Thermophysics and Aeromechanics, 2014, Vol. 21, No. 5
The structure and physical-mechanical properties of the heat-resistant Ni-Co-Cr-Al-Y intermetallic coating obtained using rebuilt plasma equipment Yu.P. Tarasenko1, I.N. Tsareva1, O.B. Berdnik1, Ya.A. Fel 1, V.I. Kuzmin2, A.A. Mikhalchenko 2, and E.V. Kartaev2 1
Institute of Machine-Building Problems RAS, Nizhni Novgorod, Russia
2
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
E-mail:
[email protected],
[email protected] (Received July 9, 2013; in revised form March 4, 2014) Results of a study of the structure, physico-mechanical properties, and the resistance to heat of Ni-Co-Cr-Al-Y intermetallic coatings obtained by powder spraying on the standard UPU-3D plasma spray facility (plasmatron with self-establishing arc length) and on the rebuilt facility equipped with the enhanced-power PNK-50 plasmatron with 3 sectionalized inter-electrode insert, are reported. Coatings of higher density (ρ = 7.9 g/cm ) and higher microhardness 2 (Нμ = 770 kg-force/mm ) with lower porosity values (P = 5.7 %, Pc = 5.1 %, and P0 = 0.6 %) and high resistance to heat ((M − М0)/М0 = 1.2) were obtained. The developed coating is intended for protection of the working surfaces of turbine engine blades in gas-turbine power plants. Key words: plasma spraying, plasmatron, powder mixture, intermetallic phases, lamellar microstructure, porosity, microhardness, adhesion strength, high-temperature oxidation, resistance to heat, protection against hightemperature gas corrosion, turbine blades, gas-turbine power plants.
Introduction Enhancement of the reliability and in-service life of critical machine parts achieved via novel technological solutions is a priority tendency in current technology. Plasma spraying of heat-resistant coatings is one of the methods to solve the problem of protecting turbine blades in gas-turbine engines against the detrimental action of high-temperature working gases with temperatures ~ 900 °C, this problem being a critically important one in power machine building. Service properties of protecting coatings are defined by their phase composition, microstructure, thickness, density, adhesion strength, and the resistance to heat. This set of characteristics is defined by the conditions of the plasma spray process, being in turn characterized by such parameters as the arc voltage, the arc current, and the flow rates of the plasma-forming and carrier gases. The plasma spray process is based on using the thermal and kinetic energies of the plasma jet produced by a plasmatron [1]. The powder material is introduced into the jet. In the jet, the material undergoes heating, melting, and acceleration. As the material impinges onto © Yu.P. Tarasenko, I.N. Tsareva, O.B. Berdnik, Ya.A. Fel, V.I. Kuzmin, A.A. Mikhalchenko , and E.V. Kartaev, 2014
641
Yu.P. Tarasenko, I.N. Tsareva, O.B. Berdnik, Ya.A. Fel, V.I. Kuzmin, A.A. Mikhalchenko , and E.V. Kartaev
the target surface, it forms a coating. However, operational practice reveals insufficiently high resistance of protective coatings obtained on the standard plasma equipment [1]. In the present study, both the conventional plasma spraying technique implemented on the 30-kW UPU-3D plasma spray facility equipped with a plasmatron with self-establishing arc length [2, 3] and a modified technique implemented with an improved linear model PNK-50 plasmatron with sectioned inter-electrode insert and enhanced power characteristics (plasmatron power ~ 50 kW, plasma-jet mass-average temperature 6000 K, and average velocity of the particles at the nozzle outlet cross section 2400 m/s) were used for spraying coatings. 1. Experimental technique The objects under study were: − PNKh20С20Yu13-1 powder mixture of dispersiveness 40/80 μm; − samples of heat-resistant EI-893 nickel alloy coated with a heat-resistant Ni-Co-Cr-Al-Y coating plasma-sprayed from the PNKh20С20Yu13-1 powder mixture by the standard technique implemented on the UPU-3D facility; − samples of heat-resistant EI-893 nickel alloy with a heat-resistant Ni-Co-Cr-Al-Y coating plasma-sprayed from the same powder mixture on rebuilt equipment using the enhancedpower PNK-50 plasmatron. The heat-resistant coatings were obtained, first, by a plasma spray technique realized on the standard UPU-3D facility (process parameters: arc current is 450 A, working voltage is 70 V, flow rate of plasma-forming gas (argon) is 0.9 g/s, flow rate of carrier gas (argon) is 