Zinc chromate
| Zinc chromate | ||
|---|---|---|
| IUPAC name Zinc chromate | ||
| Identifiers | ||
| CAS number | 13530-65-9  | |
| PubChem | 26089 | |
| RTECS number | GB3290000 | |
| Properties | ||
| Molecular formula | ZnCrO4 | |
| Molar mass | 181.403 g/mol | |
| Appearance | yellow-green crystals | |
| Density | 3.43 g/cm3 | |
| Melting point | 316 °C | |
| Boiling point | 732 °C | |
| Solubility in water | insoluble | |
| Hazards | ||
| EU classification | not listed | |
| NFPA 704 |
 0
2
0
OX
| |
| U.S. Permissible exposure limit (PEL) |
0.1 mg/m3[1] | |
| LD50 | 0.5 to 5 g/kg | |
(verify) (what is: / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | ||
| Infobox references | ||
Zinc chromate, ZnCrO4, is a chemical compound containing the chromate anion, appearing as odorless yellow solid powder.[2][3][4] It is used industrially in chromate conversion coatings, having been developed by Ford Motor Company in 1920s.[5] Exposure to zinc chromate can cause tissue ulceration and cancer.[1][3]
Its use as a corrosion resistant agent was applied to aluminium alloy parts first in commercial aircraft, and then in military ones. During the 1940 and 1950s it was typically found as the "paint" in the wheel wells of retractable landing gear on U.S. military aircraft, not because of its glaring yellow-green color symbolizing anything, but to protect the aluminium from corrosion.
When used as a pigment, it is known as Zinc Yellow,[2] Buttercup Yellow or Yellow 36.[6] It is rarely used in art any longer due to the degeneration of the pigment into a brown color. This effect can be seen in Georges Seurat's famous painting: A Sunday Afternoon on the Island of La Grande Jatte.[7]
Zinc chromate putty was used as sealant in addition to two O-rings between sections of the failed solid rocket booster on Space Shuttle Challenger. Blowholes in this putty may have been a minor contributor to the loss of the shuttle.[8]
References
- ↑ 1.0 1.1 "OHSA Chemical Sampling Information for Zinc Chromate". Occupational Safety and Health Administration. Retrieved 24 march 2011.
- ↑ 2.0 2.1 National Oceanic and Atmospheric Administration. "ZINC CHROMATE - CAMEO Chemicals". Retrieved 24 March 2011.
- ↑ 3.0 3.1 "OHSA Guideline for Zinc Chromate". Occupational Safety and Health Administration. Retrieved 24 March 2011.
- ↑ Richard P. Pohanish (9 February 2004). HazMat data: for first response, transportation, storage, and security. John Wiley and Sons. p. 1155. ISBN 978-0-471-27328-8. Retrieved 24 March 2011.
- ↑ Waligorski, Martin. "Everything You Need to Know About Zinc Chromate". Retrieved 23 March 2011.
- ↑ "Basic Zinc Chromate". Chemical Land21. Retrieved 24 March 2011.
- ↑ Gage, John (1993). Color and Culture: Practice and Meaning from Antiquity to Abstraction. Boston: Little, Brown. pp. 220, 224..
- ↑ J.A. Hickman (1997). Polymeric Seals and Sealing Technology. iSmithers Rapra Publishing. p. 25. ISBN 978-1-85957-096-8. Retrieved 24 March 2011.
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