Zinc chromate

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Zinc chromate
Identifiers
CAS number 13530-65-9 YesY
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
NFPA 704.svg
0
2
0
OX
U.S. Permissible
exposure limit (PEL)
0.1 mg/m3[1]
LD50 0.5 to 5 g/kg
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
B-25 Mitchell bombers, painted with Zinc Chromate undercoat, being assembled, 1942

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 anymore.

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, contributing to the loss of the shuttle.[7]

[edit] References


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