Glazing, of pottery

Patented proposals have been made to heat sodium chloride with phosphoric acid (A. Delhaye) zinc or lead pyrophosphate (L. J. F. Margueritte) or ferric phosphate (A. R. Arrott). The resulting soluble sodium phosphate is decomposed by boiling with lime to form sodium hydroxide, which, if needed, can be converted into carbonate by a current of carbon dioxide. These methods are quite impracticable. In 1809, J. L. Gay Lussac and L. J. Thenard proposed to make soda by the action of steam on a mixture of sodium chloride and silica If these two compounds are melted together there is very little action, for the salt volatilizes before anything but a superficial combination takes place, and the action of salt in the glazing of pottery is probably made possible by the aq. vapour in the furnace gases. The sodium silicate formed by the joint action of sodium and... 

Lead oxide has been widely used in the glazing of pottery in flint -type glasses and in solder glasses, but these materials contain no carbon and have no visible structure In the process being reported, carbon contained in the cotton is required for formation of the new chemical structure and for retention of the fabric weave pattern and shape in the new products ... 

The main use of lead metaborate is in glazes on pottery, porcelain, and chinaware, as weU as in enamels for cast iron. Other appHcations include as radiation-shielding plastics, as a gelatinous thermal insulator containing asbestos fibers for neutron shielding, and as an additive to improve the properties of semiconducting materials used in thermistors (137). 

Pottery is one of the oldest materials. Clay artefacts as old as the pyramids (5000 bc) are sophisticated in their manufacture and glazing and shards of pottery of much earlier date are known. Then, as now, the clay was mined from sites where weathering had deposited them, hydroplastieally formed, fired and then glazed. 

OSL Acronym for optically stimulated luminescence. oven A furnace used at relatively low temperatures, overglaze Pigment applied to the surface of pottery after glazing. oxidation A type of chemical reactions in which an atom or atomic group combines with oxygen or one or more electrons are removed from it. oxide A substance composed by the chemical combination of oxygen with another element. 

Gersberg RM, Gaynor K, Tenczar D, et al. 1997. Quantitative modeling of lead exposure from glazed ceramic pottery in childhood lead poisoning cases. International Journal of Environmental Health Research 7(3) 193-202. 

This oxide is used in making blue and green colored glass and in glazes for pottery, but in recent years the preparation of superconducting materials such as YBa2Cu307 has become a serious interest. Other materials containing mixed oxides have also been produced. 

Examples have been sometimes discovered in this country, and also in various other places, of glazed Roman pottery of a much paler red than the Samian, and altogether inferior to that celebrated ware. Other rare varieties are grey, yellow, brown, orange, or black j these wares sometimes have a lustrous glaze which shows the color of the paste, and in other examples the glaze has various hueB of its own. 

Earthenware.—Under the term earthenware are embraced many varieties of pottery, which in fracture have all an. earthy appearance, "hro perfectly opaque, and are coated with a soft, easily fusible glaze,... 

Glazes for pottery are described much as in the earlier divisions of the work, but here lead glazes are described. 

One of the potentially more productive avenues of research using LA-ICP-MS involves the characterization of paints and glazes used in the decoration of pottery. Just as bulk analysis of clays by INAA, XRF, ICP-MS, and other analytical methods have demonstrated to be a productive avenue of research for making interpretations regarding past cultural systems, chemical characterization... 

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