Page 9 - Korniy_dyser

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which altogether characterize corrosive damage depending on the environment and
surface atoms. This allows us to unravel the mechanisms of corrosion and explain

the efficiency of anti-corrosive protection (mainly by inhibitors) of metals when
the barrier layers on their surfaces are perturbed.

Next, using quantum-chemical calculations, we have determined the
interaction between the intermetallic phases of aluminum alloys Al 2Cu and

Al 2CuMg and corrosive environment, which allowed to propose an alternative

mechanism for alloy corrosion and to explain the existing experimental results. We

have shown that their corrosion dissolution is mainly caused by the layered

structure of the phases with the distances between atoms A1-A1 increased by 5-

10% (as compared to the pure aluminium) and also by crystal-oriented areas with

local corrosive adsorption centers evolved due to the partial electron transfer.

These centers lower the activation barrier of aluminium and magnesium atoms

release into the environment.

We have also shown that corrosive resistance of an intermetallide in the

alkaline environment is rather defined by the net charge of the surface than by the

adsorption properties of hydroxide ions. This data was obtained by analyzing the

calculated energies of interatomic bonds in the intermetallide cluster Al 2Cu during

its charge change from Q= –3 to Q= +3, which then defines the electrode

polarization, and by accessing the influence of the corrosion-active ions. We note

that during corrosion the interatomic bond Al-Al is significantly weakened in the
–
–
row of H 2O < OH < Cl while chloride ions decrease the energy of interatomic
interactions almost three times when the surface charge is shifted to the positive

value.

We have studied in details the influence of elastic deformation of

intermetallides on their corrosive interaction with a chloride-containing

environment, which is defined by the layered surface structure (110) of Al 2Cu and

Al 2CuMg, the higher adsorption capability of the chloride-ion as compared to the

surface, and by the increase in the relative bond energy by 20-25% while the

tension deformation of intermetallide clusters reaches 2%. This finding indicates