ISSN 1070-4272, Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 8, pp. 1235−1242. © Pleiades Publishing, Ltd., 2013. Original Russian Text © K.V. Murzenko, Yu.D. Kudryavtsev, V.I. Balakai, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 8, pp. 1261−1268.
ELECTROCHEMISTRY AND OTHER PROCESSES OF CHEMICAL TECHNOLOGY
Properties of Composite Nickel–Cobalt–Aluminum Oxide Coating Deposited from Chloride Electrolyte K. V. Murzenko, Yu. D. Kudryavtsev, and V. I. Balakai South-Russian State Technical University, Novocherkassk, Rostov-on-Don oblast, Russia e-mail:
[email protected] Received December 21, 2012
Abstract—Effect of the cathodic current density, pH value, electrolyte temperature, and concentration of aluminum oxide introduced into the electrolyte on the wear, microhardness, and internal stresses in nickel–cobalt–aluminum oxide composite electrolytic coatings was studied. It is shown that the coatings under consideration can be used instead of chromium coatings. DOI: 10.1134/S1070427213080144
Use of composite electrochemical coatings (CEC) makes it possible to improve the reliability and durability of new and restored machine components. In addition, with composite electrochemical coatings used, it is frequently possible to replace deficient alloyed steels and cast irons with less expensive grades of metals. Composite electrochemical coatings containing hard oxides, carbides, and nitrides of metals as a second phase are used to impart to machine component surfaces necessary mechanical properties: hardness, wear resistance, corrosion resistance, and high-temperature strength. CECs based on nickel and iron have been primarily developed for replacing wear-resistant chromium coatings and some of these have found application in automobile industry. The conventional chromium-plating process can yield hard chromium coatings possessing good physicomechanical properties, such as the corrosion resistance, wear resistance, hardness, and low friction coefficient. However, chromium-plating electrolytes based on hexavalent chromium salts have serious disadvantages. To these belong the low throwing power (TP), high toxicity of chromium-plating electrolytes, extremely low current efficiency (CE) in electrodeposition of chromium coatings, and decrease in hardness at elevated temperatures. In addition,
the standard chromium-plating electrolytes based on chromic acid are among the most noxious electrolytes in modern industries. Their replacement with electrolytes based on trivalent chromium salts is not a solution because these electrolytes are also toxic. Moreover, coatings deposited from the so far developed electrolytes cannot replace those produced from the standard chromium-plating electrolytes primarily in those fields of technology where the functional properties of chromium coatings and their high wear resistance are required. A study of the dry-friction wear of coatings has shown that CECs with aluminum oxide are markedly advantageous over other kinds of coatings. For example, the wear rates of pure electrolytic iron, iron–boron carbide deposits, and iron–aluminum oxide deposits at a contact pressure of 8.1 MPa were, respectively, 91, 9.4, and 5 mg h–1. The seizure and wear of iron–titanium carbide coatings were observed already in the first minutes of their service under a pressure of 4.0 MPa. First indications of seizure (consisting in fluctuations of the friction momentum) were observed for hard electrolytic iron (microhardness 5.8 GPa) at a pressure of 5.5 MPa. However, the thin layer of oxides, present on the coating surface, precluded intense seizures and scuffing of
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surfaces [1]. The electrolytic iron and iron-based CECs form, upon 20 min of dry friction with a mated cast iron plate under a specific pressure of 15 MPa, scuffs on the coating surface, which leads to a substantial wear of the coating and the mated surface. The iron–corundum coating forms no scuffs in dry friction at a specific pressure of 25 MPa. Studies of the wear resistance of iron-based CECs produced from a chloride electrolyte with addition of powdered corundum have shown that, in the presence of 4–8 wt % inclusions, the wear of the coating falls by more than a factor of 4–5, and the friction coefficient decreases from 0.1 to 0.02. Coatings optimal in wear resistance contained 1–6 wt % corundum. Coatings of this kind have been recommended for industrial use for reinforcement of machine components [2]. In [3], the possibility of obtaining and mechanical properties of CECs of varied nature, containing particles of chromium, titanium, silicon, boron, and vanadium carbides, poly(vinyl chloride), and polycrystalline and single-crystal diamond, were considered. Particular attention was paid to data on the wear resistance of coatings based on nickel–boron and nickel–phosphorus alloys. Introduction of Al2O3, SiC, diamond, and polycrystalline diamond particles into chemically deposited nickel–boron coatings can reduce the wear rate of coatings by, respectively, factors of 90, 200, 2000, and 4000. It was concluded that application of these coatings in conditions of both dry and lubricated friction is highly promising. Nickel coatings with corundum particles have high corrosion and wear resistance [4]. According to [5], Al2O3 particles incorporated into the nickel matrix shield its surface and thereby reduce the corrosion rate. The goal of our study was to examine properties of nickel–cobalt–aluminum oxide composite electrochemical coatings deposited from a chloride electrolyte and the possibility of their application as wear and corrosion resistant coatings. EXPERIMENTAL The current efficiencies by the Ni–Co–Al2O3 CEC and hydrogen were determined by the procedure described in [6]. The throwing power of the electrolytes was determined using the Haring–Blum procedure [7].