0.15 g/s, plasmatron outlet stand-off distance is 80 mm) and, second, by a plasma spray technique realized on the rebuilt facility equipped with the PNK-50 plasmatron (process parameters: arc current is 180 A, working voltage is 260 V, flow rate of plasma-forming gas (air) is 3.5 g/s, flow rate of carrier gas (air) is 0.27 g/s, plasmatron stand-off distance is 150 mm). The derivatographic study of the PNKh20K20Yu13-1 powder mixture was performed using a NEЕZSCH SЕA instrument (model 449F1). The phase compositions of the powder mixture and sprayed coatings were examined by the x-ray diffraction method on a Dron-3M diffractometer using Cu-Kα-radiation in Bragg—Brentano geometry. The metallographic study was performed using a NEOFOT-32 optical microscope and a VEGA//TESCAN scanning electron microscope. The density and porosity of examined coatings were determined using the hydrostatic weighting procedure described in State Standard (GOST) 18898-89 and a VIBRA analytical balance. The microhardness measurements were performed on metallographic sections by the GOST 9450-76 procedure on a PMT-3 microhardness-meter at 1-N loads applied to the indenter. The adhesion strength of sprayed coating at the substrate-coating interface was determined using the micro-indentation method implemented at 2-N load. Heat-resistance tests were performed on samples of coating-free heat-resistant nickel alloy and on similar samples covered by the heat-resistant Ni-Co-Cr-Al-Y intermetallic coating using the testing procedure developed at the Zhukovskii Air-Force Engineering Academy. Samples were preliminarily kept in salt solution (84 % sea salt + 16 % Na2SO4) during 24 hours, and then they were given annealing at temperature 850 °С during 500 hours in a furnace in air ambient. The resistance to heat was evaluated in terms of the relative change of sample mass in weighting tests performed on the VIBRA analytical balance following 50-hour intervals. The change of sample mass was calculated by the formula ΔМ = (M − М0) /М0.
(1)
Here, М0 is the mass of the sample prior to the annealing, and М is the mass of the sample in the course of tests. Using the data obtained in tests, curves of relative mass change versus test duration ΔМ (t) were plotted. Each of such curves was obtained by averaging the data obtained for three samples used in each test series. 642
Thermophysics and Aeromechanics, 2014, Vol. 21, No. 5
2. Investigation results 2.1. Equipment for plasma spraying of heat-resistant coatings The PNK-50 plasmatron gas-discharge chamber was a channel diverging from cathode to anode, made up by inter-electrode insert (IEI) sections electrically insulated from one another and from the electrodes. The inter-electrode insert not only defined the arc discharge length in the plasmatron channel; it also enabled the variation of this length and, hence, the variation of the operating voltage being achieved via variation of the total number of IEI sections. The plasmatron electrodes were the thermochemical cathode (copper cartridge with press-fit hafnium insert 2.5 mm in diameter) and the cylindrical copper anode. All the heatstressed plasmatron units were cooled with flowing water. As the plasma-forming, shielding, and carrier gases, either any technically pure gas or atmospheric air could be used. The plasma-forming gas was supplied into the plasmatron channel tangentially from the cathode side with the help of a vortex ring. The shielding gas was supplied into the gap in between the last section of the IEI and the anode also tangentially through the vortex ring. The plasmatron was designed for operation both in turbulent and laminar regimes (Fig. 1), which allowed maximization of the discharge velocity of plasma jet outflow in spraying metal powders and maximization of the time of residence of powder particles in the plasma flow during ceramic powders spraying. The plasmatron was assembled with a unit for powder annular injection into the plasma jet with gas-dynamic focusing [4]; that provided the passage of the whole mass of powder material through the high-temperature, high-velocity axial region of the plasma jet. As a result of the thermal and gas-dynamic intensification of the plasma spray process, a focused plasma jet with stable and high thermal and kinetic energies formed. The heating of sprayed particles to a temperature above the melting point enhances the strength of their adhesion to the substrate, while an