D--Application of paints, primers and specialty coatings containing Strontium Chromate
in the construction of aerospace and aeronautical parts, including aeroplanes / helicopters, spacecraft, satellites, launchers, engines, and for the maintenance of such constructions.
As measurement techniques and test equipment continually improve, routine maintenance detected Strontium Chromate
inside the Environmental Control System of an aircraft.
The primer was pigmented with either strontium chromate
, Type C IES, or titanium dioxide serving as a blank.
was also prepared under controlled conditions by treatment of equimolar K2CrO4 and SrCl2 solution containing some additives, having pH 10 keeping at room temperature for 10 hours.
The results were compared with strontium chromate
and filler material-pigmented coatings.
Zinc chromate and lead chromate are the predominate chromium compounds used in pigments but insoluble barium and strontium chromate
can also be used.
Workers in the 5th Maintenance Squadron identified several areas that were endangering their workers: Strontium Chromate
levels that were 80 times above AFOSH standards; airborne particles that were 50 percent above occupational exposure limits; no sprinkler heads in exhausting ducts which could encourage fire proliferation throughout A/C dock; and inability to check airflow to know when dangerous conditions existed.
Cr(VI) chemicals include: chromium oxide (Cr02) * ammonium dichromate (NH4Cr207) * calcium chromate (CaCr04) * chromium trioxide (chromic acid) (Cr03) * lead chromate (PbCr04) * potassium dichromate (K2Cr207) * sodium chromate (Na2Cr04) * strontium chromate
(SrCr04) * and zinc chromate (Zn_Cr04):
A real life example of how REACH will impact the aerospace industry is the possibility that strontium chromate
may be banned, a chemical used in coatings for aircraft engines to protect against corrosion.
The substances are (1) 1,2-dichloroethane; (2) 2,2'-dichloro-4,4'-methyl-enedianiline; (3) arsenic acid; (4) bis(2-methoxyethyl) ether (diglyme); (5) dichromium tris(chromate); (6) formaldehyde; (7) N,N-dimethylacetamide; (8) pentazinc chromate octahy-droxide; (9) potassium hydroxyoctaoxodizincatedichromate; and (10) strontium chromate
Corrosion inhibitors with hexavalent chrome, such as zinc chromate or strontium chromate
are restricted in use," said Conti.
On aluminium nacelle parts this is replaced by a strontium chromate
based primer formulated for metal components.