journal article·2023-08-14Open access

Metallurgical pathways of lead leaching from brass

Te Zhu, Wei Li, Jonathan Chun Ming Kwok, Kai Wing Siu, Lu Yin, Alfonso Hing Wan Ngan

npj Materials Degradation· Volume 7· Issue 1

Abstract

Abstract Leaded (Pb) brass components used in water pipeworks are prone to lead leaching following soldering or brazing during installation. Synchrotron radiation X-ray imaging shows that in the initial state of potable-water grade brass samples, Pb exists mainly as isolated or linked-together particles from sub-micron to several microns large. On heating to the usual soldering temperature of ~200 °C, the Pb contents surface rapidly via diffusion pathways involving an interpenetrating Pb–brass structure with orientation relationship (11 $$\bar{1}$$ ) α-brass //(220) Pb ; [011] α-brass //[ $$\bar{1}$$ 13] Pb . On heating to the usual brazing temperature of 700 °C, the Pb particles melt and expand in volume, with the Pb content forced into the brass lattice preferentially along {101} α-brass planes, forming Pb phase of low sphericity or even large sheets. On immersion in water, the surfaced Pb particles are oxidized to form PbO needles along the normal direction of { $$\bar{2}\bar{2}2$$ } PbO planes, which are then easily washed away to cause Pb leaching.
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Research context

OpenAlex topics: Nanoporous metals and alloys · Metallurgy and Material Science · Recycling and Waste Management Techniques

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

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