increased velocity promotes the densification of deposited layers. Regulating the arc current, the flow rate and the composition of the plasma-forming and shielding gases, one can vary the power, temperature, and velocity of the plasma jet. C. Baundry et al. [5] modeled the behavior of a channeled electric arc typical of plasmatrons with self-establishing arc length (similar to the plasmatron used in the UPU-3D facility). It was shown that the fluctuations of arc length in the anode channel that occurred as a result of large- and small-scale arc shunting [6] make large contributions to the plasma-jet velocity and temperature fluctuations at the nozzle outlet (respectively up to 50 % and 20 %). To examine the effect of the voltage fluctuations due to the large- and small-scale arc shunting on the scatter of the parameters of Al2O3 and zirconium dioxide particles stabilized with yttrium oxide (YSZ) (velocity, temperature, and trajectory), J.F. Bisson et al. [7] used a plasmatron with vortex arc stabilization. In the present study, it was found that the occurrence of a large- and small-scale arc shunting process caused the formation of strong (in excess of 20 % of the total power) fluctuations in the frequency interval 5 to 20 kHz; those fluctuations exerted a determining influence on the above-indicated parameters of the powder particles. The presence of strong harmonics in this spectral region could be attributed to a high value of the ratio between the typical magnitude of arc-length fluctuations and the average arc length (1−3 calibers), this value being typical of this plasmatron type (one caliber is equal to
Fig. 1. Discharge regimes of plasma jets. Laminar jet (а) and turbulent jet (b).
643
Yu.P. Tarasenko, I.N. Tsareva, O.B. Berdnik, Ya.A. Fel, V.I. Kuzmin, A.A. Mikhalchenko , and E.V. Kartaev
the plasmatron channel diameter). In plasmatrons of the PNK-50 type with the fixed arc length defined by the inter-electrode insert, the fluctuations caused by the arc displacements over anode along the channel length are small in magnitude, that feature being typical of all operating regimes of the plasmatron. With the aim of examining the spectral characteristics of arc-voltage and arc-current pulsations in the plasmatron operated with 100-kW sectioned IEI, temporal realizations of signals about 13 ms long were recorded using a two-channel high-speed ADC. The sampling time of the input analog signals was chosen to be 400 ns. The signals were recorded in the range of operating currents from 160 to 300 A at standard preset flow rate values of various plasma-forming gases (air, argon, nitrogen, carbon dioxide gas) and varied flow rate values of the gases (argon, methane) that shielded the anode from the high-temperature gas flow. The arc-voltage and arc-current fluctuation spectra were calculated with the help of the fast Fourier transform of recorded signals. An analysis of arc-voltage fluctuations has showed that the high-frequency region of the spectrum (> 50 kHz) contained almost no harmonics, with a predominant fraction of the power spectrum of the fluctuations being concentrated in the frequency region below 20 kHz. At all values of regime parameters of the combined d.c. supply, the arc-current spectrum remained unchanged within 300 Hz. Figure 2 shows the spectra and the time traces of arc-voltage fluctuations over 1-ms time interval obtained at a fixed rate of the plasmaforming gas (nitrogen) GN2 = 1.5 g/s (without supply of shielding gas) for arc currents 160, 220, and 300 A. The voltage over the ordinate axis in Figs. 2b, 2d, and 2f is expressed in ADC readings. It is a well-known fact that the spectral region below 1-kHz frequency features the phenomenon of large-scale arc shunting over the anode channel. An analysis of the spectra has shown that, except for the harmonic due to the fluctuations of supply current, the fluctuations due to the axial displacements of the arc were small in magnitude, such a situation being typical of all operating regimes of the plasmatron. The characteristic times of arc fluctuations in the vicinity of the fixation spot of the arc on the anode (small-scale shunting) referred to the frequency range 1 to 20 kHz. Figure 2 illustrates rather profound a suppression of the harmonic amplitude in that region at increased arc
Fig. 2. Voltage traces recorded at moderate arc currents and voltages. а, b ⎯ 160 A and 346 V; c, d ⎯ 220 A and 335 V; e, f ⎯ 300 A and 331 V.
