Shestakov I.Ya., Voroshilova M.V., Voroshilov D.S. Looking at the surface quality during local ammonium nitrate electrolytic machining

Abstract

This article describes the results of the research into electrolytic machining of 1201 aluminium alloy in aqueous solutions of ammonium nitrate. Having analysed some of Russian and international research papers on electrolytic machining, the authors came to the conclusion that studying the shape of an EDM tool (including its simulation) presents an important problem. A variety of factors determine the shape of an EDM tool, such as the electrolyte flow rate, the electrolyte temperature, the current density. The electrode coating is also important as it helps improve the quality of machining. The research conducted helped determine the effect of the electrolyte composition, current density and flow rate on the surface quality along the anode-to-cathode distance. The experiments showed that the flow rate of ~0.55 m/s provides the minimum roughness and the excessive flow rate largely affects the surface quality. It was found that the use of a circular cross-section cathode tool leads to the current spreading across the surface of the workpiece which reduces the machining accuracy and surface roughness in the transition zone. The use of a cathode with a flat face helps localize the current density on the treated surface thus increasing the machining accuracy. It was established that a cathode tool with a titanium oxide flat face helps reduce the surface roughness. The research helped identify the best electrolytic machining technique for large thin-walled parts when using a titanium cathode tool with a semiconductor coating. Below are the recommended electrolytic machining parameters: current density between 14 and 26 A/cm2, flow rate between 0.3 and 0.6 m/s, electrolyte temperature 25 – 30°C. The following aqueous solution is recommended for electrolyte: 15% NH4NO3 + 2,5% Na3C6H5O7.

Keywords

Electrolytic machining, EDM tool, cathode, roughness, electrolyte, flow rate, current density.

Ivan Ya. Shestakov – D.Sc. (Eng.), Professor

Siberian Federal University, Krasnoyarsk, Russia. Phone: +7 (391) 206-37-78. Е-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Marina V. Voroshilova – Assistant Professor

Siberian Federal University, Krasnoyarsk, Russia. Phone: +7 (391) 206-36-18. Е-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Denis S. Voroshilov – Ph.D. (Eng.), Associate Professor

Siberian Federal University, Krasnoyarsk, Russia. Phone: +7 (391) 206-37-31. Е-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

1. Amitan G.L., Baysupov I.A., Baron Yu.M. et al. Spravochnik po electrokhimicheskim i electrophizicheskim metodam obrabotki. [Handbook of electrochemical and electrophysical machining techniques]. Leningrad, 1988, 719 p. (In Russ.)

2. Smolentsev V.P., Boldyrev A.I., Smolentsev E.V. Teoriya electrokhimicheskih i fiziko-khimicheskhih metodov obrabotki [The theory of electrochemical and chemo-physical machining techniques]. Voronezh: Voronezh State Technical University, 2007. 376 p. (In Russ.)

3. Chang C.S., Hourng L.W. Two-dimensional two-phase numerical model for tool design in electrochemical machining. Journal of Applied Electrochemistry. Vol.31, iss. 2, 2001, pp. 145–154.

4. Zhou Y., Derby J.J. The cathode design problem in electrochemical machining. Chemical Engineering Science. Vol. 50, iss. 17, September 1995, pp. 2679–2689.

5. Jain V.K. Tooling design for ECM. Precision Engineering. Vol. 2, iss. 4, October 1980, pp. 195–206.

6. Reddy M.S., Jain V.K., Lal G.K. Tool design for ECM: Correction factor method. Journal of engineering for industry. Vol. 110, iss. 2, May 1988, pp. 111–118.

7. Chang C.S., Hourng L.W., Chung C.T. Tool design in electrochemical machining considering the effect of thermal-fluid properties. Journal of Applied Electrochemistry. Vol. 29, iss. 3, March 1999, pp. 321–330.

8. Purcar M., Bortels L., Van Den Bossche B., Deconinck J. 3D electrochemical machining computer simulations. Journal of Materials Processing Technology. Vol. 149, iss. 1-3, 10 June 2004, pp. 472–478.

