Ceramic colorants

Ceramic colorants

'Ceramic colorants' are added to a glaze or a clay to create color. Carbonates and oxides of certain metals, characterize most colorants including the commonly used cobalt carbonate, cobalt oxide, chrome oxide, red iron oxide, and copper carbonate. These colorants can create a multitude of colors depending on other materials they interact with and to which temperature and in which atmosphere they are fired.

Contents

Cobalt

Cobalt is commonly used in either its carbonate (CoCO3) or its oxide (Co3O4) forms. In the presence of most fluxes, it yields blue colors ranging from low saturation pastels to high saturation midnight blues in both oxidation and reduction atmospheres. However, in the presence of magnesium, cobalt can become purple, pink or reddish blue depending on whether it was fired in oxidation (yields purple) or reduction. Cobalt is also commonly used in black glazes and in washes as decorative medium. Common saturation percentages for low saturation range from (.25 to .5%) and in high saturation from (1 to 2%).

Chrome

"Chrome is a rather versatile and fickle colorant," (Chappell). Chrome oxide (Cr2O3) is commonly used for achieving greens. However, in the presence of zinc, chrome can produce brown. Glazes with tin oxide present will often blush to pink if fumed with chrome or if chrome is present in the glaze with the tin, often intense pinks occur. If fired above cone ^6, chrome will fume and become a gas in the kiln. Common saturation percentages for chrome at low saturation range from (.25 to .5%) and at higher percentages from (1 to 2%). Chrome is a refractory.

Red Iron

Iron is commonly used as a colorant in its red iron oxide form as (Fe2O3). Red iron oxide is commonly used to produce earthy reds and browns. It is the metal responsible for making earthenwares red. Iron is also another tricky colorant because of its ability to yield different colors under different circumstances. At low percentages (.5-1%) and in the presence of potassium, iron will become light blue or light blue-green in reduction (as is seen in traditional celadons). In the presence of barium, iron may become yellow green. When used in combination with calcium, red iron oxide can become pale yellow or amber in oxidation or green in reduction. Common percentages for red iron oxide range from (4 up to 10%).

Copper

Copper's carbonate form (CuCO3) is commonly used to produce greens, turquoise, and copper reds. If need be, copper oxide (CuO) can be substituted but has a larger particle size and glazes should be adjusted to generally half the amount called for. In barium based glazes greenish blues often result from copper. Alkaline feldspar glazes with copper fired in reduction atmospheres will often yield ox blood or copper red glazes discovered by the Chinese. When fired above cone ^8 copper can become unstable and will often fume off of a glaze in vapor form.

References

Clay and Glazes: Revised edition. Chappell, James. Watson-Guptill Publications, New York. 1991.

Glazes for the Craft Potter. Fraser, Harry. Watson Guptill Publications, New York. 1974.

Clay and Glaze for the Potter. Rhodes, Daniel. Krause Publications. 2000. Expanded and Revised by Robin Hopper.


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Ceramic glaze — Composite body, painted, and glazed bottle. Dated 16th century. From Iran. New York Metropolitan Museum of Art. Glaze is a layer or coating of a vitreous substance which has been fired to fuse to a ceramic object to color, decorate, strengthen or …   Wikipedia

  • art conservation and restoration — Maintenance and preservation of works of art, their protection from future damage, deterioration, or neglect, and the repair or renovation of works that have deteriorated or been damaged. Research in art history has relied heavily on 20th and… …   Universalium

  • Pottery — Pot and Pots redirect here. For Pot, see Pot (disambiguation). For POTS, see POTS (disambiguation). Unfired green ware pottery on a traditional drying rack at Conner Prairie living history museum …   Wikipedia

  • Early modern glass in England — The early modern period in England (c. 1500 1800) brought on a revival in local glass production. Medieval glass had been limited to the small scale production of forest glass for window glass and vessels, predominantly in the WealdKenyon, G.H.,… …   Wikipedia

  • Transparency and translucency — Diaphanes redirects here. For the genus of firefly, see Diaphanes (beetle). Translucence redirects here. For other uses, see Translucence (disambiguation). Translucent redirects here. For the Japanese manga series, see Translucent (manga).… …   Wikipedia

  • Différents types de laser — Liste des différents types de laser Ceci est une liste des différents types de lasers avec la longueur d onde sur laquelle ils opèrent et leurs applications. Il existe plusieurs milliers de sortes de lasers mais la plupart d entre eux ne sont… …   Wikipédia en Français

  • Liste des différents types de laser — Ceci est une liste des différents types de lasers avec la longueur d onde sur laquelle ils opèrent et leurs applications. Il existe plusieurs milliers de sortes de lasers mais la plupart d entre eux ne sont utilisés que dans le cadre de… …   Wikipédia en Français

  • Pigment — For the drug referred to as pigment, see black tar heroin. Natural ultramarine pigment in powdered form …   Wikipedia

  • Mortar (masonry) — For other uses, see Mortar (disambiguation). Mortar holding weathered bricks Mortar is a workable paste used to bind construction blocks together and fill the gaps between them. The blocks may be stone, brick, cinder blocks, etc. Mortar becomes… …   Wikipedia

  • marble — 1. noun /ˈmɑːbəl,ˈmɑɻbəl/ a) A rock of crystalline limestone. Open thy marble jaws, O tomb / And hide me, earth, in thy dark womb. b) A small spherical ball of rock, glass, ceramic or metal used in childrens games. 2. verb /ˈmɑːbəl,ˈmɑɻbəl/ a) To …   Wiktionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”