The microhardness of the coatings was measured with a PMT-3 microhardness meter at a constant indenter load of 100 g on 15 × 15 × 1 mm steel samples (coating thickness no less than 20 μm). In each case, no less than two parallel runs were performed in order to obtain reproducible experimental data. Five measurements were made on each sample. The samples were kept under load for 10 s, with the indenter lowering and raising time being not less than 15 s. The coating wear was determined on a friction machine designed at Orion experimental design bureau (Novocherkassk). The samples were tested both in the dry-friction mode and with 3% SOZh RV lubricant by a special procedure [8]. As samples served ShKh steel balls with an area of 0.05 dm2, on which 30-μm-thick coatings were deposited. The role of a counter body was played by St.45 steel washers. The wear spot diameters were measured with a MIR microscope. The internal stresses in the coatings were determined by the flexible-cathode method [9]. A thin (0.012 cm) 4 × 2 cm steel plate served as the cathode. The upper end of the cathode was firmly fixed and the side opposite to the anode was insulated. A tungsten wire with a diameter of 0.5 mm and length of 7–10 cm was fixed on the same side with a lacquer to determine the cathode bend. The position of the tungsten wire was determined with the MIR microscope prior to electrolysis. The change in the position of the wire in the course of electrolysis was used to find the cathode bend. The internal stress of a coating was calculated by the formula ВН = (Ed2z)/(3δl2),
where E is the elastic modulus of steel (MPa); d, cathode thickness (m); z, cathode bend (m); δ, coating thickness (m); and l, cathode length (m). The porosity of nickel-coated steel plates was determined by the method of filter paper application in conformity with GOST (State Standard) 9.302–88. The sample size was 15 × 15 × 1 mm, the substrate material was 12 μm. The corrosion resistance of the coatings was determined by the Corrodcote method [9]. The corrosion damage rate was evaluated by the area occupied by corrosion spots [10]. The content of the dispersed phase in a coating was determined gravimetrically. Its 300-mg portion was dissolved in 150 mL of concentrated nitric acid. After
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the weighed portion of the coating was dissolved and the acid was cooled, it was diluted with distilled water in a 1 : 1 ratio. The solution was filtered through an ultradisperse filter with a known mass. After the solution was filtered, the filter was dried and again weighed. The content of aluminum oxide in a coating was determined in weight percent. RESULTS AND DSCUSSION Electrolytic coatings based on the Ni–Co alloy are used in machine-building industries to prolong the service life and to restore machine components. These coatings are distinguished by increased hardness and high corrosion and wear resistance. To improve the wear and corrosion resistance, it was suggested to additionally introduce aluminum oxide into the chloride electrolyte intended for deposition of the Ni–Co alloy. Solid oxide particles improve the wear resistance of CECs in operation of mated articles in lubricated or dry friction and substantially diminish the scuffing of the rubbing surface. As a result of the study, an electrolyte of the following composition for deposition of Ni–Co–Al2O3 CECs was developed (g L–1): nickel chloride hexahydrate 200–350, cobalt sulfite heptahydrate 3–15, boric acid 25–40, chloramine B 1.5–4.0, aluminum oxide 10–40; pH 1.0–5.0. Electrolysis modes: