" 
indenter was used for making scratches at continuous-
ly increasing load for registration of acoustic emission 
and friction coefficient. The adhesive strength criterion 
was the critical load, leading to the complete destruc-
tion of the coating up to the substrate material. The 
value of the adhesive strength was determined visually 
using an optical microscope, as well as the coefficient 
friction and acoustic emission variation curves. Adhe-
sive strength of the coatings (i) was 7 H, and coatings 
(ii) – 12 N. 
The significant difference in the adhesion strength 
of coatings (i) and (ii) can be explained by the experi-
mental results of the value of internal stresses remai-
ning after the deposition of the carbon coating on the 
cold substrate from the low-temperature carbon plasma 
flow. Value of the internal compressive stresses in the 
coatings (i) was 10 GPa, and in coatings (ii) – 4 GPa. 
Hence, the anomalously high values of the internal 
compressive stresses tending to tear the coating from 
the substrate cause the lower adhesion strength of 
coatings (i). 
Explanation of the effect of the plasma flow angle 
relative to the substrate on the formation of the struc-
ture, appearance and partial relaxation of the internal 
stresses [4] based on the concepts of radiation-diffusion 
sealing is proposed. The decrease of the internal stress 
approximately 2 times with increasing angle θ from 0° 
 A.YA. KOLPAKOV, A.I. POPLAVSKY, M.E. GALKINA, ET AL. PROC. NAP 2, 02FNC05 (2013) 
 
 
02FNC05-2 
to 70° is due to the smaller depth of radiation-induced 
defects in the case of the plasma flow tilted relative to 
the surface of substrate on which the coating is formed. 
This leads to greater likelihood of internal stress relax-
ation a result of defect migration to sinks (the coating 
surface), due to the decrease of the ion effect seal. The 
increase of sp2- phase content in the carbon matrix is 
caused by the reduction of the ion sealing effect. 
The complex tribological study of the initial silicon 
substrate and the coating samples by the standard 
wear test scheme "ball-disc" (ASTM G99-959 and 
DIN 50324) using an automated friction machine 
(Tribometer, of CSM Instruments) and an analysis of 
the coatings friction track and the wear scar on the 
counter body (sapphire ball diameter of 6 mm) were 
performed. The wear traces of the coatings on Si sam-
ples and the wear scar on the balls were studied after 
the tests using an inverted optical microscope Olym-
pus GX 51. Measurement of the average cross-
sectional area and the depth of the friction track were 
performed in 4 opposite regions of samples using au-
tomated precision contact profilometer Surtronic 25. 
It was found that nanosized carbon coating has a low 
friction coefficient ( 0.1), high wears resistance, and 
is the ideal protection of the silicon product from 
premature wear in friction. Wear factor 
(mm3 / (N × m)) for the coating (i) is significantly low-
er than for the coating (ii). 
The micro-hardness and fracture toughness of the 
initial silicon and the "coating-substrate" system on a 
DM-8 microhardness gage, equipped with a Vickers 
pyramid, at loads of 10, 25 and 50 g were investigated. 
For the crack-resistance criterion the average length of 
cracks formed during the microindentation and deter-
mined for each load from a series of prints was adopted                                                            
At a 10 g load the micro-hardness of "coating-
substrate" system was 1750 HV, microhardness of the 
initial silicon – 1010 HV. It was revealed that na-
nosized carbon coating significantly improves the 
strength properties of silicon. Crack resistance of the 
"coating-substrate" system is significantly higher com-
pared with the initial silicon substrate. Minimum va-
lues of the average cracks length correspond to the 
coating type (i). Thus, the more stress state of the coat-
ing corresponds to a smaller length of cracks. This fact 
is consistent with our previous studies of internal 
stress and crack-resistance of carbon coatings doped by 
different elements [3]. 
 
3. CONCLUSION 
 
Analysis of the study results leads to the following 
conclusions: 
• Angle of the plasma flow incidence to the substrate 
influences dramatically on the properties of the carbon 
coatings. 
• Structure, adhesive strength, internal stress, wear- 
and crack-resistance are interconnected and determined 
by the radiation-diffusion sealing in the process of coat-
ing deposition from the carbon plasma flow. 
• The nano-sized carbon coatings deposited by pulsed 
vacuum-arc method allow significantly increase the 
strength and tribological properties of various tools, 
parts and products. 
 
AKNOWLEDGEMENTS 
 
The work was performed within the framework of 
the state task of the Ministry of Education and Science 
of the Russian Federation  by the subordinate universi-
ties on perform research and developments, project 
No 2.3451.2011 «Influence of the heat treatment on the 
structure and properties of diamond-like carbon coat-
ings». 
 