9. S.M. A. Shibli, V.S. Dilimon, V.S. Saji. RuO2–TiO2 mixed oxide composite coating for improvement of Al-alloy sacrificial anodes. Journal of Solid State Electrochemistry. 2007, Vol. 11, iss. 2, pp. 201–208. doi: 10.1007/s10008-005-0088-5.

10. P. Shrivastava, Michael S. Moats. Wet film application techniques and their effects on the stability of RuO2–TiO2 coated titanium anodes. Journal of Applied Electrochemistry. 2009, Vol. 39, iss. 1, pp. 107–116. doi: 10.1007/s10800-008-9643-y.

11. V.V. Gorodetskii, V.A. Neburchilov, V.I. Alyab’eva. Titanium anodes with an active coating based on iridium oxides: the effect of the coating’s thickness, porosity, and morphology on its stability, selectivity, and catalytic activity. Russian Journal of Electrochemistry. 2005, vol. 41, no. 10, pp. 1111–1117.

12. Y. Wang, Y. Liao, W. Li, X. Tang, X. Li. Carbon coating of Li4Ti5O12-TiO2 anode by using cetyl trimethyl ammonium bromide as dispersant and phenolic resin as carbon precursor. Ionics. 2015, vol. 21, iss. 6, pp. 1539–1544. doi: 10.1007/s11581-014-1309-7.

13. B.Z. Nikolic, V.V. Panic, A.B. Dekanski. Intrinsic potential-dependent performances of a sol–gel-prepared electrocatalytic IrO2–TiO2 coating of dimensionally stable anodes. Electrocatalysis. 2012, vol. 3, iss. 3, pp. 360–368. doi: 10.1007/s12678-012-0086-1.

14. V.V. Gorodetskii, V.A. Neburchilov. Titanium anodes with active coatings based on iridium oxides: the chemical composition of the coatings and the distribution of their components over depth on anodes made of IrO2, IrO2 + TiO2, IrO2 + RuO2 + TiO2, and IrO2 + RuO2 + TiO2 + Ta2O5. Russian Journal of Electrochemistry. Vol. 39, no. 10, 2003, pp. 1116–1123.

15. V.V. Gorodetskii, V.A. Neburchilov. Tantalum Oxide Effect on the Surface Structure and Morphology of the IrO2 and IrO2 + RuO2 + TiO2 Coatings and on the Corrosion and Electrochemical Properties of Anodes Prepared from These. Russian Journal of Electrochemistry. 2007, vol. 43, no. 2, pp. 223–228.

16. F. Moradi, C. Dehghanian. Influence of heat treatment temperature on the electrochemical properties and corrosion behavior of RuO2–TiO2 coating in acidic chloride solution. Protection of Metals and Physical Chemistry of Surfaces, 2013, vol. 49, no. 6, pp. 699–704. doi: 10.1134/S2070205113060245.

17. W. Dengyong, Z. Zengwei, W. Ningfeng, Z. Di. Effects of shielding coatings on the anode shaping process during counter-rotating electrochemical machining. Chinise journal of mechanical engineering. 2016, vol. 29, no. 5, pp. 971–976. doi: 10.3901/CJME.2016.0419.055.

18. D.E. Lee, S.A. Soper, W. Wang. Fabrication and mathematical analysis of an electrochemical microactuator (ECM) using electrodes coated with platinum nano-particles. Microsystem Technologies. 2010, vol. 16, iss. 3, pp. 381–390. doi: 10.1007/s00542-009-0940-0.

19. D. Wang, Z. Zhu, J. Bao, D. Zhu. Reduction of stray corrosion by using iron coating in NaNO3 solution during electrochemical machining. The International Journal of Advanced Manufacturing Technology. 2015, vol. 76, iss. 5, pp. 1365–1370. doi: 10.1007/s00170-014-6351-0.

20. Samsonov G.V., Borisova A.L. et al. Fiziko-khimicheskhie svoistva okislov. Spravochnik [The physical and chemical properties of oxides. Handbook]. Moscow: Metallurgiya, 1978. 472 p. (In Russ.)

Details: Published: 28 March 2017; Last Updated: 28 March 2017; Hits: 2917