Autocatality effect of AlCl3 applications on the oxidation process of amorphous Al87Ni8Y5 alloy in 0.5 M aqueous NaCl solution

Abstract

Investigation of corrosion resistance of amorphous metal alloy ( AMA ) from aluminum is carried out in 0.5 M aqueous solutions of NaCl. Cl- ions penetrate the oxide layer through pores or defects and can colloidally disperse the oxide film and increase its permeability . The Al 87 Ni 8 Y 5 were obtained by melt spinning technique in helium atmosphere onto a copper wheel with a circumferential speed of about 30 m/sec (cooling rate = 10 6 К/sec). The method of voltammetry in the potential-dynamic mode showed that the introduction of AlCl 3 (7.4·10 -3 mol/l) in the system of origin reduces the first maximum, which is responsible for the adsorption of Н + on the AMА electrode. A potentiostatic ivestigates of the behavior of Al 87 Ni 8 Y 5 in 0.5 M aqueous NaCl solution with additional elements AlCl 3 indicates the autocatalytic properties of a low concentration of AlCl 3 (2·10 -7 mol/l), which contributes to the dissolution of the surface. The kinetics of establishing the stationary potential in 0.5 M aqueous NaCl solution and with AlCl 3 applications were chronopotentiometrically investigated. The presence of AlCl 3 ions in the background electrolyte during chronopotentiometry of AMA Al 87 Ni 8 Y 5 in 0.5 M aqueous sodium chloride solution reduces the position of the potential dependence. To independently confirm the influence of Al 3+ and Cl - ions on the processes of formation of protective layers on the surface of Al 87 Ni 8 Y 5 in 0.5 M aqueous NaCl solution using a electron microscope. Micrographs of the alloy surface were taken after VA removal in NaCl background solution 1M application of AlCl 3 , the surface of the alloy in NaCl solution is covered with a thin layer of oxides and hydroxides of aluminum, and due to the sweep potentials in the range of -1000 ÷ +300 mV in the presence of AlCl 3 a multilayer coating is formed. Keywords: amorphous metallic alloys, passivation layers, corrosion resistance.