Corrosion of the Welded Aluminium Alloy in 0.5 M NaCl Solution. Part 1: Specificity of Development

Abstract

This work consists of two parts. In the first part, the kinetics and mechanism of corrosion on the surface of the welded joint area of the aircraft 1579 aluminium alloy have been studied using SVET (scanning vibrating electrode technique) and SIET (scanning ion-selective electrode technique) in 0.5 M NaCl. The results have revealed the corrosion process development within the weld interface due to the presence of microdefects in the morphological structure. Features of the 1579 Al alloy corrosion have also been investigated through immersion experiments, quantitative analysis of dissolved alloying elements by means of atomic absorption spectroscopy, and corrosion products characterization using XRD (X-ray diffraction) analysis. The presence of Mg as an alloying element in the 1579 Al alloy sufficiently increases the bulk pH values as a result of the intensive dissolution of Mg. These factors accelerate the corrosion activity of the studied material in the 0.5 M NaCl solution. Corrosion evolution analysis of the 1579 Al alloy sample showed the importance of the coating formation to protect this alloy against corrosion and to increase the stability of this system in the corrosive media.

Effect of Microstructure on the Corrosion Resistance of TIG Welded 1579 Alloy

“…Composition of this aluminum alloy (Al-Mg-Sc system) is presented in Table 1. Tungsten inert gas (TIG) welding process, cross-section formation, and surface mechanical treatment were described in [20]. TIG welding was carried out using high purity argon (shield gas) with the flow rate equaled to 43 ± 3 L min −1 .…”

“…The electrochemical activity of the bare sample, as well as the anticorrosion properties upgrade after PEO treatment, were studied using Scanning Ion-Selective Electrode Technique (SIET) and Scanning Vibrating Electrode Technique (SVET) on equipment supplied by Applicable Electronics (Applicable Electronics, New Haven, CT, USA). The detailed methodology of SVET-SIET tests was described in [20].…”

“…This study is a continuation of the work [20], where preliminary investigations of the electrochemical properties of the welded joint were performed. In the current work to reveal the reason of high electrochemical activity of the weld interface, the microstructure of the material and chemical composition of the specific phases, which are activators of the material corrosion, were studied.…”

“…Aluminum alloys of the Al-Mg-Sc system combine such properties as medium-strength, high corrosion resistance and possess high weldability. In our previous studies [20,21] we have established using localized electrochemical methods that weld interface of 1579 Al alloy is an area, where corrosion starts. At the same time, we have not correlated this specific place of weld interface, where the corrosion process occurred, with the microstructure of the material.…”

Natrium Karbonat : Termodinamika dan Transport Ion

“…mengalami persaingan dengan proses Solvay. Diawal tahun 1800-an, penyelidikan dilakukan pada industri tersebut yaitu dilakukannya reaksi dekomposisi ganda antara NaCl (47)(48)(49)(50)(51)(52)(53)(54)(55) dengan NH 4 HCO 3 , namun tidak berhasil. Pada akhirnya Ernest solvay Belgia (1838 -1932) membawa perkembangan proses Solvay ini ketitik kesuksesan yaitu pada tahun1861 -1865.…”