ISSN 1070-4272, Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 9, pp. 1317−1325. © Pleiades Publishing, Ltd., 2013. Original Russian Text © A.A. Ivanov, V.V. Botvin, A.G. Filimoshkin, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 9, pp. 1345−1353.
INORGANIC SYNTHESIS AND INDUSTRIAL INORGANIC CHEMISTRY
A New Technology for Forming Highly Developed Aluminum Surface by Electric Pulse Ablation A. A. Ivanov, V. V. Botvin, and A. G. Filimoshkin National Research Tomsk State University, Tomsk, Russia e-mail:
[email protected] Received July 30, 2013
Abstract—A novel polymeric composite whose conducting domains in the course of electric pulse treatment transfer onto an aluminum surface the microrelief information in the form of roughness was suggested. The degree of roughness is larger than 9.0 μm, exceeding by a factor of approximately 200 the aluminum surface roughness before ablation (Ra = 9.42 μm, roughness coefficient K = 16.69, profile height along the base length from 5 to 70 μm). Analysis of 3D scans and profilograms of the aluminum plate surface after the ablation allows choice of methodological and technological approaches to the formation of the developed surface topology by this procedure. DOI: 10.1134/S1070427213090011
Preparation of multilayer coatings for various purposes, e.g., in electronic industry and LED technology, requires the development of a modern technology for treating smooth metal surfaces, namely, for creating a rough surface or a relief structure, a pattern, or a certain image [1, 2]. A certain analog of such process is photolithography, when the phototemplate image is transferred as a relief pattern onto a silicon surface. In some cases, the most convenient way to create roughness is electroerosion treatment. At the same time, creation of a rough surface and subsequent application of coatings onto it involve fundamental problems concerning the physical chemistry of the surface, in particular, adhesion. For example, filled polyaluminosilicates are applied as a dielectric layer onto the surface of aluminum items with a high degree of roughness. These coatings facilitate the dissipation of heat released in the operating microelectronic and LED devices [3]. There is no need to speak of the role of microelectronics in the economy of any state. Particular attention is given today to the development of electronic and LED industry in Russia. However, significant progress in these branches will be possible only if new materials, processes, and structures capable to replace imported ones will be developed and introduced into practice. That is one of the main goals of the Russian innovation strategy.
This study is the first in a series of studies concerning formation of multilayer coatings. Its aim consists in the development of a novel conducting polymeric composite (CPC) as a working electrode with agglomerates of silver particles of different heights and cross sections, arranged in the polymeric matrix, as conducting paths, and also in the development of electric pulse ablation procedure using this CPC as cathode. The development of the new technology is based on the assumption that the electric pulse treatment involves peculiar transfer of the information on the microrelief of the conducting paths of the CPC cathode in the 3D format onto the surface of an aluminum item acting as anode (in our experiments, onto an aluminum plate). The relief pattern of definite configuration is “recorded” on the plate surface as roughness of high degree. Working electrodes in the form of CPC with the surface microrelief design bearing a certain idea can be used for special electroerosion ablation of metal items.
1317
CONDUCTING POLYMERIC COMPOSITE BASED ON SILVER NANO- AND MICROPARTICLES AS WORKING ELECTRODE FOR ABLATION Electroerosion (in particular, electric pulse) ablation
1318
IVANOV et al.