644
Thermophysics and Aeromechanics, 2014, Vol. 21, No. 5
currents. The latter suppression can be attributed to the stabilization of arc column length occurring due to the preferable fixation of the arc at the inlet of the anode. The arc fixation leads to reduced amplitude of large-scale voltage pulsations across the arc. 2.2. The structure and physico-mechanical properties of the plasma-sprayed heat-resistant Ni-Co-Cr-Al-Y intermetallic coatings In developing the heat-resistant coating intended for the protection of the turbine blades of gas-turbine engines against gas corrosion, PNKh20C20Yu13-1 powder mixture with particle dispersiveness 40/80 μm was used. The chemical composition of the mixture is indicated in Table 1. The material referred to the system Ni-Al. It differed from the class of thermo-reacting powders in that it was obtained by the powder-metallurgy method using vacuum sintering and subsequent crushing; it therefore already contained an intermetallic phase. By means of x-ray diffraction analysis, it was found that the most abundant phase in the powder material was the intermetallic compound β ⎯ (Ni, Ме) Al (Table 2). The cobalt and chromium doping impurities contained in the alloy were in a solid solution, and they, therefore, did not produce individual reflections in the x-ray diffraction patterns. That is why for a β-phase containing several doping impurities, the designation (Ni, Ме) Al is normally used, where Ме stands for the metal doping impurities forming a substitutional solid solution [8]. The coating obtained by the standard plasma spray technique exhibited a two-phase composition; namely, it involved the intermetallic compositions β ⎯ (Ni, Ме) Al and γ ′ ⎯ (Ni, Me)3 Al (Table 2) [8]. The formation of the γ ′-phase in the coating was a result of the phase transformation β → γ ′ proceeding due to the heating of the material in the plasmatron. Table 1 Chemical composition of the PNKh20C20Yu13-1 powder mixture Element Amount, wt %
Ni
Cr
Co
Al
Fe
Y
Ca
Nb
Mn
C
S
Si
Main
18.9
22.4
14.0
0.15
0.09
0.06
0.14
0.01
0.15
0.006
0.51
Table 2 X-ray diffraction data of the PNKh20C20Yu13-1 powder mixture and intermetallic coatings sprayed from the system Ni-Co-Cr-Al-Y on the standard and rebuilt equipment I, arb. units (hkl) Phase 2θ, deg d, А° 31.3 2.855 0.09 (100) β ⎯ (Ni,Ме)Al 44.8 2.023 1 (110) β ⎯ (Ni,Ме)Al PNKh20C20Yu13-1 (40/80 μm) 65.1 1.430 0.11 (200) powder mixture β ⎯ (Ni,Ме)Al 82.45 1.169 0.19 (211) β ⎯ (Ni,Ме)Al 99.2 1.013 0.10 (220) β ⎯ (Ni,Ме)Al 43.496 2.083 0.22 (111) γ′ ⎯ (Ni,Ме)3Al 44.554 2.034 1 (110) β ⎯ (Ni,Ме)Al 50.963 1.793 0.17 (200) β ⎯ (Ni,Ме)3Al Ni-Co-Cr-Al-Y coating obtained by 64.965 1.435 0.12 (200) the standard plasma spray technique β ⎯ (Ni,Ме)Al implemented on the UPU-3D facility 74.797 1.27 0.10 (220) γ′ ⎯ (Ni,Ме)3Al 82.265 1.171 0.18 (211) β ⎯ (Ni,Ме)Al 91.226 1.078 0.08 (311) γ′ ⎯ (Ni,Ме)3Al 43.496 2.083 0.43 (111) γ′ ⎯ (Ni,Ме)3Al Ni-Co-Cr-Al-Y coating obtained 44.554 2.034 1 (110) β ⎯ (Ni,Ме)Al by the modified spray technique (on 50.963 1.793 0.17 (200) γ′ ⎯ (Ni,Ме)3Al the facility equipped with the PNK-50 64.965 1.435 0.12 (200) β ⎯ (Ni,Ме)Al plasmatron) 74.797 1.27 0.10 (220) γ′ ⎯ (Ni,Ме)3Al 82.265 1.171 0.18 (211) β ⎯ (Ni,Ме)Al 91.226 1.078 0.08 (311) γ′ ⎯ (Ni,Ме)3Al 2θ ⎯ Bragg angles, d ⎯ interplanar spacing, I ⎯ reflection intensity, (hk1) ⎯ crystallographic (Miller) indices. Material
645
Yu.P. Tarasenko, I.N. Tsareva, O.B. Berdnik, Ya.A. Fel, V.I. Kuzmin, A.A. Mikhalchenko , and E.V. Kartaev
Fig. 3. Derivatogram of the PNKh20C20Yu13-1 powder mixture. SM ⎯ relative change of sample mass, DSC ⎯ differential scanning calorimetry, ex ⎯ exothermic reaction.
