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Minton majolica game pie dish, lead-glazed earthenware, c. 1875, an iconic example of High Victorian appetite for innovation with humour/whimsy, coloured lead glazes. Lead-glazed earthenware is one of the traditional types of earthenware with a ceramic glaze, which coats the ceramic bisque body and renders it impervious to liquids, as ...
A ceramic flux functions by promoting partial or complete liquefaction. [1] [2] The most commonly used fluxing oxides in a ceramic glaze contain lead, sodium, potassium, lithium, calcium, magnesium, barium, zinc, strontium, and manganese. These are introduced to the raw glaze as compounds, for example lead as lead oxide.
Galena is the primary ore of lead, and is often mined for its silver content. [6] It is used as a source of lead in ceramic glaze. [27] Galena is a semiconductor with a small band gap of about 0.4 eV, which found use in early wireless communication systems.
A high-lead glaze has a linear expansion coefficient of between 5 and 7×10 −6 /°C, compared to 9 to 10×10 −6 /°C for alkali glazes. Those of earthenware ceramics vary between 3 and 5×10 −6 /°C for non-calcareous bodies and 5 to 7×10 −6 /°C for calcareous clays, or those containing 15–25% CaO. [16] Therefore, the thermal ...
Ceramic industries are reluctant to use lead alternatives since leaded glazes provide products with a brilliant shine and smooth surface. The United States Environmental Protection Agency has experimented with a dual glaze, barium alternative to lead, but they were unsuccessful in achieving the same optical effect as leaded glazes.
Sancai is a type of lead-glazed earthenware: lead oxide was the principal flux in the glaze, often mixed with quartz in the proportion of 3:1. [6] The polychrome effect was obtained by using as colouring agents copper (which turns green), iron (which turns brownish yellow), and less often manganese and cobalt (which turns blue).
Creamware is made from white clays from Dorset and Devon combined with an amount of calcined flint.This body is the same as that used for salt-glazed stoneware, but it is fired to a lower temperature (around 800 °C as opposed to 1,100 to 1,200 °C) and glazed with lead to form a cream-coloured earthenware. [11]
Metlox Pottery was founded in 1927 by Theodor C. Prouty and his son Willis Prouty, originally as a producer of outdoor ceramic signs. After the death of T.C. in 1931, Willis renamed the company Metlox Pottery ("Metlox" is a combination of "metal" and "oxide," a reference to the glaze pigments), and began producing dinnerware.
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