Digitalfire Ceramic Oxides Directory



MnO2 (Manganese Dioxide)

FamilyColorant
Weight86.900
COLE - Co-efficient of Linear Expansion 0.050

Notes

-Manganese dioxide exists only below 1080C, above which the dioxide form disassociates to release its oxygen (see MnO for more information).

-Manganese is a colorant using in bodies and glazes, producing blacks, browns, and purples.

-Manganese is a constituent in many igneous rocks, and thus occurs in many clays weathered from these parent rocks. In most cases it is a very minor oxide, but does occur in much greater amounts in some slip and highly stained materials. It is thus a color contributor in many traditional and historic slip glazes.

-Smaller amounts are easily dissolved in most glaze melts, however, around the 5% threshold, the manganese will precipitate and crystallize. In large amounts in a glaze (i.e. 20%), metallic surfaces are likely.

-In glazes below 1080C, it can give coffee color browns when used with tin.

Mechanisms

  • Glaze Color - Black

    Manganese and cobalt mixture produce black. Iron can also be used. For example, a mix of 8 iron, 4 manganese dioxide and 0.5 cobalt make a raw black stain.

  • Glaze Color - Purple, Violet

    Purple colors can be produced in glazes of high alkali (KNaO) and low alumina, especially in combinations with cobalt (look for a frit with this profile for best results).

Out Bound Links

  • (Materials - Closest material equivalent) Manganese Dioxide - MnO2

    Mno2, Pyrolusite, Manganese(IV) oxide

  • (Articles)

    An Overview of Ceramic Stains

    Understanding the advantages of disadvantages of stains vs. oxide colors is the key to choosing the ...

  • (Materials - Material source) Stain

    Ceramic Stains




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