The method of TiSiCN-coatings deposition by anodic evaporation of Ti and decomposition of an organosilicon precursor (hexamethyldisilazane) in a low-pressure (∼1 mTorr) nitrogen-argon arc discharge with a self-heated hollow cathode is investigated. The plasma composition was analyzed by optical emission spectroscopy. TiSiCN coatings with a thickness of up to 10 microns and a hardness of up to 30 GPa were obtained in 1.5 hours at a temperature of 400 C. © Published under licence by IOP Publishing Ltd.The work was supported by the Russian Science Foundation (grant no. 20-79-10059)

Bruhanova, Y. A.

Menshakov, A. I.

Skorynina, P. A.

Journal of Physics Conference Series

Institutional repository of Ural Federal University named after the first President of Russia B.N.Yeltsin

Journal of Physics: Conference SeriesPAPER • OPEN ACCESSObtaining of TiSiCN coatings by anodicevaporation of titanium and decomposition ofhexamethyldisilazane in a low-pressure arcdischargeTo cite this article: A I Menshakov et al 2021 J. Phys.: Conf. Ser. 1954 012032 View the article online for updates and enhancements.You may also likeMulti-scale investigation in the frequencydomain of Ar/HMDSO dusty plasma withpulsed injection of HMDSOV Garofano, R Bérard, S Boivin et al.-Growth of fractal structures in flames withsilicon admixtureB. M. Smirnov, M. Dutka, V. M. van Essenet al.-Plasma-polymerized hexamethyldisilazanetreated by nitrogen plasma immersion ionimplantation techniqueR Y Honda, R P Mota, R G S Batocki et al.-This content was downloaded from IP address 212.193.94.28 on 14/04/2022 at 06:04Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distributionof this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Published under licence by IOP Publishing Ltd15th International Conference on Films and Coatings (ICFC 2021)Journal of Physics: Conference Series 1954 (2021) 012032IOP Publishingdoi:10.1088/1742-6596/1954/1/0120321Obtaining of TiSiCN coatings by anodic evaporation  of titanium and decomposition of hexamethyldisilazane  in a low-pressure arc discharge A I Menshakov1,2, Yu A Bruhanova1 and P A Skorynina3 1 Institute of Electrophysics of the Ural Branch of the Russian Academy of Sciences, 106 Amundsen St., Yekaterinburg, 620016, Russia 2 Ural Federal University, 19 Mira St., Yekaterinburg, 620002, Russia 3 Institute of Engineering Science UB RAS, 34 Komsomolskaya str., Yekaterinburg, 620049, Russia  E-mail: menshakovandrey@mail.ru  Abstract. The method of TiSiCN-coatings deposition by anodic evaporation of Ti and decomposition of an organosilicon precursor (hexamethyldisilazane) in a low-pressure (~1 mTorr) nitrogen-argon arc discharge with a self-heated hollow cathode is investigated. The plasma composition was analyzed by optical emission spectroscopy. TiSiCN coatings with a thickness of up to 10 microns and a hardness of up to 30 GPa were obtained in 1.5 hours at a temperature of 400oC. One of the promising hard protective wear-resistant coatings is TiSiCN-coatings that are nanocomposite (nc) and, depending on the content of various components, can have a structure consisting of an amorphous matrix of silicon nitride or silicon carbonitride with the inclusion of TiCN nanocrystals [1]. The key property of this nc structure is its high temperature resistance, which allows TiSiCN coatings to maintain high hardness (up to 55 GPa) up to 800°C [2], as well as oxidation resistance up to 900°C [3]. In addition, the presence of self-lubricating components in the form of amorphous or diamond-like carbon nanoparticles in the microstructure of such TiSiCN coatings can significantly reduce their coefficient of friction (FC) [4]. Due to the combination of low FC and high hardness, TiSiCN coatings can provide excellent wear resistance compared to conventional nitride or carbonitride coatings [5]. Among the modern and promising methods for producing TiSiCN coatings, the most effective are the methods of plasma-chemical gas phase deposition (PECVD) using multicomponent gas mixtures, including low-toxic organosilicon volatile compounds (OSC) [6]. However, the approaches currently used either do not meet the requirements