of a surface consists in affecting the surface, primarily the metal surface, with electric plasma. An arc discharge is ignited between the electrodes. The high-energy ion flux generated in the process interacts with the surface being treated [4, 5]. This ionic plasma flux causes fusion, sublimation, and detachment of metal particles with the formation of overlapping craters of different diameters and depths on the surface (so-called roughness). Thus, one of the electrodes is the working electrode, and the other electrode is a smooth surface becoming rough and developed. Below we report the results of the development and fabrication of CPC as a novel working electrode. The formulation is applied onto a metal support in the form of a layer of definite thickness. This layer is actually an agglomeration of an enormous number of conducting paths, “incorporated” in the copolymer matrix, with protrusions of various heights forming a certain design or relief pattern. Conducting polymeric composite as a working electrode. To obtain craters of different sizes on the surface of an item serving as electrode, it is necessary to form a large number of protrusions of different heights providing different interelectrode distances (i.e., discharge sites) over the whole surface of the working electrode. To solve this problem, we chose the design of the working electrode consisting of a polymeric matrix and a mixture of silver nano- and microparticles (about 80 wt %) as agglomerates, forming the so-called CPC. As a polymeric matrix of CPC of the working electrodes, we used copolymers of maleic anhydride with vinyl chloride (VC–MA) and vinyl acetate (VA–МА). The flexibility of their macromolecules is sufficient and can be controlled by varying the solvent (dioxane, THF, acetone, DMF, alcohols, water, etc.):
At the same time, a unique property of MA copolymers is the capability of certain adjacent succinic anhydride and vinyl chloride, or succining anhydride and vinyl acetate (m-an) units, forming the backbone of the copolymer macromolecules, for tautomerism with the formation of enol (Δ6-en) derivatives of furan [6–9], increasing both the flexibility of macromolecules and their affinity for the silver and aluminum surfaces, as illustrated below by the example of VC–MA:
Maleic anhydride copolymers exhibit good filmforming properties and high adhesion to metals. The presence of polar Δ6-en units favors fixation of agglomerates of silver nano- and microparticles in microvoids of the CPC matrix. Clusters of silver particles form protrusions of different heights on conducting paths. Specifically these protrusions of different heights provide different interelectrode spacings in the course of electroerosion treatment. In a series of electric discharges, this leads to ablation with the formation of craters of different depths on the surface of the item being treated. In other words, the protrusions of conducting paths, forming the specific CPC morphology, favor the development of high roughness on an aluminum item. With the aim to find conditions for controlling the CPC morphology, we first estimated the flexibility and shape of macromolecules forming ordered domains in the course of formation of a polymer layer on a plate and participating in the formation of interdomain voids in which the silver particles are accommodated. The estimation was based on the results of computer simulation and of viscometric measurements of VC–MA solutions in solvents differing in the chemical nature. Quantum-chemical calculations of distances between the ends of VC–MA macromolecules under the conditions of full desolvation (vacuum) were performed with GAUSSIAN98 program package [10–12]. Figure 1 schematically shows the visualized model of VC–MA macromolecule and its projection onto a plane with the rms distance between the termini
1/2, which was calculated by the Flory–Fox equation from the results of experimental studies [13], Ф1/2 = [η]М,
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 9 2013
A NEW TECHNOLOGY FOR FORMING HIGHLY DEVELOPED ALUMINUM SURFACE Experimental values of [η] and 1/2 of solutions of VC–MA copolymer Solvent THF
[η], dl g–1
1/2 × 107, m
0.401
0.770
Dioxane-1,4
0.262
0.668
DMSO
0.174
0.576
DMF
0.132
0.527
Acetone
0.101
0.485
Ethyl acetate
0.036
0.344
from two quantities, intrinsic viscosity [η] and molecular weight М [Ф = 2.84 × 1021 mol–1, c (g dl–1), swelling coefficient α = 1], for five solvents in which [η] was measured. The distance between the ends of macromolecules, calculated by computer simulation, is h2 × 107 = 1.053 m. The experimental values of the rms distance 1/2 are given in the table. The VC–MA macromolecules are the most
1319
straightened in THF, in which 1/2 = 0.770 m, whereas dense coils are formed in ethyl acetate, in which 1/2 = 0.344 m. It is interesting that the distance between the termini of unsolvated macromolecules, calculated by computer simulation in a vacuum, appeared to be almost 30% longer than 1/2 measured in THF and 3 times longer than 1/2 measured in ethyl acetate. Thus, the possibility of controlling the shape of macromolecules and, ultimately, the CPC morphology by choosing appropriate solvent suggests the possibility of predicting the “design” of supramolecular structures (domains) by a simple and available method and of controlling the geometry of interdomain voids which are filled with silver nano- and microparticles, thus becoming conducting paths of the working electrode. At the same time, correlation of the quantum-chemically calculated (GAUSSIAN 98) distances between the ends of macromolecules with the corresponding experimental quantities (determined, e.g., by viscometry) allows us also to look forward with optimism at the possibility (a)
1 mm (b)
0.1 mm Fig. 1. A model of a VC–MA macromolecule with the degree of polymerization of 600 (image constructed with GAUSSIAN 98 program package) and its 2D projection onto a plane.