temperature 20–60°C, cathode current density 1–15 A dm–2, agitation at 80–120 rpm [11]. To improve the wear and corrosion resistance, 1,4-butinediol was additionally introduced into the given electrolyte, with saccharine used instead of chloramine B. The study was performed in the electrolyte of composition (g L–1): nickel chloride hexahydrate 250, cobalt sulfite heptahydrate 10, boric acid 30, saccharine 1.5, 1,4-butinediol 0.3, aluminum oxide 10–40; at pH 4.0, temperature of 20°C, cathode current density of 6 A dm–2 under agitation at 100 rpm, unless otherwise specified. The electrolyte was prepared as follows. Boric acid, nickel chloride, cobalt sulfite, and saccharine were dissolved at a temperature of 60–70°C in an electroplating bath filled to 3/4 of the required volume with tap water. After that the electrolyte level was brought to the required volume and aluminum oxide (dispersity 0.1–0.25 mm) was introduced. The electrolyte pH was adjusted by addition of hydrochloric acid or a NaOH
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(KOH) solution (100–150 g L–1). The difficulties in reduction of iron-group metal ions are due to the adsorption of foreign particles (solvent molecules, oxygen, hydrogen, hydroxides) on the electrode surface. Depending on the nature of an electrode and on the firmness of adherence of foreign particles to the electrode surface, the work required to remove these particles will vary. It was shown in [2] that, in mechanical removal of foreign particles from the cathode in nickel plating, there occurs disintegration of the film formed on the cathode surface by hard particles, with the resulting decrease in the electrode polarization. It was noted that the electrode depolarization is due to the mechanical effect of the particles on the electrode surface. The electrode depolarization also occurs in the presence in the electrolyte of “soft” particles, e.g., of fluoroplastic [13], which cannot scratch and activate the electrode and destroy the film formed. Therefore, it is impossible to unambiguously state that the particles have a depolarizing effect. In this context, we performed a study to reveal the effect of aluminum oxide particles moving at the cathode on the electrode polarization. Nickel was used as the material of substrate electrodes. The role of the dispersed phase was played by aluminum oxide capable of mechanically activating the electrode surface. The change in the electrode potential in the chloride electrolyte for deposition of the Ni–Co alloy and Ni–Co– Al2O3 CECs at the initial instant of time was measured with a P-5848 potentiostat and S1-19 oscilloscope. Our experiments demonstrated that, after a dc current was switched on, a steep rise in the electrode potential was observed, followed by its decrease to a certain constant value, both with and without introduction of aluminum oxide into the electrolyte for deposition of the nickel–cobalt alloy. However, the electrode potential decreased in the presence of the suspension to a greater extent than that in the pure electrolyte for deposition of the nickel–cobalt alloy. Presumably, aluminum oxide particles facilitate the electrode process and shift the cathodic polarization curve to the positive region (Fig. 1) as a result of the electrode depolarization by moving particles and delivery of metal ions to the electrode by these particles. Without agitation, i.e., under the natural sedimentation
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j, A dm–2
–E, V Fig. 1. Potentiometric dependences for deposition of (1) Ni– Co–Al2O3 and (2) Ni–Co coatings.