 
REFERENCES 
 
1. A.C. Ferrari, Surf. Coat. Tech. 180-181, 190 (2004). 
2. M.E. Galkina, A.Ya. Kolpakov, O.V. Safronova, 
I.V. Sudzhanskaya, Patent RU no 2342468 (2008). 
3. A.Ya. Kolpakov, A.I. Poplavsky, M.E. Galkina, 
I.V. Sudzhanskaya, I.Yu. Goncharov, O.A. Druchinina, 
N.V. Strigunov, V.A. Kharchenko, O.Yu. Merchansky, 
Nanotechnologies in Russia 5, 160 (2010).  
4. A.Ya. Kolpakov, A.I. Poplavsky, M.E. Galkina, 
I.V. Sudzhanskaya, O.Yu. Merchansky, Uprochnyayush-
chie Technologii i Pokrytiya, 4, 40 (2012). 
 


Properties of Nanoscale Carbon Coatings Obtained by the Pulsed Vacuum-Arc Method on Silicon

Electronic Sumy State University Institutional Repository

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE  NANOMATERIALS: APPLICATIONS AND PROPERTIES Vol. 2 No 2, 02FNC05(2pp) (2013)   2304-1862/2013/2(2)02FNC05(2) 02FNC05-1  2013 Sumy State University Properties of Nanoscale Carbon Coatings Obtained by the Pulsed Vacuum-Arc Method on Silicon  A.Ya. Kolpakov*, A.I. Poplavsky†, M.E. Galkina, M.G. Kovaleva, I.V. Sudzhanskaya, J.V. Gerus  Belgorod State National Research University, 85, Pobedy Str., 308015 Belgorod, Russian Federation  (Received 08 May 2013; published online 30 August 2013)  The complex of properties including the structure, adhesive strength, internal stresses, tribological properties, microhardness and crack-resistance of nanoscale carbon coatings obtained by the pulsed vacuum-arc method on single-crystal silicon substrates was investigated. Two types of samples of the carbon coating: type (i) formed at the normal location of the substrate relative to the geometric axis of the plasma flow (θ  0°); type (ii) obtained at an angle θ  70° were studied. The analysis of the experimental results showed, that the angle of plasma flow incidence relative to the substrate drastically affects the properties of carbon coatings. The structure, adhesion, internal stresses, wear resistance, crack resistance are interrelated and determined by the radiation-diffusion sealing during the process of carbon coating deposition from the carbon plasma flow. Nanoscale carbon coatings can significantly improve the strength and tribological properties of different tools, parts and products.  Keywords: Nanoscale carbon coating, Pulsed vacuum-arc method, Properties.   PACS numbers: 68.60. – p                                                           * kolpakov@bsu.edu.ru † poplavsky@bsu.edu.ru 1. INTRODUCTION  Applications of amorphous carbon coatings are de-fined by their high microhardness, low friction coeffi-cient, chemical inertness, transparency in the infrared radiation range, bioinertia, unique emission character-istics, etc. Currently, many researchers are interested in carbon coatings with thickness less than 100 nm  [1-3], that are promising for applications in various fields of science and technology. Thus, we have devel-oped technology for deposition of nanoscale carbon coatings doped with nitrogen [2] that has been success-fully used to improve the operational characteristics of scanning probe microscopes microprobe manufactured by NT-MDT. One of the most promising deposition methods of nanoscale coatings is a pulsed vacuum arc method, which allows obtaining coatings with required thickness by giving a certain number of pulses, dosing of the thermal load on the substrate by changing the pulse repetition rate, and, in addition, does not require the applying of the accelerating potential to the sub-strate.  2. EXPERIMENTAL RESULTS  The complex of properties including the structure, adhesive strength, internal stress, tribological proper-ties, microhardness and crack-resistance of nanoscale carbon coatings obtained by the pulsed vacuum-arc method on single-crystal silicon substrates KEF-4.5 with the orientation (100) was investigated. Two types of samples of the carbon coating: type (i) formed at the normal location of the substrate relative to the geomet-ric axis of the plasma flow (θ  0°); type (ii) obtained at an angle θ  70° were studied. The properties of carbon coatings are defined by the content in the amorphous carbon matrix of atomic bonds formed by sp2 and sp3- hybridization of electron orbitals. Structural studies of nanoscale carbon coat-ings by electron energy loss spectroscopy by using a transmission electron microscope Tecnai G2 F20  S-TWIN showed that the content of the atomic bonds with sp2 - hybridization in coatings (ii) is higher than in coatings (i) [4].  