Fig. 2. Photomicrographs of VC–MA films cast from THF and ethyl acetate (to the right). Magnification ×480.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 9 2013
1320
IVANOV et al.
of a priori choosing the polymers and controlling the morphology of conducting paths in CPC without laborand time-consuming empirical search. For visual check of the possibility of such control with solvents, we examined the films of straight VC–MA copolymer, cast from THF and ethyl acetate, on an MBI15 microscope (Fig. 2). These solvents were chosen as having close boiling points (66 and 77°С, respectively), but different affinities for VC–MA copolymer. In THF, the macromolecules form deformed rods, whereas in ethyl acetate they form coils (see table). Figure 2 clearly shows that, other conditions being equal, lengthy supramolecular structures are formed in the films cast from THF but are not formed in the films cast from ethyl acetate. In other words, the largest interdomain voids for accommodation of silver particles should be formed in systems in which the macromolecules are straightened to maximum extent. Another problem in the formation of CPC morphology is estimating the geometry of conducting paths of silver particles arranged in interdomain voids. It should be noted that here the tools for controlling the morphology are even more diverse. Along with the thermodynamic approach (variation of the solvent, copolymer concentration, and temperature), efficient nonthermodynamic methods appear here, e.g., variation of the centrifugation rate in application of CPC films or layers. For example, in the course of centrifugation of a suspension of silver nanoand microparticles in a solution of VC–MA copolymer (a)
in THF, the solvent is gradually evaporated. In the process, controlled by the rotation rate, the macromolecules approach each other, the intermolecular interactions of units increase, and copolymer macromolecules form supramolecular structures (domains) with dense packing of macromolecules. The domains having dielectric properties are separated from each other by loose regions with randomly arranged tie chains and ends of macromolecules, forming so-called microvoids. Figure 3 shows the micrographs of CPC specimens, taken by high-resolution electron microscopy in secondary electron field emission mode with an SMA Quanta 3D FEG dual-beam scanning electron–ion microscope (the accelerating voltage and scale are indicated in the images). Specifically the microvoids are filled with silver nano- and microparticles, which undergo densification under the action of centrifugal forces and with solvent evaporation, forming continuous conducting paths. It is interesting that the geometry and size of both domains and interdomain voids can be diverse and even intricate [14]. Such possibilities of macromolecular systems can be used for the development of a method for forming the roughness design that copies the CPC morphology as relief image of microvoids intended for filling with nanosilver, i.e., a design that reproduces, at least approximately, the geometry and size of interdomain regions. This approach can be used for the development of a new method of transferring information on the geometry and size of in(b)
160.0 nm
.4 48
2
nm
m
830.6 n
.4 34
nm
1
Fig. 3. Photomicrograph of the surface of the conducting composite applied onto the surface of an aluminum support by centrifugation. RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 9 2013
A NEW TECHNOLOGY FOR FORMING HIGHLY DEVELOPED ALUMINUM SURFACE
terdomain voids in the form of roughness as a relief image (prototype) of conducting paths consisting of protrusions and cavities of various heights and depths. There are good grounds to term the new method electroerosiographic, by analogy with the photolithographic method. However, the latter method reproduces the phototemplate pattern very accurately in the form of relief images of components of a future integrated microcircuit. Below we describe our first experience on the transfer of information on interdomain voids of CPC in the form of a relief under the conditions of electric pulse treatment.
1321
Fig. 4. Surface roughness profile and designations of its characteristics.
FORMATION OF A ROUGH SURFACE OF AN ALUMINUM PLATE USING A CONDUCTING POLYMERIC COMPOSITE Treatment of smooth surfaces with the aim to increase their surface area, followed by application of special coatings, is a rapidly developing field of composite materials science. The surface area is increased by making the surface rough, i.e., by creating a complex of protrusions and cavities on the surface using various kinds of surface treatment. This allows enhancement of the corrosion resistance, strength, wear resistance, and adhesion of the new layer to the treated surface, and also improvement of decorative and other consumer’s properties. The surface roughness as a set of small-scale unevenness elements is formed by affecting the surface using various procedures. However, not all the methods are suitable for controllable removal (ablation) of a definite amount of the material from the surface of an item being treated [1, 2]. Electric pulse treatment of flat aluminum plate as anode. Any solid surface is a complex of protrusions and cavities (Fig. 4) described by a set of certain roughness parameters, the main of which is the arithmetic mean deviation of the surface profile, or the degree of roughness Ra:
In other words, Ra is the arithmetic mean deviation of the profile yi from the mean line m within the limits of the base length (Fig. 4) [3]. The visual (experimental) pattern of the surface topology, schematically shown in Fig. 4, is presented in the Profilometry section in the form of high-resolution 3D micrographs. The surface was scanned
220 V
Fig. 5. Scheme of an installation for electroerosion ablation of the Al support: (1) working CPC electrode, (2) Al support being modified, (3) electrolyte solution, (4) stainless steel bath, and (5) power source. The surface treatment (ablation) can be performed in two modes: electric spark (1р) or electric pulse (2р).
