Abstract
Some α + β’ brass components of drinking water distribution systems in Morocco underwent early failures and were investigated to assess the nature and extent of the corrosion attacks. They exhibited different corrosion forms, often accompanied by extensive β’ dezincification. In order to offer viable alternatives to these traditional low cost materials, the corrosion behavior of two representative α + β’ brass components was compared to that of brass alloys with nominal compositions CuZn36Pb2As and CuZn21Si3P, marketed as dezincification resistant. CuZn21Si3P is a recently developed eco-friendly brass produced without any arsenic or lead. Electrochemical tests in simulated drinking water showed that after 10 days of immersion CuZn21Si3P exhibited the highest polarization resistance (Rp) values but after longer immersion periods its Rp values became comparable or lower than those of the other alloys. After 150 days, scanning electron microscope coupled to energy dispersive spectroscopy (SEM-EDS) analyses evidenced that the highest dezincification resistance was afforded by CuZn36Pb2As (longitudinal section of extruded bar), exhibiting dealloying and subsequent oxidation of β’ only at a small depth. Limited surface dealloying was also found on CuZn21Si3P, which underwent selective silicon and zinc dissolution and negligible inner oxidation of both α and κ constituent phases, likely due to peculiar galvanic effects.
Highlights
Corrosion is an important technological economic and social problem which can be controlled after full knowledge of the alloy behavior under field conditions and proper choice of materials and design solutions [1,2,3]
In B2, scanning electron microscope (SEM)-energy dispersive spectroscopy (EDS) analysis detected tiny particles of a third bright phase (Figure 3a), which was located at the grain boundaries and corresponded to the cubic γ phase with nominal composition Cu4ZnSi [18]
The early failures detected on the F1–7 components of drinking water distribution systems in Morocco are mostly connected to their high contents of β’ phase, which undergoes dezincification and selective dissolution attacks (Figure 4)
Summary
Corrosion is an important technological economic and social problem which can be controlled after full knowledge of the alloy behavior under field conditions and proper choice of materials and design solutions [1,2,3]. In the case of brass corrosion, the large-scale use of these alloys in drinking water distribution systems for tube fittings, valves, and ancillaries may determine human health concerns due to Pb and Cu release in drinking water [4,5,6]. Zinc concentrations up to 35% may dissolve in face-centered cubic (fcc) copper matrix to form a single solid solution (α brass). When an even higher zinc content is added, a zinc-rich β’ second phase forms, characterized by body-centred cubic (bcc) lattice. Duplex α + β’ brasses are cheaper, easier to fabricate and exhibit higher mechanical strength than α brasses, but the zinc-rich β’ phase exhibits a higher
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
