Strontium chromate pigment

A trade name for strontium chromate pigments is Strontiumchromat L203S-L203E (SNCZ, France). 

As far as carcinogenic effects are concerned, extensive epidemiological investigations have given no indication that the practically insoluble lead chromate pigments have any carcinogenic properties [3.139, 3.140]. Such properties have been reported for the more soluble zinc chromate and strontium chromate pigments. 

The requirements on strontium chromate pigments are specified in ISO 2040 -Strontium chromate pigments for paints [5.60]. Required characteristics for zinc potassium chromate, zinc tetrahydroxychromate and strontium chromate are summarized in Table 5.4. 

ISO 2040, Strontium chromate pigments for paints, International Organization for Standardization, Switzerland, 1972... 

Pigment yellow 31. See Barium chromate Pigment yellow 32. See Strontium chromate Pigment yellow 33. See Calcium chromate Pigment yellow 36. See Zinc chromate... 

Lalor (1973) Lalor, E. Zinc and Strontium Chromates Pigment Handbook 1 Patton, T.C. (ed.) John Wiley, New York (1973) 847-859... 

Ce(lll) molybdate has shown some promise as a conrosion inhibitor in an epoxy lyamide primer but still does not match the performance of strontium chromate pigmented primers (Ref 23). 

Strontium Chromate. Strontium chromate [7789-06-2] SrCrO, is made by precipitation of a water-soluble chromate solution using a strontium salt or of chromic acid using a strontium hydroxide solution. It has a specific gravity of 3.84 and is used as alow toxicity, yellow pigment and as an anticorrosive primer for zinc, magnesium, alurninum, and alloys used in aircraft manufacture (8) (see Corrosion and corrosion control). 

A primer On metal, the purposes of a primer are to enhance corrosion protection and to give excellent adhesion. The primer will contain anticorrosive pigments, such as strontium chromate or zinc phosphate, which will slowly release ions that can repair damage or faults in the underlying conversion coating. 

The lARC has concluded that there is sufficient evidence in humans for the carcinogenicity of chromium(Vl) compounds as encountered in the chromate production, chromate pigment production, and chromate plating industries. In experimental animals there is sufficient evidence for the carcinogenicity of calcium chromate, zinc chromates, strontium chromate, and lead chromate. ... 

The anticorrosive pigments zinc chromate, zinc tetraoxychromate, and strontium chromate are described in Section 5.2.6... 

Strontium chromate SrCr04 [7789-06-2] strontium chromate A strontium yellow C.I. Pigment Yellow 32 yellow powder ca. 2... 

Lead chromates, lead molybdates, chrome greens, and fast chrome greens are supplied as pigment powders, low-dust or dust-free preparations, or as pastes. The anticorrosive pigments zinc chromate, zinc tetraoxychromate, and strontium chromate are described in Section 5.2.4.2. 

Eor chromate-containing anticorrosive pigments like zinc chromate, zinc potassium chromate, zinc tetraoxichromate and strontium chromate, the TRK value/TLV-TWA value for chromium(VI) compounds of 0.05 mg m calculated as CrOs in total dust has to be complied with [5.111]. 

The European Community classifies lead-containing anticorrosive pigments like Red Lead as well as zinc chromate, zinc potassium chromate, zinc tetraoxichromate, strontium chromate and, since 2000, also zinc phosphate as N, Dangerous for the environment (dead fish / tree) with the risk (R) and safety phrases (S) [5.112] ... 

SYNS CHROMIC ACID, STRONTIUiM SALT (1 1) C.I. PIGMENT YELLOW 32 DEEP LEMON YELLOW STRONTIUM CHROMATE (VI) STRONTIUM CHROMATE 12170 STRONTIUM YELLOW... 

Strontium chromate is used in the following applications as a pigment, as an anticorrosive agent in aluminum and magnesium alloys, in vinyl sheeting, and in chemical-resistant coatings. 

The highest exposures occur occupationally. The National Occupational Hazard Survey conducted by the National Institute for Occupational Safety and Health from 1972 through 1974 concluded that some 2.5 million workers could be exposed to chromium and its compounds in the workplace. The National Occupational Exposure Survey conducted a decade later from 1981 through 1983 estimated a total of almost 200 000 workers were exposed to hexavalent chromium compounds (barium chromate, calcium chromate, chromium trioxide, lead chromate, strontium chromate, and zinc chromate). Occupational exposure occurs primarily from stainless steel production and welding, chromate production, chrome plating, ferrochrome alloys, chrome pigment and tanning industries. 

Hexavalent chromium compounds are classified as substances known to be carcinogenic to humans. This is based upon sufficient evidence of carcinogenicity in humans exposed in chrome production facilities, chromium-alloy facilities, in the chrome plating industry as well as in chrome pigment industries. This exposure results in an increased incidence of lung cancer among these workers. The incidence of cancers at other sites may be increased in these occupational workers There is not sufficient evidence to show that barium chromate, calcium chromate, chromium trioxide, lead chromate, sodium dichromate and strontium chromate are carcinogenic in humans. 

Strontium is fairly reactive and therefore is rarely found in its pure form in the earth s crust. Examples of common strontium compounds include strontium carbonate, strontium chloride, strontium hydroxide, strontium nitrate, strontium oxide, and strontium titanate. The most toxic strontium compound is strontium chromate, which is used in the production of pigments and can cause cancer by the inhalation route. Strontium chromate is not included in the Levels of Significant Exposure (LSE) tables for strontium since the carcinogenic effects of the compound are a function of the concentration of hexavalent chromium, and strontium only contributes to solubility. The Toxicological Profile for Chromium (ATSDR 2000) should be consulted for additional information on the health effects of strontium chromate. 

Anodic passivation of steel surfaces can be efficiently achieved by metal chromates. Chromates of Intermediate solubility (e.g., zinc chromate and strontium chromate) allow a compromise between mobility in the film and leaching from the film to be achieved. Chromates inhibit corrosion in aqueous systems by formation of a passivating oxide film. The effectiveness of chromate inhibitors in aqueous systems depends on the concentration of other ionic species in solution, for example, chloride. Synthetic resin composition can also significantly influence the effectiveness of chromate pigments. The effect appears to be related to the polarity of the resin (20) chromate pigments appear to be less effective in resins of low polarity. 

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