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Na2O (Sodium Oxide, Soda)
Notes-Soda is a slightly more powerful flux than potassium. Together with potassium and lithium oxides, it is classified as one of the Alkaline group.-Sodium is a useful flux over the entire temperature range from 900-1300C. It is very active at higher tempeature ranges. -Sodium can begin to volatilize at high temperatures. -Soda should be used in moderate amounts because it has a higher expansion than any other oxide and will promote crazing in glazes lacking silica or alumina. Also it decreases tensile strength and elasticity compared to other common bases. High soda glazes can often be soluble and easily scratched. -Gives strong color responses to copper, cobalt, and iron. Low alumina in high alkali glazes gives the most intense colors. However the color can come at the expense of glaze fit and excessive fluidity because high soda is required. High alkali glazes definitely tend to craze. If the color depends on this (i.e. copper blue) then it may be necessary to adjust the body to eliminate crazing since a reduction of the alkalis to reduce crazing will mean a loss of color. -Soda works well with boric oxide (and also lithia and potassium) in low temperature lead-free glazes. -The alkalis can increase lead solubility. Mechanisms
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