Effect of Different Welding Processes on Electrochemical and Corrosion Behavior of Pure Nickel in 1 M NaCl Solution

Abstract

Abstract:A plasma arc welding (PAW)-tungsten inert gas (TIG) hybrid welding process is proposed to weld pure nickel. In PAW-TIG welding, the arc of the PAW was first to be ignited, then TIG was ignited, while in PAW welding, only the PAW arc was launched. This paper investigated the effect of different welding processes on electrochemical and corrosion performance of between a pure nickel joint and a base metal in an aerated 1 M NaCl solution, respectively. The average grain size of the joint fabricated by PAW welding (denoted as J P joint) is 463.57 µm, the joint fabricated by PAW-TIG welding(denoted as J P-T joint) is 547.32 µm, and the base metal (BM) is 47.32 µm. In this work, the passivity behaviors of samples were characterized for two welding processes by electrochemical impedance spectroscopy (EIS), open circuit potential versus immersion time (OCP-t), and the potentiodynamic polarization plots. EIS spectra, attained with different immersion times, were analyzed and fitted by an equivalent electrical circuit. Photomicrographs of BM, J P , and J P-T were also taken with a scanning electron microscope (SEM) to reveal the morphological structure of the pit surfaces. Electrochemical tests show that the sequence of the corrosion resistance is BM > J P > J P-T . The size and quantity of the hemispherical corrosion pits of all samples are different. The corrosion morphology observations found a consistency with the consequence of the electrochemical measurements. The results show that an increase of the grain dimensions due to different heat treatments decreased the pure nickel stability to pitting corrosion.

Relationship between corrosion and nanoscale friction on a metallic glass

“…As the immersion continues, the friction coefficient of the outer layer increases sublinearly with immersion time in phosphate buffer (Figure 5c). The corrosion resistance of the oxide film in passivating solutions was reported to increase with time during the first stage and then remain almost constant after a longer immersion time [43][44][45]. We suggest a similar development for MGs in phosphate buffer, where the protective effect of the inner layer becomes stronger with the immersion time, the dissolution becomes slower, and the growth rate of the outer layer decreases.…”

Relationship between corrosion and nanoscale friction on a metallic glass

“…As the immersion continues, the friction coefficient of the outer layer increases sublinearly with immersion time in phosphate buffer ( Figure 5c ). The corrosion resistance of the oxide film in passivating solutions was reported to increase with time during the first stage and then remain almost constant after a longer immersion time [ 43 – 45 ]. We suggest a similar development for MGs in phosphate buffer, where the protective effect of the inner layer becomes stronger with the immersion time, the dissolution becomes slower, and the growth rate of the outer layer decreases.…”

Formation and Corrosion Behavior of Nickel/Alumina Nanocomposites

“…Table 1 shows the parameters characterizing the corrosion process of identical experimental samples, obtained by extrapolating the polarization curves. For comparison, the table also presents data for metallurgical Ni, a continuous thick Ni film obtained by electrochemical deposition, and a thin nanocrystalline Ni film obtained by magnetron sputtering [13][14][15][16]. 1 that Ni nanopillars protected by alumina are more resistant to dissolution processes than massive, metallurgical nickel [16] or electrochemically deposited thick nickel films [14].…”