of a disturbed suspension, the electrode polarization increases. This is due to the blocking of the electrode surface by the particles. The agitation of the suspension, on the whole, makes higher the limiting current and diminishes the polarization, which is due to the delivery of metal ions to the cathode by particles and to the disintegration of the film of substances adsorbed on the cathode. The mechanism by which galvanic coatings dispersion-reinforced with particles of widely diverse powdered materials is known. However, a steadily increasing attention, caused by the growing interest in nanotechnologies, has been paid recently to galvanic coatings obtained using extremely high dispersity powders. The following mechanisms of CEC reinforcement, directly determined by properties of the dispersed phase, can be distinguished. The overgrowth of comparatively coarse particles (10–50 μm) [14] gives rise to compression stresses around these particles and, as a result, to a certain improvement of the properties of the coatings themselves. It should be noted that difficulties are encountered in deposition of coatings of this kind because particles with this extent of dispersion have low sorption capacity are poorly mobile in suspension, and distort electromagnetic field lines on deposition surfaces. This set of disadvantages rapidly resulted in that researchers’ attention was focused on powder with high degree of dispersity (1–5 μm). In this case, the coating reinforcement mechanism is based on the following hypotheses: formation of nonuniform fields of internal stresses, blocking of the crystal growth, and incorporation of powder particles into a coating in the form of additional crystallization centers. Presumably, each of these mechanisms is operative in
a growing coating with varied degree of intensity and, apparently, certain properties of the dispersed phase are to be provided for each of these mechanisms to become operative. A finer fraction (0.1–1 μm) will block growth of coarse crystals, act as electrocrystallization centers, and promote formation of a finely crystalline structure of the coating. In this case, the coating formation mechanism can be represented as follows. As also in the case of deposition of unreinforced coatings, a CEC nucleus will grow in a plane parallel to the substrate, which is manifested in a layer-by-layer formation of galvanic coatings. However, being incorporated into the coating, particles of the dispersed phase become a part of the cathode and further electrocrystallization will occur from their surface. Thus, the work of coating growth in the direction perpendicular to the substrate becomes substantially lower. If a sufficient amount of particles is adsorbed on the cathode, the coating growth in this direction becomes markedly faster and formation of spheroids is suppressed. Therefore, the mechanism of CEC formation is affected not only by the electrolyte composition, component concentrations in the electrolyte, and electrolysis modes, but also by the composition, structure, and dispersity of the particles, which, in turn, exert influence on the physicomechanical properties of coatings being deposited. Because the Ni–Co–Al2O3 coating is being developed as a wear-resistant coating, we studied how the wear resistance depends on the content of aluminum oxide in the electrolyte, temperature, cathode current density, pH value of the electrolyte, and load on rubbing contacts. The obtained dependence of the wear of Ni–Co–Al2O3 CECs on the concentration of aluminum oxide in the electrolyte and the loads on rubbing contacts is shown in Fig. 2. It can be seen in Fig. 2a that the wear of a Ni–Co– Al2O3 CEC decreases from 0.28 to 0.25 μm h–1 with the aluminum oxide concentration in the electrolyte increasing from 10 to 20 g L–1. With the concentration raised further, from 20 to 30 g L–1, the wear remains nearly unchanged, and upon an increase in the concentration to 50 g L–1, the wear grows to 0.29 μm h–1. With the load raised from 1 to 30 MPa, the wear increases from 0.25 to 0.32 μm h–1. In the process, the wear becomes only slightly higher upon an increase in the load from 1 to 20 MPa, and grows sharply with the
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PROPERTIES OF COMPOSITE NICKEL–COBALT–ALUMINUM OXIDE A, μm h–1
H, GPa
(a)
c, g L–1 A, μm h–1
(b)
P, MPa Fig. 2. Wear resistance A of Ni–Co–Al2O3 coatings vs. (a) concentration c of aluminum oxide in the electrolyte at a loads of 5 MPa and (b) load P on the rubbing articles.
load raised further (Fig. 2b). All other conditions being the same, an increase in the electrolyte temperature from 20 to 60°C leads to a slight decrease in the wear from 0.25 to 0.23 μm h–1, and on raising the cathode current density from 2 to 10 A dm–2, the wear grows from 0.23 to 0.28 μm h–1. A change in the electrolyte pH from 1 to 4 hardly affects the wear of the coating (0.24–0.25 μm h–1), whereas on raising the pH value to 5, the wear sharply grows (0.28 μm h–1). The wear resistance of Ni–Co–Al2O3 CEC under a load of 2 MPa on rubbing contacts is approximately three times that of chromium (1.1–1.2 μm h–1) deposited from the electrolyte containing (g L–1): chromium anhydride 250 and sulfuric acid 2.3, at a temperature of 60°C and cathode current density of 60 A dm–2 [16]. This enable use of Ni–Co–Al2O3 CECs as wear-resistant coatings in machine-building industries instead of chromium coatings. The dependences of the microhardness of Ni–Co– Al2O3 CECs on the concentration of aluminum oxide in the electrolyte and on the solution pH at various
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(a)
c, g L–1 H, GPa
(b)
Fig. 3. Microhardness H of the Ni–Co–Al2O3 coating vs (a) concentration c of aluminum oxide in the electrolyte and (b) electrolyte pH. Temperature (°C): (1) 20, (2) 40, and (3) 60; the same for Fig. 4.