for safety and environmental friendliness, as, for example, when using toxic and explosive gas components [7], or are quite complex [6] and do not allow independent and wide-ranging control of many conditions that affect the characteristics of the resulting coatings. In this paper, a method of deposition of TiSiCN coatings by reactive anodic evaporation of titanium in an arc with a self-heated hollow cathode in vapors of an organosilicon precursor (hexamethyldisilazane) is investigated. The advantages of this method are the possibility of independent changes in the pressure and composition of the gas mixture, the density of the ion current and the degree of ion exposure to the treated surface. 15th International Conference on Films and Coatings (ICFC 2021)Journal of Physics: Conference Series 1954 (2021) 012032IOP Publishingdoi:10.1088/1742-6596/1954/1/0120322The experiments were carried out in a gas-discharge system, the scheme of which is shown in figure 1, and the design is described in detail in [8]. The main difference between the system under consideration and [8] is the presence of a second anode-a crucible connected in parallel to the main anode. The crucible was a cylinder with a diameter and height of 13 mm, made of graphite MPG-7, in which pieces of titanium were placed. Hexamethyldisilazane (HMDS, [(CH3)3Si]2NH), the advantages of which are the presence in the composition of all the necessary elements and connections between them, its high volatility, as well as availability and low cost and low toxicity. In addition, it was shown in [9] that in the HMDS medium it is possible to obtain TiSiCN coatings with a much lower coefficient of friction than when using tetramethylsilane. The HMDS vapor source was located opposite the sample holder at a distance of 12 cm.                                    Figure 1. Electrode scheme of the gas-discharge system. At the initial stage, Ar was injected into the cathode cavity and a discharge between the cathode and the anode was ignited. The Id current in the cathode circuit was regulated in the range of 0-50 A, while the discharge voltage was 60-200 V. Then a voltage was applied to the crucible, and the Icr current in the crucible circuit was regulated in the range of 0-10 A. Due to the small size of the crucible, a sufficiently high power density of the electronic current on it was achieved, which provided heating of the crucible up to 2100oC. N2 was introduced into the chamber through the cathode cavity only after heating the crucible above the melting point of titanium, since in the solid state on the surface of Ti in a nitrogen medium at high temperatures, an intensive formation of TiN occurs, which has a significantly lower saturated vapor pressure and prevents the ingress of titanium vapors into the processing zone. An insulated table with AISI430 stainless steel samples was placed opposite the crucible at a distance of 8 cm from it. The voltage on the table was -100 V relative to the anode. Measurements of the ion saturation current density ji on a flat one-sided probe with an area of 1 cm2 in the sample location area showed that in the absence of current in the crucible circuit, an increase in the discharge current to Id=50 A led to an increase in the ion current density to 10 mA/cm2. When the crucible was switched on with a current in its circuit Icr=5 A, the same value of the ion current density was achieved at half the total current Id=25 A. If we judge the proportion of titanium 15th International Conference on Films and Coatings (ICFC 2021)Journal of Physics: Conference Series 1954 (2021) 012032IOP Publishingdoi:10.1088/1742-6596/1954/1/0120323ions on the surface of the samples by the increment of the ion current during metal evaporation, then at a fixed cooled anode current in the Ar+N2 mixture, the increase in the crucible current Icr from 0 to 10 A allows us to increase the proportion of the current of metal ions on the samples to ~60-70 %. The density of the ion current reaches ~ 20 mA/cm2. The composition of plasma in a mixture of argon and nitrogen with titanium in the deposition region of coatings was studied by