Iron Oxide Pigments for Ceramics

1. Characteristics

Iron oxide pigments possess excellent coloring properties. In ceramics, their coloring properties are primarily utilized to create a variety of glaze colors. Due to the varying valence of iron ions, iron oxides exhibit a variety of colors. In addition to the multi-color nature of iron oxide itself, adding iron oxide to other glazes can enhance the glaze's hue and enhance its brilliance. Furthermore, during the ceramic (glaze) manufacturing process, the color of iron oxide varies depending on the firing atmosphere. In an oxidizing flame atmosphere, iron oxide changes color from yellow to reddish brown, then from grape red to brown. In a reducing atmosphere, it exhibits a blue to dark gray color shift. These variations are the result of the dynamic equilibrium and mutual transformation of iron ions within the glaze layer.

2. Applications

Iron oxide pigments are used in seven major categories: architectural ceramics, sanitary ceramics, garden glaze ceramics, art ceramics, household ceramics, industrial ceramics, and specialty ceramics.

Iron oxide as a base material is primarily used in architectural ceramics, including wall and floor tiles, imitation granite, unglazed porcelain tiles, and purple sand pottery. Iron oxide is used in ceramic glazes: It is mainly used to prepare glazes of various colors, such as celadon glaze, rabbit hair glaze, oil drop glaze, star-shaped tortoise-skin glaze, tea-leaf glaze, rust-colored and heron-spotted glaze, and iron-red flower glaze.