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A frit is a ceramic composition that has been fused in a special fusing oven, quenched to form a glass, and granulated. Frits form an important part of the batches used in compounding enamels and ceramic glazes; the purpose of this pre-fusion is to render any soluble and/or toxic components insoluble by causing them to combine with silica and other added oxides.〔''Dictionary of Ceramics'' (3rd Edition) Edited by Dodd, A. Murfin, D. Institute of Materials. 1994.〕 However, not all glass that is fused and quenched in water is frit, as this method of cooling down very hot glass is also widely used in glass manufacture. According to the OED, the origin of the word "frit" dates back to 1662 and is "a calcinated mixture of sand and fluxes ready to be melted in a crucible to make glass". Nowadays, the unheated raw materials of glass making are more commonly called "glass batch". In antiquity, frit could be crushed to make pigments or shaped to create objects. It may also have served as an intermediate material in the manufacture of raw glass. The definition of frit tends to be variable and has proved a thorny issue for scholars. In recent centuries, frits have taken on a number of roles, such as biomaterials and additives to microwave dielectric ceramics. Frit in the form of alumino-silicate can be used in glaze free continuous casting refractories. == Ancient frit == Archaeologists have found evidence of frit in Egypt, Mesopotamia, Europe, and the Mediterranean.〔T. Pradell ''et al.'' 2006, "Physical Processes Involved in Production of the Ancient Pigment, Egyptian Blue," ''Journal of the American Ceramic Society'' 89.4: 1431.〕 The definition of frit as a sintered, polycrystalline, unglazed material can be applied to these archaeological contexts.〔L. Lee and S. Quirke 2000, "Painting Materials," In: P.T. Nicholson and I. Shaw (eds.), ''Ancient Egyptian Materials and Technology'', Cambridge: Cambridge University Press, 109; 〕〔Moorey, P.R.S., 1985, ''Materials and Manufacture in Ancient Mesopotamia'', BAR International Series 237, Oxford: Bar Publications, 134-135; 〕〔Tite, M. S., et al., 1998, "The Use of Copper and Cobalt Colorants in Vitreous Materials in Ancient Egypt," In: S. Colinart and M. Menu (eds.), ''La Couleur Dans La Peinture et L'Émaillage de L'Égypte Ancienne'', Bari: Edipuglia, 112-113.〕 It is typically colored blue or green. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「frit」の詳細全文を読む スポンサード リンク
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