Overview
ISO 2068:1972 - "Barium chromate pigments for paints" defines the requirements and test methods for pigments of approximate composition BaCrO4 intended for use in paints and corrosion‑protecting coatings. The standard sets chemical, physical and analytical criteria and references general pigment test methods and sampling procedures to ensure consistent quality and suitability for paint manufacture and anticorrosive applications.
Key Topics
- Scope and composition
- Applies to pigments based on barium chromate (BaCrO4) used in paints and corrosion‑protecting coatings.
- Sampling
- Representative sampling must be carried out in accordance with ISO/R 842 (sampling of raw materials for paints and varnishes).
- Required characteristics and limits
- Soluble nitrates: specified limit - max. 0.1% (as NO3) (see clause 5.3.3 / 5.3.4).
- Soluble chromates: max. 0.01 g CrO3 per 100 ml (for 10 g pigment) (clause 5.3.5).
- Volatile matter (loss on drying): max. 1.0% at 105 °C.
- Sieve residue (63 μm): max. 0.3%.
- Oil absorption: to be agreed between parties and the sample value must be within ±15% of the agreed value.
- (The standard also sets limits and methods for soluble chlorides and additional parameters; see clauses 5.3.2–5.3.5.)
- Test methods and analytical techniques
- Chemical titrations (iodide/thiosulfate, silver nitrate), gravimetric procedures, calcination, distillation, and spectrophotometric colorimetric determinations are specified for measuring Ba, chromates, chlorides and nitrates.
- References to ISO/R 787 for general pigment test parts are included.
Applications
- Ensures consistent quality control of barium chromate pigments used by:
- Pigment manufacturers (production specification and batch testing)
- Paint and coating formulators (raw‑material acceptance)
- Quality assurance laboratories (conformance testing)
- Procurement/specifiers setting contractual requirements for anticorrosive paints
- Particularly relevant where corrosion protection performance and chemical purity (low soluble chromates/nitrates/chlorides) are critical to coating performance.
Related Standards (in ISO 2068:1972)
- ISO/R 787 - General methods of pigment testing (referenced parts for specific tests)
- ISO/R 842 - Sampling of raw materials for paints and varnishes
For detailed test procedures and clause‑level limits, consult the full ISO 2068:1972 document and the referenced ISO/R methods when specifying or testing barium chromate pigments.