electrolyte temperatures are shown in Fig. 3. It can be seen in Fig. 3a that the microhardness grows as the concentration of aluminum oxide is raised from 10 to 50 g L–1. For example, the microhardness increases from 8 to 10 GPa at a temperature of 20°C. With the electrolyte pH raised from 1 to 3 at a temperature of 20°C, the coating microhardness decreases from 9.5 to 8.7 GPa; with the pH value raised further, to 5, the microhardness increases to 10 GPa (Fig. 3b). All other conditions being the same, raising the electrolyte temperature from 20 to 60°C and the cathode current density from 2 to 10 A dm–2 leads to a decrease in the microhardness from 8 to 7.5 GPa and from 9.5 to 8.5 GPa, respectively. The microhardness and wear of Ni–Co–Al2O3 CECs depend on various factors because, as the content of aluminum oxide in the electrolyte increases, so does its content in the deposit, which leads to a higher microhardness and lower wear of a coating. If, however, the content of aluminum oxide in the electrolyte becomes higher than 30 g L–1, the wear of a coating grows due to its poorer quality and larger roughness of its surface.
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Raising the load on rubbing articles leads to a stronger wear of coatings because of the larger friction force and stronger heating of article surfaces. At load higher than 20 MPa, the wear grows faster, possibly because of the dislodging of alloying components from the coatings. As the cathode current density is raised, the alkalization of the ear-cathode layer becomes more pronounced because the pH of the onset of nickel and cobalt hydration is reached in this layer, which favors incorporation of not only aluminum oxide, but also nickel and cobalt hydroxides into the coating. In this case, the content of aluminum oxide in a coating decreases and its quality is deteriorated, which leads to a lower microhardness and larger wear of the coating. As the electrolyte temperature is raised, the degree of nickel and cobalt hydrolysis in deposition of Ni–Co– Al2O3 CEC becomes larger and colloid particles based on these compounds are more finely dispersed, their larger amounts are formed [17], they are more homogeneously distributed in a coating, and thereby the incorporation of aluminum oxide into the coating is diminished, which results in a decrease in the microhardness and increase in the wear resistance. With increasing electrolyte pH, the microhardness first decreases only slightly, with the wear remaining nearly unchanged. With the pH value in the bulk of the electrolyte raised further, to above 4, nickel and cobalt hydrates start to be formed in the electrolyte. This leads to formation of colloidal and microheterogeneous particles [17], which may also lead to an increase in the supply of aluminum oxide and to their higher content in a coating. Therefore, the microhardness of the coating grows, and so does its wear because of the poorer quality of the coating. The throwing power of the electrolyte for deposition of wear-resistant CECs is an important parameter, which enables us to assess the possibility of using the coating for deposition on complex-configuration articles. The results obtained in a study of the TP in relation to the concentration of aluminum oxide in the electrolyte and to the cathode current density at various temperatures are presented in Fig. 4. With the concentration of aluminum oxide in the electrolyte increasing from 10 to 50 g L–1, the TP at a temperature of 20°C decreases from 32 to 17% (Fig. 4a).A similar run is observed for the dependence of the TP on the cathode current density. For example, an increase in the cathode current density from 2 to 10 A dm–2 results in that the TP decreases
TP, %
(a)
c, g L–1 TP, %
(b)
j, A dm–2 Fig. 4. Throwing power TP of the electrolyte vs. (a) concentration c of aluminum oxide in the electrolyte and (b) cathode current density j.