The derivatographic study has shown that this phase transition started at 900 °С (Fig. 3). In the plasma spray technique implemented on the rebuilt facility, a two-phase coating formed as well: β + γ ′⎯ (Ni, Ме) Al + (Ni, Me)3 Al. In the latter case, an increase in the temperature to which the powder mixture was heated led to increased γ ′-phase content of the coating (Table 2). The microstructure of the intermetallic coating obtained by the standard plasma spray technique is shown in Fig. 4. From the photos, it is seen that, in this process, a round-grain structure formed (Fig. 4а). In the metallographic sections of the coating (Fig. 4b), a loose grain structure featuring boundary discontinuities and rather large voids with sizes reaching 30 μm was observed. The structure of the intermetallic coating obtained on the rebuilt equipment is shown in Fig. 5. Onto the substrate surface, the material comes in dispersed state (in the form of fine melted or plasticized particles, which, as they impinge onto the substrate, undergo deformation). Stuck to the substrate, the new particles overlap the previously deposited particles to form a coating with lamellar microstructure. The elongated shape of the grains is due to the high kinetic energy of the particles in the high-power plasmatron. The coating contains round-shaped particles that had already solidified prior to their fall onto the substrate and penetrated into the substrate due to their high kinetic energy. The thickness of the coating is 200−240 μm (Fig. 5b). The voids range in size in the interval 5 to 10 μm, with no throughporosity being observed. At the coating-substrate interface, no defects in the form of chip, discontinuities, and exfoliations are observed either.
Fig. 4. The microstructure of the Ni-Co-Cr-Al-Y intermetallic coating obtained by the standard spray technique on the UPU-3D facility. а ⎯ surface, b ⎯ cross section (Х500).
646
Thermophysics and Aeromechanics, 2014, Vol. 21, No. 5
Fig. 5. Microstructure of the metallographic section of a Ni-Co-Cr-Al-Y intermetallic coating obtained by the modified technology implemented using a PNK-50 plasmatron. а ⎯ Х1000, b ⎯ Х125.
By means of electron microscopy, it was found that the grain boundaries were enclosed by oxide phase inclusions (Fig. 6а). An analysis of the distribution of elements in samples has shown that, at the grain boundaries, simultaneous rise of the reflection intensities due to oxygen, aluminum, and chromium was observed (Fig. 6b). The latter observation points to the oxidation processes proceeding together with the formation of the intermetallic coating with aluminum and chromium oxide inclusions. Testing the coating by the micro-indentation technique has confirmed its satisfactory adhesion strength. As result of indentation of the coatingsubstrate interface, no exfoliations, chips, cracks, and deformations of the imprint of indenter were detected (Fig. 7). Results of the heat-resistance tests are graphically shown in Fig. 8. It should be noted that, here, the curves for the samples with uncoated heat-resistant EI 893 nickel alloy lie in the negative region. At an early stage of high-temperature oxidation (during the first 50 hours), vigorous formation of loose oxides was observed on the metallic surface, those oxides exhibiting exfoliation from the oxidized surface. That is why at the beginning of the tests, the sample
Fig. 6. The grain microstructure (а) and the distribution of elements (b) in the Ni-Co-Cr-Al-Y intermetallic coating obtained on the rebuilt equipment. 647
Yu.P. Tarasenko, I.N. Tsareva, O.B. Berdnik, Ya.A. Fel, V.I. Kuzmin, A.A. Mikhalchenko , and E.V. Kartaev
Fig. 7. The interface between the substrate and the Ni-Co-Cr-Al-Y coating obtained on the rebuilt equipment (Х400).
