what is the enamel on cast iron pans
Cast-iron cookware Enameled cast iron is cast iron that has a vitreous enamel glaze. The enamel coating over the cast iron prevents rusting, eliminates the need to season the metal, and allows more thorough cleaning. Furthermore, pigments used in the enameling process can produce vibrant colors. While enamel-coated cast iron doesn't have the seasoning and cleaning issues of bare cast iron, it can be several times more costly, and does not have some of the benefits of bare cast iron, such as the ability to withstand searing heat and resist sticking. It limits the leaching of dietary iron, and chipping of the enamel coating can be a concern.
Lead glass The fluxing and refractive properties valued for lead glass also make it attractive as a pottery or ceramic glaze. Lead glazes first appear in first century BC to first century AD Roman wares, and occur nearly simultaneously in China. They were very high in lead, 45–60% PbO, with a very low alkali content, less than 2%.[13] From the Roman period, they remained popular through the Byzantine and Islamic periods in the Near East, on pottery vessels and tiles throughout medieval Europe, and up to the present day. In China, similar glazes were used from the twelfth century for colored enamels on stoneware, and on porcelain from the fourteenth century. These could be applied in three different ways. Lead could be added directly to a ceramic body in the form of a lead compound in suspension, either from galena (PbS), red lead (Pb3O4), white lead (2PbCO3·Pb(OH)2), or lead oxide (PbO). The second method involves mixing the lead compound with silica, which is then placed in suspension and applied directly. The third method involves fritting the lead compound with silica, powdering the mixture, and suspending and applying it.[13] The method used on a particular vessel may be deduced by analysing the interaction layer between the glaze and the ceramic body microscopically.