Comportamento corrosivo de soldas à fricção FSW do tipo alumínio-cobre

Abstract

3-Glycidoxypropyl-trimethoxy-silane was used as a preventive measure for corrosion control in 6060-T5 aluminum alloy (AA 6060-T5) and ASTM-B110 copper (Cu ASTM-B110) joined by friction stir welding (FSW). The substrates of the AA 6060-T5/Cu ASTM-B110 stir welding joint were cut using a precision cutting machine (ISOMET 2000) and etched with two different solutions: H2O: NH4OH:H2O2 (0.45: 0.45: 0.1 v/v) at the Cu ASTM-B-110 joint surface and 0.5% (v/v) HF at the AA 6060-T5 joint. A good mixing of AA 6060-T5 and Cu ASTM-B110 was observed in the weld nugget zone (WNZ) according to observations by optical microscopy. The effect of the 3-glycidoxypropyl-trimethoxy-silane deposited on the surfaces of these materials following immersion in 0.05 mol L-1 NaCl was investigated by electrochemical methods. The results, mainly the inductive behavior at low frequencies, show that the coating of the alloys AA 6060-T5 and Cu ASTM-B110, and the welding joint (AA 6060-T5/Cu ASTM-B110) with 3-glycidoxypropyl-trimethoxy-silane leads to a decrease in the corrosion rate on exposure to a chloride solution in comparison with non-coated materials. This feature characterizes this treatment as an alternative approach to retarding corrosion processes, particularly the strong galvanic corrosion that commonly occurs at the AA 6060-T5/Cu ASTM-B110 welding joint.