optical emission spectroscopy using the HR2000 spectrometer (OceanOptics, 200-1100 nm, resolution 0.8 nm). In all discharge modes, the spectra show lines of plasma-forming gases (Ar*, Ar+, N2*, N2+) and lines of excited atoms (Ti*-399.9, 453.3, 498.2, 504 nm) and titanium ions (Ti+-337.3, 364.3, 374.2 nm) (figure 2). The intensity of Ti lines in the spectra is higher than the intensity of Ar lines, which indicates a high concentration and degree of activation of metal vapors. In addition, a strong line of the H* 656.3 nm atom belonging to the Balmer series is detected in the plasma spectrum, and its intensity increases with the discharge current, which indicates an increase in the degree of decomposition of HMDS. The test coatings were obtained at a discharge current of 20 A and a current in the crucible circuit of 2 A. Before deposition, the surface of the samples was cleaned with Ar+ ions with an energy of 500 eV at a current density of 5 mA/cm2 for 5 minutes. During deposition process the potential of the samples was reduced to ~(-100) V relative to the anode. To ensure good adhesion between the coating and the base material, a Ti sublayer with a thickness of ~200 nm was deposited, after which N2 and hexamethyldisilazane were fed into the chamber. The thickness of the coatings measured by the ball abrasion method on the Calotest device for a 1.5-hour cycle was ~10 µm (figure 3), and their microhardness, measured using a dynamic Shimadzu DUH-211s microhardness meter at a load of 10 mN, was ~28-30 GPa, which is significantly higher than the microhardness of TiN coatings (~20-22 GPa) obtained by the same method, but without the addition of HMDS.    Figure 2. Optical emission spectrum of the discharge plasma.  Figure 3. The cross section of the sample with a TiSiCN coating. The study of the microchemical composition of the coatings, performed using a Tescan VEGA II XMU scanning electron microscope with an INCA ENERGY 450 X-ray energy dispersive microanalysis system, showed that the coating contains Ti (30 at.%), Si (37 at.%), N (17 at.%), C (13 at.%), O (3 at.%). This ratio of elements in the coating is not optimal from the point of view of obtaining the maximum mechanical characteristics, the optimization of the coating composition will be the subject of further research. Thus, it is shown that the use of an arc discharge with a self-heated hollow cathode simultaneously to generate a dense plasma, heat a refractory crucible, and decompose the vapors of an organosilicon 15th International Conference on Films and Coatings (ICFC 2021)Journal of Physics: Conference Series 1954 (2021) 012032IOP Publishingdoi:10.1088/1742-6596/1954/1/0120324precursor makes it possible to activate both metal vapors and precursor vapors, while also providing a high (up to 20 mA/cm2) ion current density on the surface of samples. The coatings obtained by this method have good adhesion and a homogeneous dense structure. At the same time, the rate of coating formation reaches 6-7 µm/h, and their hardness at a deposition temperature of 400°C is 30 GPa. Acknowledgements The work was supported by the Russian Science Foundation (grant no. 20-79-10059). References [1]  Xu Y X, Chen L, Liu Z Q, Pei F and Du Y 2017 Surf. Coat. Technol. 321 180–5 [2]  Dayan M, Shengli M and Xu K 2005 Surf. Coat. Technol. 200 382–6 [3]  Endler I, Höhn M, Schmidt J et al. 2013 Surf. Coat. Technol. 215 133–40 [4]  Ma S, Ma D, Guo Y et al. 2007 Acta Mater. 55 6350–5 [5]  Xu H, Nie X and Wei R 2006 Surf. Coat. Technol. 201 4236–41 [6]  Abedi M, Abdollah-zadeh A, Bestetti M et al. 2018 Appl. Surf. Sci. 444 377–86 [7]  Kuo D H and Huang K W 2001 Thin Solid Films 394 72–80 [8]  Menshakov A I, Emlin D R, Surkov Yu S and Cholakh S O 2018 J. of Phys.: Conf. Ser. 1134 012039 

Obtaining of TiSiCN Coatings by Anodic Evaporation of Titanium and Decomposition of Hexamethyldisilazane in a Low-Pressure Arc Discharge

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Obtaining of TiSiCN Coatings by Anodic Evaporation of Titanium and Decomposition of Hexamethyldisilazane in a Low-Pressure Arc Discharge

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