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Information × Registration Number 0306U001549, 0104U000653 , R & D reports Title Enviromental hrotection and rational use of nature resources of Ukraine (on the example of machine bulding and instruments construction plants) popup.stage_title Удосконалення процесів електрохімічного травлення металів Head Larin Vasilii Ivanovich, Registration Date 20-04-2006 Organization Kharkov national university named after V.N. Karazin popup.description2 The aim of the work - investigation of kinetic parameters and mechanism of copper-zinc alloys (brass) etching as well as of precipitates that form on copper and its alloys surface by chemical and electrochemical dissolving.The processes of brass dissolving in acidic solutions and electrochemical dissolving of Cu-Zn alloys in concentrated solutions of FeCl3, CuCl2 and their mixtures as well as in chloride-contained acetonitrile and acetonitrile-water mixtures have been studied with the use of the methods of revolving disc electrode, radiometry, pulsed potentiostatic method, electronic оj-spectroscopy, X-ray analysis etc. Surface compounds formed by these processes have been identified. The process of electrochemical dissolving of copper and its copper-zinc alloy L 68 in solutions of chemical polishing with composition Н2О2 + Н2SO4 + С2Н5ОН has been studied. The compounds as Cu2O, CuO, Cu(OH)2 have been found to be form on the surface. The thickness of the layers on copper and brass surface at different withstanding time has been experimentally determined. Firstly Cu(OH)2, the CuO have been shown to be reduct by cathodic reduction in standard et tetraborate buffer solution. Kinetics of anodic dissolving of Cu-Zn ?-alloys in stationary regime has been experimentally investigated and analysed. Selective zinc dissolving in acidic chlorid-contained solutions that accompanied by zinc atoms diffusion from alloy bulk to the alloy/solution border. The psevdoselektiv dissolving of alloy take place with Cu+ - ions accumulation in solution i.e. reverse precipitation of copper crystals on alloy surface.By pulsed potentiostatic method is shown, that on early stage the dissolving passes in the condition of mixed kinetics, alter 0,2 sek. the process of selective zinc dissolving is limited by non-stationary diffusion into alloy bulk. The diffusion coefficient of Zn atoms in brass has been found to be reduce in njn-stationary regime of selective dissolving because of decrease of non-equilibrium vacancies concentration in alloy surface layer.Brass dissolving in chloride-contained water-acetonitrile mixtures has been shown to be limited by cathodic stage of the process. The concentration areas of non-aqueous component, in which the main processes are zinc-out and regular alley dissolving, have been establisheol. The nature of in habiting compounds is determined for aqueous they are CuCl, CuOH and Zn for water-organic ones also - Cu(OH)2 and Zn(OH)2/ Product Description popup.authors popup.nrat_date 2020-04-02 Close