Corrosion protection of the AA2198‐T8 alloy by environmentally friendly organic‐inorganic sol‐gel coating based on bis‐1,2‐(triethoxysilyl) ethane

Abstract

In this work, a surface coating composed of organic‐inorganic hybrid sol‐gel based on bis‐1,2‐(triethoxysilyl) (BTSE) ethane was applied on AA2198‐T8 samples, and its effect on corrosion resistance was investigated and compared with that of a chromate layer formed in a solution with hexavalent chromium ions. The corrosion resistance of BTSE coated samples was evaluated by immersion tests in sodium chloride solution (0.005 mol/L NaCl) and monitored by global electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and local electrochemical techniques such as scanning vibrating electrode technique (SVET) and scanning electrochemical microscopy (SECM). The formed coating layers were characterized by X‐ray photoelectron spectroscopy (XPS). The results pointed out that the BTSE is an effective alternative coating for corrosion protection of new generation Al‐Cu‐Li alloys and could replace chromates obtained in toxic and carcinogenic CrVI containing solutions leading to improved corrosion protection.

TSA anodising voltage effects on the near-surface coarse intermetallic particles in the AA2024-T3 and AA2198-T8 alloys

“…The AA2198 alloy has been the object of numerous corrosion studies [4,11,30,42,43,88 93]. However, the behaviour of the coarse intermetallic particles during anodising has not yet been reported.…”

Application of Commercial Surface Pretreatments on the Formation of Cerium Conversion Coating (CeCC) over High-Strength Aluminum Alloys 2024-T3 and 7075-T6

“…Great efforts have been made in order to look for alternatives to CrCC [12]. The great number of possibilities includes conversion coatings based on trivalent chromium [13], rare earths chemical conversion coatings [14,15], Zr/Ti-based chemical conversion coatings [16], sol-gel coatings [17], and smart coatings providing selfhealing protection [12,18,19]. However, none of these options has achieved a true industrial application capable of replacing CrCC and the scientific community continues to search for an alternative.…”