using optical sensors on a precision device. Both smooth and rough surfaces are used in industrial processes. Rough surfaces are treated, e.g., by sandblasting [15], wet chemical etching [16], and plasma chemical [17] and electroerosion [5] methods. In many cases, electroerosion ablation is the most convenient method. It ensures the required degree of roughness characterized by the roughness coefficient K: K = Sr/Sо, where Sr and Sо are the areas of the rough and ideally smooth surfaces, respectively. To create a relief pattern (roughness) as a system of overlapping craters, an aluminum plate was subjected to electric pulse treatment at the voltage U = 1000 V and pulse length of 500 μs using a specially fabricated novel working electrode with CPC as cathode (Fig. 5). In the general form, the procedure for making the surface rough by electroerosion ablation is as follows. An arc discharge is ignited between electrodes 1 and 2
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 9 2013
1322
IVANOV et al. (a)
20 μm (b) 72.4 μm
0.5 μm
0.5
μm
(c) 84.7 μm
0.5 μm
(Fig. 5). As a result, high-energy ion flux is generated. It interacts with the surface of plate 2 being treated [3, 5]. The dielectric polymer serving as polymeric matrix of CPC undergoes pyrolysis at the boundary of plasma discharge channels contacting with electrode areas heated to high temperatures. As a result of the flow of gases generated by the polymer pyrolysis, microparticles of the molten metal are ejected beyond the working zone, leaving overlapping craters. The set of protrusions and craters on the surface forms a relief image in the form of a picturesque “landscape,” a set of unevenness elements of different heights and depths, i.e., the roughness (Fig. 3). This relief image is formed by ablation of the aluminum surface, resulting from the fact that protrusions of different heights on conducting paths of the working electrode provide different interelectrode spacings. In the course of a series of electric discharges, this leads to electroerosion of the surface, accompanied by the formation of a specific set of unevenness elements of different depths on the surface. In other words, protrusions of the conducting paths, forming a specific CPC morphology, favor creation of a high degree of roughness on an aluminum item. After the end of each discharge, the channel cools within a certain time, the plasma in the interelectrode space undergoes deionization, and the electric strength of the material is restored. The next discharge usually arises in another place, between two other nearest points of the electrodes. To remove from the discharge zone electroerosion products and gas microbubbles, which are the main obstacle to generation of the next discharge, there should be adequate intervals between the pulses. Therefore, the discharge frequency decreases with a simultaneous increase in the discharge energy. This trend is kept until the discharges remove from the electrode surface all the metal occurring at the breakdown distance at the given voltage [3, 5]. The main parameters of electric pulses fed to the interelectrode space are the pulse length, amplitude, repetition frequency, and the created porosity (sponginess, cellular structure, pores) and its configuration [5]. The morphology of conducting paths together with the pulse shape and parameters exerts a decisive effect on the support roughness. The electrophysical pattern of the origination, development, and decay of discharges suggests that it is difficult to make an accurate copy of the CPC conducting paths in the form of a rough design, but
0.5
μm
Fig. 6. (a) 2D and (b, c) two 3D scans of an aluminum plate, taken from different sites on the plate surface subjected to electric pulse ablation.
it is possible to obtain a relief image of CPC, or a preset design. Furthermore, protrusions of conducting channels of the working electrodes allow the crater depth to be increased (“drilling” of the plate). The profile and depth of craters were estimated by
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 9 2013
A NEW TECHNOLOGY FOR FORMING HIGHLY DEVELOPED ALUMINUM SURFACE
1323
Fig. 7. Element distribution spectrum of CPC used for creating roughness on the Al plate surface. (I) Intensity.
