ANODIC BEHAVIOR OF Zn0.5Al ZINC ALLOY DOPED WITH NEODYMIUM

ABSTRACT

The article discusses the experimental results on the study of the effect of neodymium additives on the anodic behavior of the Zn0.5Al zinc alloy.

АННОТАЦИЯ

В статье рассматриваются экспериментальные результаты по изучению влияния добавок неодима на анодное поведение цинкового сплава Zn0.5Al.

Keywords: Zn0.5Al alloy, neodymium, potentiostatic method, speed of corrosion, anodic behavior.

Ключевые слова: сплав Zn0.5Al, неодим, потенциостатический метод, скорость коррозии, анодное поведение.

Introduction. The particular importance is the use of means and methods of combating various types of corrosion, which is important for ensuring the prospects for the development of technical progress in the field of modern industry. [1]. Zinc and aluminum-zinc protective coatings today occupies a leading position in the field of coating the surfaces of structures and various products made of low-, medium- and high-carbon steels, therefore, they will protect these structures from corrosion [2, 3]. The results of the development and study of various properties of Zn-Al alloy coatings with a number of elements of the table of the periodic system are discussed in [4-6]. Also in [7-9] some information is given about the significant behavior of these alloys as an anode-coating in various corrosive environments.

Objective. The purpose of this work is to study the effect of neodymium additives on the anodic behavior of Zn0.5Al zinc alloy in an acidic environment.

Methods. When conducting corrosion studies of alloys with the participation of neodymium of various concentrations, a potentiostatic method was used [10].

Results. The time dependence of the free corrosion potential of alloys plays an important role in establishing surface passivity in acidic environment. Changes in the free corrosion potential of the Zn0.5Al zinc alloy doped with neodymium, in time, in environments of the HCl electrolyte, were recorded for one hour. They indicated the potential shift to the positive side which is observed for all studied groups of alloys. Stabilization of alloys occurs by 35 minutes of the corrosion process (table 1).

Table 1.

Changes in the free corrosion potential (-E_f.corr., V) of the Zn0.5Al alloy doped neodymium, in time

However, the potentials of corrosion, pitting formation and repassivation shift into the positive area resulting in a further increase in the amount of the doped components before 0.5 wt% neodymium. It was found that with an increase in the concentration of hydrochloric acid electrolyte and doped component, the corrosion potential desrease, which indirectly indicates a desrease in the anticorrosion resistant of alloys as the aggressiveness of the corrosive environment increases (table 2).

Table 2.

Anode characteristics of Zn0.5Al zinc alloy doped with neodymium

Generally, alloys with additives neodymium within 0.01÷0.1 wt% have low values of anodic corrosion rate as compared to the initial Zn0.5Al zinc alloy.

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