The adhesive / cohesive strength of the carbon coat-ings with thickness 100 nm on silicon substrate with using tester REVETEST of CSM Instruments company was investigated. Diamond spherical "Rockwell C" indenter was used for making scratches at continuous-ly increasing load for registration of acoustic emission and friction coefficient. The adhesive strength criterion was the critical load, leading to the complete destruc-tion of the coating up to the substrate material. The value of the adhesive strength was determined visually using an optical microscope, as well as the coefficient friction and acoustic emission variation curves. Adhe-sive strength of the coatings (i) was 7 H, and coatings (ii) – 12 N. The significant difference in the adhesion strength of coatings (i) and (ii) can be explained by the experi-mental results of the value of internal stresses remai-ning after the deposition of the carbon coating on the cold substrate from the low-temperature carbon plasma flow. Value of the internal compressive stresses in the coatings (i) was 10 GPa, and in coatings (ii) – 4 GPa. Hence, the anomalously high values of the internal compressive stresses tending to tear the coating from the substrate cause the lower adhesion strength of coatings (i). Explanation of the effect of the plasma flow angle relative to the substrate on the formation of the struc-ture, appearance and partial relaxation of the internal stresses [4] based on the concepts of radiation-diffusion sealing is proposed. The decrease of the internal stress approximately 2 times with increasing angle θ from 0°  A.YA. KOLPAKOV, A.I. POPLAVSKY, M.E. GALKINA, ET AL. PROC. NAP 2, 02FNC05 (2013)   02FNC05-2 to 70° is due to the smaller depth of radiation-induced defects in the case of the plasma flow tilted relative to the surface of substrate on which the coating is formed. This leads to greater likelihood of internal stress relax-ation a result of defect migration to sinks (the coating surface), due to the decrease of the ion effect seal. The increase of sp2- phase content in the carbon matrix is caused by the reduction of the ion sealing effect. The complex tribological study of the initial silicon substrate and the coating samples by the standard wear test scheme "ball-disc" (ASTM G99-959 and DIN 50324) using an automated friction machine (Tribometer, of CSM Instruments) and an analysis of the coatings friction track and the wear scar on the counter body (sapphire ball diameter of 6 mm) were performed. The wear traces of the coatings on Si sam-ples and the wear scar on the balls were studied after the tests using an inverted optical microscope Olym-pus GX 51. Measurement of the average cross-sectional area and the depth of the friction track were performed in 4 opposite regions of samples using au-tomated precision contact profilometer Surtronic 25. It was found that nanosized carbon coating has a low friction coefficient ( 0.1), high wears resistance, and is the ideal protection of the silicon product from premature wear in friction. Wear factor (mm3 / (N × m)) for the coating (i) is significantly low-er than for the coating (ii). The micro-hardness and fracture toughness of the initial silicon and the "coating-substrate" system on a DM-8 microhardness gage, equipped with a Vickers pyramid, at loads of 10, 25 and 50 g were investigated. For the crack-resistance criterion the average length of cracks formed during the microindentation and deter-mined for each load from a series of prints was adopted                                                            At a 10 g load the micro-hardness of "coating-substrate" system was 1750 HV, microhardness of the initial silicon – 1010 HV. It was revealed that na-nosized carbon coating significantly improves the strength properties of silicon. Crack resistance of the "coating-substrate" system is significantly higher com-pared with the initial silicon substrate. Minimum va-lues of the average cracks length correspond to the coating type (i). Thus, the more stress state of the coat-ing corresponds to a smaller length of cracks. This fact is consistent with our previous studies of internal stress and crack-resistance of carbon coatings doped by different elements [3].  3. CONCLUSION  Analysis of the study results leads to the following conclusions: • Angle of the plasma flow incidence to the substrate influences dramatically on the properties of the carbon coatings. • Structure, adhesive strength, internal stress, wear- and crack-resistance are interconnected and determined by the radiation-diffusion sealing in the process of coat-ing deposition from the carbon plasma flow. • The nano-sized carbon coatings deposited by pulsed vacuum-arc method allow significantly increase the strength and tribological properties of various tools, parts and products.  AKNOWLEDGEMENTS  The work was performed within the framework of the state task of the Ministry of Education and Science of the Russian Federation  by the subordinate universi-ties on perform research and developments, project No 2.3451.2011 «Influence of the heat treatment on the structure and properties of diamond-like carbon coat-ings».   REFERENCES  1. A.C. Ferrari, Surf. Coat. Tech. 180-181, 190 (2004). 2. M.E. Galkina, A.Ya. Kolpakov, O.V. Safronova, I.V. Sudzhanskaya, Patent RU no 2342468 (2008). 3. A.Ya. Kolpakov, A.I. Poplavsky, M.E. Galkina, I.V. Sudzhanskaya, I.Yu. Goncharov, O.A. Druchinina, N.V. Strigunov, V.A. Kharchenko, O.Yu. Merchansky, Nanotechnologies in Russia 5, 160 (2010).  4. A.Ya. Kolpakov, A.I. Poplavsky, M.E. Galkina, I.V. Sudzhanskaya, O.Yu. Merchansky, Uprochnyayush-chie Technologii i Pokrytiya, 4, 40 (2012).  

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Properties of Nanoscale Carbon Coatings Obtained by the Pulsed Vacuum-Arc Method on Silicon

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