Cobalt green
| Identifiers | |
|---|---|
| Properties | |
| CoZnO2 | |
| Appearance | green paste, linseed oil odor |
| Insoluble in water and most petroleum solvents | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
|
eye contact |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |
Cobalt green, sometimes known as Rinman's green or Zinc Green, is a translucent green pigment made by heating a mixture of cobalt(II) oxide and zinc oxide. Sven Rinman, a Swedish chemist, discovered this compound in 1780. Although it is stable and can be safely mixed with other pigments, it is rarely used because it is a weak pigment for its cost.
Some Cobalt Greens are derived from doping Co(II) into Mg(II) and Zn(II) sites of Mg2TiO4 and Zn2TiO4, respectively.[1]
Background
Zinc oxide pigments have a mix of white pigments and individual crystals that appear to be colorless and because of their particle size, its ability to accept an acid in a mixture, and compatibility with countless natural and unnatural systems; it is used in many industries and processes.[2][3] Since zinc is used in many paint films, acids depend on the zinc oxide to avoid extra catalyzed degradation of the binder. When zinc oxide is mixed with a cobalt oxide, the compound creates an intense green color and can further be used as medium-temperature pigments. The formation chemistry, which is based on the mutual suppression of the crystal lattices, and the low content of cobalt, helps this compound gain interest. The purpose of this compound is to try and prepare an innovative cost-effectively friendly green-colored inorganic pigment.[4] Unfortunately, the pigment was never an artist’s favorite, as it has poor tinting and covering strength. However it has excellent lightfastness (due to its high zinc content) and its transparency makes it ideal for glazing.[5]
Color is an important characteristic of many ceramic products.[6] Pigments with cobalt-based ceramics are generally used for colored glazes in the ceramic industries for floor or wall whitewares.[7] Ceramic pigments are considered to be inorganic crystalline structures that develop a stable color.[8] They have a high resistance with respect to light, environment, and high temperature chemicals. The broad horizon of their colors is quite large: green, blue, violet, yellow, black and brown.[9] Synthetic approaches such as sol-gel technology, solution combustion method, polymeric precursor method, and so on are using cobalt-based pigments more recently.[10]
Research
Cobalt Green has been tested for use in “spintronic” devices. Cobalt green is attractive in this application because it is magnetic at room temperature.[11]
See also
References
- ^ Völz, Hans G. et al. "Pigments, Inorganic" in Ullmann's Encyclopedia of Industrial Chemistry, 2006 Wiley-VCH, Weinheim. doi:10.1002/14356007.a20_243.pub2.
- ^ The Effect of cobalt oxide on zinc oxide in a new anticorrosive green pigment. Ahmed, Nivin, Emerald Group Publishing Limited. Vol. 0003-5599, Issue 0003-5599, pg. 0003.
- ^ Spectroscopic analysis of blue cobalt smalt pigment Jonynaite, D. Vibrational spectroscopy, Vol. 52, Issue 2, pg. 158, 2010
- ^ The Effect of cobalt oxide on zinc oxide in a new anticorrosive green pigment. Ahmed, Nivin, Emerald Group Publishing Limited. Vol. 0003-5599, Issue 0003-5599, pg. 0003.
- ^ http://www.webexhibits.org/pigments/indiv/overview/cogreen.html
- ^ Formation and the colour development in cobalt spinel pigments. Fernandez, Ana L. Journal of Pigment and resin technology, Vol. 31, Issue 6, pg. 350, 2002
- ^ Spectroscopic analysis of blue cobalt smalt pigment Jonynaite, D. Vibrational spectroscopy, Vol. 52, Issue 2, pg. 158, 2010
- ^ Effect of adding zinc on the properties of cobalt-containing ceramic pigments prepared from layered double hydroxides. Perez-Bernal, ME. Journal of Solid State Chemistry; Vol. 182, Issue 9, pg. 3566; 2009
- ^ Spectroscopic analysis of blue cobalt smalt pigment Jonynaite, D. Vibrational spectroscopy, Vol. 52, Issue 2, pg. 158, 2010
- ^ Investigation of Historical Analogues and Sol-Gel preparation of novel Inorganic cobalt-based pigments. Barkauskas, Jurgis, Lithuanian Academic Libraries Network (LABT) Vilnius University 2011-02-22
- ^ Green Pigment Spins Chip Promise. August 2006, news.bbc.co.uk/2/hi/technology/4776479.stm