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Application of Iron Oxide Yellow
Addtime: 2017/05/26 Read:5230 Font size: Large Small
This is one of the many colors of iron oxide. More accurately, it is an iron hydroxide. Yellow ochre clay contains iron oxide yellow. In ceramics iron oxide red is most commonly used in glazes and clay bodies, but black is also used. Yellow is the least color-stable form. Iron oxide yellow is a synthetic material of very fine particle size (but not as fine as black or red).
Actual iron oxide yellow are around 85% Fe2O3 and about 12% LOI with some impurities.
Theoretically, any form of iron could be used to source Fe in the fired ceramic product (of course they lose different amounts of volatiles on firing so they cannot be substituted gram-for-gram). However in practice this is not the case. Iron oxide yellow, in our tests, for example, does not stain a glaze but it does stain a clay body. The reason is not apparent.
Iron oxide yellow can be used where raw color or other raw properties are important to the manufacturing process or color of the unfired product and where a less messy material is desired. Iron oxide yellow is not as fluffy and light as black, but more than red. It does not agglomerate as badly as red, but more than black. It is coarser in particle size and does leave some lighter colored residue on a 325 mesh screen (up to 8% in one specimen we tested whereas the others left zero).
Iron oxide yellow is also used in paints, enamels, concrete colorants, plastics, rubber, and paper where permanent yellow is required. It has excellent hiding power, absorbs ultraviolet light, is compatible with a broad range of vehicles, disperses well in aqueous and solvent systems, does not contain heavy metals.
One process of manufacture involves precipitation of ferric oxyhydroxide followed by purification through washing, drying and milling.
This article comes from digitalfire edit released
