The aim of the study. By introducing strong oxidizers to the electrolyte form anode layers on the surface of aluminum with increased mechanical characteristics. To determine the effect of the duration of the formation of an anode layer to change its properties. Hard anodizing was performed at a temperature of –4...0C for 60 min. A 20% aqueous solution of H2SO4 was used as the base electrolyte. During anodizing, the current density was 5 A/dm2. To determine the effect of strong oxidants on the characteristics of the anode layers (oxide), 30 were added to the electrolyte; 50; 70 and 100 г/лof hydrogen peroxide (H2O2). In some cases, it was purged with an ozone-air mixture at a rate of 5 mgmin/l of ozone. It was found that the oxide layer (Al2O3H2O) during hard anodizing on aluminium alloys forms not only oxygen ions, which are formed by the decomposition of water, but also neutral oxygen atoms, which are formed by the decomposition of hydrogen peroxide and ozone. It was found that hydrogen peroxide, as well as blowing the electrolyte with an air-ozone mixture increase the thickness and microhardness of the anodized layer by 50% due to the reduction of the number of water molecules in alumina by half. Hydrogen peroxide and ozone apparently also reduce the thickness of the barrier layer of the coating, through which oxygen and aluminium ions penetrate and which, when combined, form an oxide layer. Conclusions. 1. It has been established that aluminum anodizing for 60 minutes. provides an increase in its properties. Changing the composition of the electrolyte contributes to the growth of microhardness in 1.2 ... 1.7 times. The resistance of abrasive wear increases with the content of different amounts of applications in the electrolyte and the maximum is at 30 g / l H2O2. Blowing the base electrolyte ozone provides an increase in the microhardness of the layer from 380 to 510 HV. The higher loss of mass for higher microhardness is caused by an increase in porosity of coatings. 2. It is determined that an increase in the anodization time in the baseline electrolyte to 120 and 180 minutes contributes to the growth of microhardness to 640 HV compared to an anodized layer for 60 minutes. Loss of mass in the study of abrasive wear is less than 3-4 times with longer anodation than at 60 minutes in the baseline electrolyte.

solid anodizing, aluminum, oxide and barrier layers, pores, microhardness

Full Text:

PDF

1. Student, М. М. et al. (2017). Friction behavior of iron-carbon alloys in couples with plasma-electrolytic oxide-ceramic layers synthesized on D16T alloy. Materials Science. 53, № 2. P. 359–367 [in English].

2. Posuvailo, V. M. et al. (2017). Gibbs energy calculation of electrolytic plasma channel with inclusions of copper and copper oxide with Al-base. Mat. Sci. and Eng. 181, № 1. P. 157–168 [in English].

3. Hutsaylyuk, V. et al. (2019). Effect of hydrogen on the wear resistance of steels upon contact with plasma electrolytic oxi¬dation layers synthesized on aluminium alloys . Metals. 9, № 3. Р. 280. https://doi.org/10.3390/met9030280 [in English].

4. Pokhmurs’ka, V. et al. (2005). Structure and properties of aluminum alloys modified with silicon carbide by laser surface treatment . Materials Science. 41, № 3. Р. 316–323 [in English].

5. Stupnyts’kyi, T. R. et al. (2016). Optimization of the chromium content of powder wires of the Fe–Cr–C and Fe–Cr–B sys¬tems according to the corrosion resistance of electric-arc coatings . Materials Science. 52, № 2. Р. 165–172 [in English].

6. Golovin, Ju. I. (1991). Nanoindentirovanie i ego vozmozhnosti [Nanoindentation and its capabilities]. Moskow: Metallurgija.[in Russian].

7. Torrescano Alvarez & Jeanette Marcela. (2018). Hard anodic films for aluminium alloys. The University of Manchester, UK [in English].

8. Ning-ning Hu, Shi-rong Ge & Liang Fang. (2011). Tribological properties of nano-porous anodic aluminum oxide template . J. of Central South University of Tech. 18. Р. 1004−1008 [in English].

9. Alaa M. Abd-Elnaiem & Gaber A. (2013). Parametric study on the anodization of fabricating nano-pores template . Int. J. Electrochem. Sci. 13. P. 9741–9751 [in English].

10. Galusek D. & Ghillányová K. (2010). Ceramic oxides. Ceramics Science and Technology. Mat. and Properties. Darmstadt: Wiley-VCH. 2, Ch. 1. P. 3–58 [in English].

Copyright (c) 2021 Mykhajlo Student, Volodymyr Hvozdetskii, Halyna Veselivska, Khrystyna Zadorozhna, Roman Mardarevych, Yaruna Sirak