from 22 to 16% (Fig. 4b). The decrease in the TP of the electrolyte with increasing concentration of aluminum oxide in the electrolyte is attributed to the additional agitation of the difficultly stirred part of the nearelectrode layer. Similarly, an additional agitation of the near-electrode layer is possible upon an increase in the current density due to the formation of difficultly soluble nickel compounds in the electrolyte. On raising the temperature of the electrolyte from 20 to 60°C, its TP grows from 17 to 23%. Raising the electrolyte pH from 1 to 5 results in a slight decrease in the TP of the electrolyte. It is known that internal stresses appear in plated coatings and these stresses may reach rather large values, which adversely affects the physicomechanical properties of the coatings and, in particular, makes poorer their wear resistance and protecting capacity. A study of Ni–Co–Al2O3 CECs by the flexible cathode method demonstrated that compression stresses appear in the coatings. Figure 5 shows how the internal stress depends on the content of aluminum oxide in the electrolyte and on the coating thickness. As the concentration of aluminum oxide in the
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PROPERTIES OF COMPOSITE NICKEL–COBALT–ALUMINUM OXIDE IS, MPa
(a)
c, g L–1 (b)
IS, MPa
δ, μm Fig. 5. Internal stress IS in a Ni–Co–Al2O3 coating vs. (a) concentration c of aluminum oxide in the electrolyte and (b) coating thickness δ. (a) Coating thickness (μm): (1) 10 and (2) 20. (b) Concentration of Al2O3 in the electrolyte (g L–1): (1) 0, (2) 10, (3) 20, and (4) 40.
electrolyte is raised from 10 to 50 g L–1, the internal stresses in Ni–Co–Al2O3 CECs decrease from 270 to 240 MPa at a 10-μm coating thickness (Fig. 5a). As a coating becomes thicker, the internal stresses decrease both for coatings based on the Ni–Co alloy and for Ni–Co–Al2O3 CECs. In coatings deposited from the electrolyte containing aluminum oxide, the internal stresses are substantially lower than those in coatings deposited from electrolytes without this additive (Fig. 5b). If a 20-μm-thick coating is deposited, an increase in the electrolyte temperature from 20 to 60°C results in that the internal stress decreases from 225 to 200 MPa. On raising the electrolyte pH from 1 to 4, the internal stress decreases from 260 to 225 MPa; as the pH value is raised further, to 5, the stress increases to 270 MPa at a coating thickness of 20 μm. With the cathode current
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density raised from 2 to 10 A dm–2, the internal stress grows from 220 to 240 MPa. The current efficiency by Ni–Co–Al2O3 CECs is within the range 99–107%. The current efficiencies exceeding 100% represent a distinctive feature of electrolytes containing finely dispersed particles involved in electrode processes, both introduced into the electrolyte and formed in the course of electrolysis. This occurs because the cathode deposit incorporates dispersed particles introduced into the electrolyte in the form of aluminum oxide and undischarged colloidal and microheterogeneous compounds of nickel. Composite coatings frequently have an increased corrosion resistance and protecting capacity. We performed corrosion tests of Ni–Co–Al2O3 CECs in comparison with the Ni–Co alloy. The tests were made on steel samples at a coating thickness of 30 μm. The coatings to be tested were deposited from electrolytes intended for deposition of a composite coating and the Ni–Co alloy. The table lists comparative data on the corrosion resistances of the coatings. Accelerated corrosion tests demonstrated that corrosion rate of Ni–Co–Al2O3 CECs is more than four times lower than that of Ni–Co alloys. CONCLUSIONS (1) A chloride electrolyte was developed for deposition of a wear-resistant Ni–Co–Al2O3 composite electrochemical coating. The electrolyte has the following composition (g L–1): nickel chloride hexahydrate 200–350, cobalt sulfite heptahydrate 8–15, boric acid 30–40, saccharine 1.0–2.0, aluminum oxide 10–40; 1,4-butinediol 0.3–0.8 mL L–1. Electrolysis modes: pH 1.0–5.0, temperature 20–60°C, cathode current density 2–10 A dm–2, agitation at 80–120 rpm [11]. (2) It was shown that, at a load of 2 MPa on the
