What does chromium oxide do in a glaze? How do you use oxides in ceramics? What does oxide mean in pottery? Is chromium oxide the same as chrome oxide

Cr₂O₃ 

Because of its considerable stability, chromia is a commonly used pigment. It was originally called viridian. It is used in paints, inks, and glasses. It is the colorant in "chrome green" and "institutional green." Chromium(III) oxide is a precursor to the magnetic pigment chromium dioxide, by the following reaction: Along with many other oxides, it is used as a compound when polishing (also called stropping) the edges of knives, razors, surfaces of optical devices, etc. on a piece of leather, balsa, cloth or other material. It is available in powder or wax form, and in this context, it is known as a "green compound".

Chromium(III) Oxide - Uses in Pottery

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. 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.

Formula: Cr₂O₃
Molecular Weight: 151.9904 g/mol
Form: powder
CAS Number: 1308-38-9
Density: 5.22 g/cm³
Synonyms: Chromium(III) oxide, Dichromium trioxide, Chromia, Chromium sesquioxide