Fig. 8. Relative variation of sample mass during heat-resistance tests versus the time of sample storage at fixed temperature. Samples of the heat-resistant EI 893 nickel alloy without coating (1) and samples of the heat-resistant EI 893 nickel alloy with Ni-Co-Cr-Al-Y coatings obtained using the standard (2) and modified (3) spray techniques.
mass showed a sharp reduction. After a 100-hour anneal, a permanent growth of the oxide layer and its exfoliation from the surface was observed. The samples with the Ni-Co-Cr-Al-Y intermetallic coating obtained by the standard plasma spray technique exhibited a behavior in terms of the time variation of its mass similar to that displayed by the uncoated samples. The curve for the samples with the Ni-Co-Cr-Al-Y intermetallic coating obtained on the rebuilt equipment lies in the positive region. During the first 50 hours, oxide-layer formation accompanied with an increase of sample mass was observed. Over the next 100 hours, a decrease of the mass due to partial exfoliation of the coating was detected. After 300 hours, the curves come to saturation, which observation points to the formation of a stable oxide layer capable of serving the protective function. The performed tests have shown that the developed coatings improve the stability of nickel alloys against high-temperature oxidation. The coatings obtained by the modified plasma spray technique are most effective in terms of their resistance to heat. The electron microscopy study (see Fig. 9) showed that the coating preserved its integrity both at the surface acted upon by the aggressive ambient medium and over the cross section, with no exfoliations at the interface with the underlying material being detected. After the tests, the coating was uniform over its thickness, with its lamellar grain structure having remained unchanged. Comparative figures of merit of the physico-mechanical properties of the Ni-Co-Cr-Al-Y intermetallic coatings obtained by the two plasma spray techniques are indicated in Table 3. Note that the increase in the content of the γ ′-phase, (Ni, Me)3 Al, occurring during plasma spraying can affect the service properties of the heat-resistant coatings. On the one hand, Table 3 Physico-mechanical properties of the Ni-Co-Cr-Al-Y intermetallic coatings obtained on the standard and rebuilt plasma spray setups Physico-mechanical properties of the coatings Total porosity P, % Closed-type porosity Pc, % Open-type porosity P0, % 3
Density ρ, g/cm 2 Microhardness Hμ, kg-force/mm
648
Standard spray technique
Modified spray technique
7.3 6.6 0.7 7.3 300
5.7 5.1 0.6 7.9 770
Thermophysics and Aeromechanics, 2014, Vol. 21, No. 5
Fig. 9. Microstructure of the metallographic section of the heat-resistant Ni-Co-Cr-Al-Y coating after 500-hour annealing. а ⎯ Х1000, b ⎯ Х 5000.