Results of comparative corrosion tests Coating
Test duration, h
Changes in outward appearance
Corrosion damage area, %
Ni–Co
16
Coating has corrosion pits
15
Ni–Co–Al2O3
16
No changes
–
Ni–Co–Al2O3
32
No changes
–
Ni–Co–Al2O3
64
Coating has corrosion pits
3
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rubbing contacts, the wear resistance of the Ni–Co– Al2O3 composite electrochemical coating deposited from the suggested electrolyte is approximately three times that of chromium. This fact enables replacement of wear-resistant chromium coatings with Ni–Co–Al2O3 composite coatings. (3) It was demonstrated that replacement of chromium-plating baths can extend the service life and improve the reliability of articles under abrasive conditions, improve working conditions, reduce the expenditure for wastewater neutralization, make unnecessary construction of sewage treatment works for chromium-containing discharges, and obtain a significant positive economical effect because of excluding the heating of the electrolyte and maintaining its temperature, lowering the bath voltage, and raising the throwing power of the electrolyte and the current efficiency by the coating being deposited. REFERENCES
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1. Gur’yanov, G.V., Elektroosazhdenie iznosostoikikh kompozitsionnykh pokrytii (Deposition of Wear-Resistant Coatings), Kishinev: Shtiintsa, 1985. 2. Ryabikhin, A.S., Suvorin, A.V., and Petukhov, R.A., Abstracts of Papers, 13-aya Mezhdunarodnaya nauchnoprakticheskaya konferentsiya studetov, aspirantov i molodykh uchenykh “Sovremennye tekhnika i tekhnologii 2007” (13th nt. Sci.-Pract. Conf. of Students, Postgraduate Students, and Young Scientists “Modern Technology and Technological Methods 2007”), Tomsk: Sibirsk. Federal’n., Univ., 2007, pp. 67–68.. 3. Feldstein, N., The Emergence of Composite Electroless Coating, Proc. 77th AESF Annu. Tech. Conf., Boston, Mass., July 9–12, 1990, vol. 2, pp. 1227–1241.
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Prikl. Khim., 2010, vol. 83, no. 1, pp. 67–73. Praktikum po prikladnoi khimii (Laboratory Manual of Applied Chemistry), Kudryavtsev, N.T. and Vyacheslavov, P.M., Eds.,. Leningrad: Khimiya, 1973. Shul’ga, G.I., Metodicheskie ukazaniya po kursu “Tekhnologiya mashinostroeniya” (Methodological Recommendation for the Course “Technology of Machine Building”), Novocherkassk: Novocherkassk. Politekhn. Inst., 1989. Shmeleva, N.M., Kontroler rabot po metallopokrytiyam (Supervisor of Metal Coating Works), Moscow: Metallurgiya, 1966. Rozenfel’d, I.L. and Zhigalova, K.A., Uskorennye metody korrozionnykh ispytanii materialov (teoriya i praktika) [Accelerated Methods for Corrosion Tests of Materials (Theory and Practice)], Moscow: Metallurgiya, 1970. RF Patent 2418107. Saifullin, R.S., Neorganicheskie kompozitsionnye materially (Inorganic Composite Materials), Moscow: Khimiya, 1983. Arzumanova, A.V., Fundamental Aspects of Electrodeposition of Nickel–Fluoroplastic and Nickel–Boron– Fluoroplastic Composite Electrolytic Coatings from a Chloridfe Electrolyte, Cand. Sci. Dissertation, Novocherkassk, 2011. Borodin, I.N., Poroshkovaya gal’vanotekhnika (Powder Electroplating), Moscow: Mashinostroenie, 1990. Balakai, V.I., Arzumanova, A.V., Balakai, I.V., and Byrylov, I.F., Zh. Prikl. Khim., 2010, vol. 83, no. 12, pp. 2008–2012. Yampol’skii, A.M. and Il’in, V.A., Kratkii spravochnik gal’vanotekhnika (Electroplater’s Concise Handbook), Leningrad: Mashinostroenie, 1981. Balakai, V.I., Electrodeposition of Nickel, Silver, and Alloys of These from Electrolytes-Colloids: Fundamental Aspects, and Technological, Resourcesaving, and Ecological Solutions, Doctoral Dissertation, Novocherkassk, 2004. Kudryavtseva, I.D., Kukoz, F.I., and Balakai, V.I., Itogi Nauki Tekhniki VINITI, Moscow: Elektrokhimiya, 1990, vol. 33, pp. 50–85.
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