Corrosion of Lead Glasses in Acid Media: II, Concentration Profile Measurements

Abstract

Lead concentration profiles were measured in a binary lead silicate glass corroded by acid using ahd a‐backscattering technique. These profiles were characteristic of those predicted for an interdiffusion process and revealed a surface layer deficient in lead. Diffusion coefficients for Pb2+ were calculated, together with values of the total amount of lead removed at the various experimental temperatures and times. Good agreement was found between these data and those previously obtained experimentally. All diffusion coefficient values were high and, correspondingly, activation energy values were low compared with those predicted by the literature for similar glass compositions. This difference was justified from consideration of the leaching process.

Migration Model of Toxic Metals from Ceramic Food Contact Materials into Acid Food

“…Over the past few decades, many pieces of research on migration of lead from ceramic materials have emerged owing to its high toxicity, and a number of empirical, thermodynamic and kinetic mathematical models were reported to describe the migration behaviour of lead. [25][26][27] However, only a few investigations have been conducted on migration of cadmium from ceramic materials, [28][29][30][31][32] and the mechanism and kinetic mathematical models of the cadmium leaching are rare. Therefore, the first purpose of this study was to investigate the leaching mechanisms and kinetics of lead and cadmium from ceramic food contact materials into acid food simulants under various time-temperature conditions.…”

“…Over the past few decades, many pieces of research on migration of lead from ceramic materials have emerged owing to its high toxicity, and a number of empirical, thermodynamic and kinetic mathematical models were reported to describe the migration behaviour of lead . However, only a few investigations have been conducted on migration of cadmium from ceramic materials, and the mechanism and kinetic mathematical models of the cadmium leaching are rare.…”

Modernist enamels: Composition, microstructure and stability

“…The surface altered layer formed is composed of a so called 'hydrated glass' depleted in alkaline elements and an amorphous layer of porous, silica-rich material (often called 'gel'), and, in some cases, by precipitates of secondary insoluble phases. [32,33] In a lead glass, neutral and acidic media corrosion involves also an interdiffusion controlled lead leaching and silica dissolution and reprecipitation [34,35]. Boron is highly soluble while on the contrary, calcium and lead carbonates or sulphates are highly insoluble.…”

“…The kinetics of reaction of the glass surface have been determined in the literature for historical glasses [36] and in particular for potash-lime silicate [37], lead-potash silicate [37], soda and soda-lime borosilicate [32,33] and lead-silicate glasses [34,35] [37]. Alkaline leaching and formation of lead carbonate precipitates was determined in lead-potash silicate enamels after 2 months of exposure.…”

“…Alkaline leaching and formation of lead carbonate precipitates was determined in lead-potash silicate enamels after 2 months of exposure. For lead-silicate glasses typical leached thicknesses of 1-2 µm [34,35] are found after only 162 h exposure although interdiffusion is expected to slow down the process in long term corrosion [33].…”