an increase in the amount of this phase enhances the sample hardness. On the other hand, it is a well-known fact that deterioration of the protective properties of the heat-resistant coatings exploited under high temperatures proceeds according to the following mechanism: β → β + γ ′ → → γ ′→ γ-solid-solution-Ni + oxides [8]. That is why it can be expected that an increase in the amount of the γ ′-phase in the modified plasma spray process will reduce the service life of the coating. Yet, from the viewpoint of coating quality, the determining factor is the porosity. A decrease of porosity will diminish the access of aggressive ambient medium into the coating, and it will, therefore, prevent the coating from reaching an early failure. Since the temperature of the plasma flow is a parameter hard to regulate, then the (Ni, Me)3 Al-phase content of the coating is currently also a parameter difficult to control. The modified plasma spray technique has allowed us to obtain an intermetallic coating with reduced porosity and with enhanced density, microhardness, and heat-resistance indicators. The developed process was introduced at YakutskEnergo Open Joint Stock Company for prolonging the service life of rotor and guide blades of GTE-35-770-2 and GTE-45-3 gasturbine apparatuses used at heat power plants. The operating experience has shown that the developed coatings preserved their integrity and provided reliable functioning of turbine blades over a period of 24 000 hours. Conclusions 1. As a result of the modification of the plasma spray technique achieved via using the improved PNK-50 plasmatron with enhanced power, we have developed a heat-resistant Ni-Co-Cr-Al-Y coating with (β + γ ′) intermetallic phase composition and lamellar grain structure. 2. Due to the improved effectiveness of the plasma spray technique, formation of a denser 3 intermetallic coating (ρ = 7.9 g/cm ) with reduced porosity values (total porosity P = 5.7 %, open-type porosity P0 = 0.6 %), possessing approximately two times increased microhardness and heat-resistance indicators in comparison with coatings obtained by means of the standard plasma spray technique, has been achieved. 3. The new Ni-Co-Cr-Al-Y intermetallic coatings can be recommended for protection of turbine engine blades of various designations against high-temperature gas corrosion and for prolonging the service life of such blades. 4. The developed coatings were introduced at the Yakutsk Energo Open Joint Stock Company for prolonging the service life of rotor and guide blades of GTE-35-770-2 and GTE45-3 gas-turbine apparatuses used at heat power plants. 649
Yu.P. Tarasenko, I.N. Tsareva, O.B. Berdnik, Ya.A. Fel, V.I. Kuzmin, A.A. Mikhalchenko , and E.V. Kartaev
References 1. L.Kh. Baldaev, Renovation and Strengthening of Machine Parts by Thermal Spraying Methods, KKhT Publishing House, Moscow, 2004. 2. Yu.P. Tarasenko, O.B. Berdnik, I.N. Tsareva, and Ya.A. Fel, Enhancement of the reliability and service life of turbine blades in gas-pumping apparatuses, in: Proc. Anniversary Conf. “Problems in Machine Building”, Institute of Engineering Science RAS, Moscow, 2008, P. 528−531. 3. Patent No. 88389, Russian Federation, MPK6 F27B15/00. Turbine blade with a heat-resistant coating for gasturbine engines / Yu.P. Tarasenko, I.N. Tsareva, Ya.A. Fel, and O.B. Berdnik, Applicant: Tribonika Scientific and Production Center, No. 2009125740. 4. Patent No. 2474983, Russian Federation, MPK Н05В7/22. Unit for circular input of powder materials of electricarc plasmatorch / V.I. Kuzmin, A.A. Mikhalchenko, and E.V. Kartaev; Applicant: Khristianovich Institute of Theoretical and Applied Mechanics, Russian Academy of Science, Siberian Branch, No. 2011128160/07; application date 07.07.2011; publication date 10.02.2013, Bulletin of Inventions and Useful Models, No. 4, 2013. 5. C. Baudry, A. Vardelle, G. Mariaux, C. Delalondre, and E. Meillot, Three-dimensional and time-dependent model of the dynamic behavior of the arc in a plasma spray torch, in: Proc. ITSC’04, May 10–12, 2004, Osaka, Japan, Р. 717−723. 6. M.F. Zhukov, A.S. Anshakov, and I.M. Zasypkin, Electric-Arc Generators with Inter-Electrode Inserts, Nauka, Novosibirsk, 1981. 7. J.F. Bisson, B. Gauthier, and C. Moreau, Effect of plasma fluctuations on in-flight particle parameters, J. Thermal Spray Technology, 2003, Vol. 12, Iss. 1, Р. 38−43. 8. Yu.R. Kolobov, E.N. Kablov, E.V. Kozlov, N.A. Koneva, and K.B. Povarova, Structure and Properties of NanoPhase Reinforced Intermetallic Materials, MISiS Publishing House, Moscow, 2008.
650
