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Chrome Oxide

Formula: Cr2O3
Alternate Names: Chromium (III) Oxide, Cr2O3, Chromium Oxide

OxideAnalysisFormula
Cr2O3131.58%1.000
Oxide Weight152.00
Formula Weight152.00
If this formula is not unified correctly please contact us.
DENS - Density (Specific Gravity) 5.21
GSPT - Frit Softening Point 1990C M

Chrome oxide is a very refractory ceramic colorant (even a 50% mix with a high borax frit will not even begin to melt it in a crucible). Chrome oxide is the only stable oxide of the metal chromium. It is a bright to dark green crystalline powder insoluble in alkalis and acids. It is manufactured from the mineral Chromite mined in southern Africa, Asia, Turkey and Cuba. As with other powerful coloring agents, chrome must be milled fine enough to eliminate specking in glass or glaze.

Chromium is a 'fast' colorant, meaning can produce strong green colors under all furnace conditions, slow or fast, reducing or oxidizing. It is also a flat colorant (due to its refractory nature), it usually produces an army helmet opaque green. It is powerful, typically only 2% will produce a dark color. It cannot be used to make a metallic glaze.

Chrome oxide is usually employed in raw glazes whereas potassium dichromate is used in fritted glazes.

Since Cr2O3 becomes 2CrO3, oxygen is captured from the surroundings, thus the percentage (or conversion factor) is greater than 100.


How do metal oxides compare in their degrees of melting?

How do metal oxides compare in their degrees of melting?

Metallic oxides with 50% Ferro frit 3134 in crucibles at cone 6ox. Chrome and rutile have not melted, copper and cobalt are extremely active melters. Cobalt and copper have crystallized during cooling, manganese has formed an iridescent glass.

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By Tony Hansen

XML for Import into INSIGHT

<?xml version="1.0" encoding="UTF-8"?> <material name="Chrome Oxide" descrip="" searchkey="Chromium (III) Oxide, Cr2O3, Chromium Oxide" loi="0.00" casnumber="196696-68-1"> <oxides> <oxide symbol="Cr2O3" name="Chrome Oxide" status="" percent="131.580" tolerance=""/> </oxides> </material>


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