profilometry of the rough surface of the aluminum plate (Fig. 6), formed as described above using the novel working electrode. Profilometry of the plate subjected to electric pulse ablation. The topological pattern of the aluminum plate (Fig. 6) subjected to electric pulse treatment of the surface using a specially prepared CPC was obtained with an MM3D Station device with computer analysis of the topology and of the shape and size of relief components. Figure 6 shows (with indication of the size of the new formations) the topological pattern in the form of twoand three-dimensional scans of the surface. These images demonstrate superdeveloped surface of the aluminum plate subjected to ablation with the CPC electrode. The main parameters of the roughness were determined from the profilogram of an arbitrarily chosen area on the plate surface [18]. The aluminum surface formed has the degree of roughness Ra = 9.42 μm and profile height along the base length from 5 to 70 μm; K = 16.69 (So = 2500 μm2, Sr = 29 841 + 11 886 = 41 727 μm2). It is interesting that some roughness parameters (depth of craters and height of protrusions in some areas of the surface) correlate with the size of protrusions on bunches of silver particles, formed in conducting paths of the CPC cathode. Thus, comparison of the profilograms and CPC relieves as negative and positive images allows adjustment of the conditions for the formation of the CPC morphology for purposeful construction of a configuration of silver nano- and microparticle agglomerates in conducting paths of the working electrode.
EXPERIMENTAL Polymeric matrix. Samples of VC–MA copolymer were prepared by heating the monomers (1 : 1 ratio) in 1,2-dichloroethane in the presence of benzoyl peroxide (1 wt %) in sealed ampules at 80°С for 24 h. The ratio of the monomeric units is 1 (VC) : 1.01 (succinic anhydride); Мw = 109 000, Мn = 100 000, yield 80%, degree of polymerization n ≈ 600. The isolation, purification, and identification are described in detail in [19]. GAUSSIAN 98 program complex [10–12] was used for estimation of the distance between the chain ends and for computer imaging of the copolymer macromolecules without solvation (in a vacuum). Viscometric measurements were performed by the standard procedure at 25 ± 0.1°С in an Ubbelohde viscometer with suspended level. Conducting polymeric composite. A uniform suspension was prepared by the standard procedure of ultrasonic dispersion of a mixture of silver nano- and microparticles (80 wt % relative to VC–MA) in a 10 wt % solution of VC–MA copolymer in THF, after which it was transferred onto aluminum supports fixed in a centrifuge. The results of microanalysis of CPC prepared for ablation are shown in Fig. 7. To obtain CPC layers of required thickness, the freshly prepared suspension was applied onto Al supports by successive centrifugation (three to six portions). To fully remove the residual solvent from the ready coatings, they were kept in a vacuum at room temperature for 3 h. The electric pulse treatment of an aluminum plate serving as anode was performed at the voltage U = 1000 V and pulse length of 500 μs (Fig. 5). The bath was
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 9 2013
1324
IVANOV et al.
filled with an electrolyte containing NaF, H3BO3, borax, Na2HPO4, and water [20]. The profilograms were recorded with a Micro Measure 3D Station high-precision measurement installation (STIL, France) allowing high-resolution 3D photomicrographs to be obtained, with analysis of the unevenness shapes and texture by the contactless method using optical sensors. The measured geometric quantities transform into profiles and topologies of the surface (Fig. 6). The installation is equipped with a digital video camera. CONCLUSIONS
heat-conducting polyaluminosilicate layers onto a rough aluminum surface. ACKNOWLEDGMENTS The study was financially supported by the Foundation for Implementation of the Project “ LTCC Technology for Preparing Multilayer Ceramic Printed-Circuit Boards” (State Contract no. 8169r/12641) and by State Contract of June 28, 2013, of the program “Participant of Research and Innovation Competition of Young People.” REFERENCES
(1) A novel conducting polymeric composite (CPC) of definite morphology, based on silver nano- and microparticles accommodated in interdomain voids of the amorphous layer of vinyl chloride–maleic anhydride copolymer was developed. The morphology can be controlled by varying the solvent. (2) Within the aim to develop methods for controlling the morphology of the conducting polymeric composite, the flexibility and shape of vinyl chloride–maleic anhydride macromolecules were estimated both by computer simulation and by viscometric studies of vinyl chloride–maleic anhydride copoolymer solutions. The correlation between the calculated (GAUSSIAN 98) and experimentally measured shapes of the macromolecules gives grounds to hope that it will be possible to choose polymers a priori for modeling the morphology or “design” of domains and interdomain voids for creation of conducting paths. (3) An approach was suggested to arrangement of silver nano- and microparticles in interdomain voids acting as conducting paths of the working cathode in the course of electroerosion ablation of aluminum. (4) The conditions of electric pulse ablation of aluminum using a conducting polymeric composite, allowing the aluminum surface roughness to be increased by a factor of almost 200, were found. (5) The 3D scans and high-precision profilograms of the aluminum plate surface treated by electric pulse ablation were obtained. Methodological and technological approaches to forming the required surface topology were developed. (6) The suggested method of aluminum ablation is a necessary process step prior to application of functional
1 Garkunov, D.N., Tribotekhnika (iznos i bezyznosnost’): Uchebnik (Friction Engineering) (Wear and Wearless Operation): Textbook), Moscow: Mosk. Sel’skokhoz. Akad., 2001, 4th ed. 2 Prikhod’ko, E.A., Belousova, N.S., Moreva, N.A., et al., Nauchn. Vestn. Novosibisrk. Gos. Tekh. Univ., 2010, no. 2 (39), pp. 145–156. 3 RF Patent 100352. 4. Foteev, N.K., Tekhnologiya elektroerozionnoi obrabotki (Technology of Electroerosion Treatment), Moscow: Mashinostroenie, 1980. 5. Nemilov, E.F., Elektroerozionnaya obrabotka materialov (Electroerosion Treatment of Materials), Leningrad: Mashinostroenie, 1983. 6. Filimoshkin, A.G., Chernov, E.B., Terent’eva, G.A., et al., Zh. Prikl. Khim., 2001, vol. 74, no. 2, pp. 292–299. 7. Filimoshkin, A.G., Kosolapova, V.F., Chernov, E.B., and Berezina, E.M., Eur. Polym. J., 2003, vol. 39, pp. 1461– 1466. 8. Pavlova, T.V., Terent’eva, G.A., Chernov, E.B., and Filimoshkin, A.G., Zh. Prikl. Khim., 1999, vol. 72, no. 9, pp. 1515–1517. 9. Filimoshkin, A., Berezina, E., Manzhay, V., et al., e-Polymers, 2011, no. 056, pp. 1–14, http://www.e-polymers.org 10. GAUSSIAN 98W. User’s Reference, Fritsch, E. and Fritsch, M. J., Eds., Pittsburgh, Gaussian, 1998, http://www.gaussian.com 11. Becke, A.D., J. Chem. Phys., 1993, vol. 98, pp. 5648–5652. 12. Parr, R.G. and Yang, W., Density-Functional Theory of Atom and Molecules, New York: Oxford Univ. Press, 1989. 13. Tager, A.A., Fizikokhimiya polimerov (Physical Chemistry of Polymers), Moscow: Nauchnyi Mir, 2007. 14. Slonimskii, G.L., Supramolecular Structure of Polymers,
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 9 2013
A NEW TECHNOLOGY FOR FORMING HIGHLY DEVELOPED ALUMINUM SURFACE Entsiklopediya polimerov (Polymer Encyclopedia), Kabanov, V.A., Ed., Moscow: Sov. Entsiklopediya, 1974, vol. 2, p. 320. 15. Kozlov, D.Yu., Blasting: Gid po vysokoeffektivnoi abrazivostruinoi ochiskte (Blasting: Guide on High-Efficiency Abrasive Blasting), Yekaterinburg: Origami, 2007. 16. Beckert, M. and Klemm, H., Handbuch der metallographischen Ätzverfahren, Leipzig: Grundstoffindustrie, 1976, 3rd ed. 17. Polak, L.S., Plazmokhimicheskie reaktsii i protsessy (Plasma Chemical Reactions and Processes), Moscow:
1325
Nauka, 1977. 18. GOST (State Standard) 2789–73, ISO 468:1982: Surface Roughness—Parameters, Their Values and General Rules for Specifying Requirements. 19. Filimoshkin, A.G., Terentieva, G.A., Berezina, E.M., et al., J. Polym. Sci., Part A: Polym. Chem., 1993, vol. 31, pp. 1911–1914. 20. Mamaev, A.I. and Mamaeva, V.A., Sil’notokovye protsessy v rastvorakh elektrolitov (High-Current Processes in Electrolyte Solutions), Novosibirsk: Sib. Otdel. Ross. Akad. Nauk, 2005.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 9 2013
