ASTM D478-02(2019)

Standard Specification for Zinc Yellow (Zinc Chromate) Pigments

ABSTRACT
This specification covers zinc yellow (zinc chromate) pigments used in rust-inhibiting protective coatings and metal primers for ferrous and non-ferrous metals. The two types of pigments include: Type I and Type II. The pigment shall conform to the required composition for zinc, chromium, sulfates, chlorides, alkaline slats, matter insoluble in acetic acid, moisture and other volatile matter, and coarse particles. The following tests shall be conducted: chemical analysis, coarse particles, and mass color and tinting strength.
SIGNIFICANCE AND USE
3.1 Zinc yellow is used in rust-inhibiting protective coatings and metal primers for ferrous and non-ferrous metals.
SCOPE
1.1 This specification covers the pigments commercially known as zinc yellow (zinc chromate).  
1.2 Two types are included:  
1.2.1 Type I—High-purity, low sulfate and chloride content.  
1.2.2 Type II—Regular grade.  
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-May-2019
• ICS: 87.060.10 - Pigments and extenders
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.31 - Pigment Specifications

Relations

• Replaces: ASTM D478-02(2012) - Standard Specification for Zinc Yellow (Zinc Chromate) Pigments
• Effective Date: 01-Jun-2019
• Refers: ASTM D444-88(2014) - Standard Test Methods for Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate Yellow)
• Effective Date: 01-Dec-2014
• Refers: ASTM D444-88(2008) - Standard Test Methods for Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate Yellow)
• Effective Date: 01-Feb-2008
• Refers: ASTM D387-00(2008) - Standard Test Method for Color and Strength of Chromatic Pigments with a Mechanical Muller
• Effective Date: 01-Feb-2008
• Refers: ASTM D185-07 - Standard Test Methods for Coarse Particles in Pigments
• Effective Date: 01-Jul-2007
• Refers: ASTM D444-88(2003) - Standard Test Methods for Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate Yellow)
• Effective Date: 01-Dec-2003
• Refers: ASTM D387-00 - Standard Test Method for Color and Strength of Chromatic Pigments with a Mechanical Muller
• Effective Date: 10-Jun-2000
• Refers: ASTM D185-84(1999) - Standard Test Methods for Coarse Particles in Pigments, Pastes, and Paints
• Effective Date: 10-May-1999
• Refers: ASTM D444-88(1999) - Standard Test Methods for Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate Yellow)
• Effective Date: 10-May-1999
• Referred By: ASTM D444-88(2020) - Standard Test Methods for Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate Yellow)
• Effective Date: 01-Jun-2019

Overview

ASTM D478-02(2019) - Standard Specification for Zinc Yellow (Zinc Chromate) Pigments outlines requirements for zinc yellow pigments commonly known as zinc chromate. These pigments are primarily used in rust-inhibiting protective coatings and metal primers for ferrous and non-ferrous metals. The specification defines two pigment types, addresses compositional criteria, and details necessary test methods to ensure pigment quality and performance.

Key Topics

• Pigment Types:

  • Type I: High-purity grade with low sulfate and chloride content, suitable for applications requiring enhanced purity.
  • Type II: Regular grade with more flexible limits on sulfate and chloride content.

• Composition Requirements:

  • Specific ranges for zinc (as ZnO), chromium (as CrO₃), sulfates, chlorides, alkaline salts (K₂O), insoluble matter in acetic acid, moisture and volatile matter, and coarse particles.
  • Strict composition adherence ensures pigment performance, color characteristics, and compatibility with coatings.

• Sampling and Testing:

  • Random sampling from production lots to ensure batch consistency.
  • Required tests include chemical analysis, evaluation of coarse particles, mass color, and tinting strength.

• International Standardization:

  • Developed under principles of the World Trade Organization Technical Barriers to Trade (TBT) Committee, supporting global trade and harmonized quality benchmarks.

Applications

Zinc yellow (zinc chromate) pigments specified in ASTM D478-02(2019) are critical in the following applications:

• Rust-Inhibiting Coatings:

  • Formulations for both ferrous and non-ferrous metal surfaces, enhancing corrosion resistance and prolonging component lifespan.

• Metal Primers:

  • Used as a base layer for structural steel, automotive bodies, aerospace components, and industrial machinery.
  • Essential for environments exposed to high humidity, chemical vapors, or saltwater.

• Protective Paints:

  • Employed in infrastructure projects, bridges, and large-scale metal fabrications.
  • Often chosen for their consistent color performance and reliable rust-inhibiting properties across diverse application scenarios.

• Quality Control and Procurement:

  • Manufacturers and suppliers use this standard to ensure product reliability and maintain customer trust.
  • Specifiers and regulators reference the standard for compliance verification in building and manufacturing projects.

Related Standards

Adherence to ASTM D478-02(2019) may require reference to several related standards to ensure comprehensive compliance and performance evaluation:

• ASTM D185: Test Methods for Coarse Particles in Pigments.
• ASTM D387: Test Method for Color and Strength of Chromatic Pigments with a Mechanical Muller.
• ASTM D444: Test Methods for Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate Yellow).

These related documents address detailed pigment testing procedures, analytical methods, and performance evaluations, supporting the broader quality objectives outlined in ASTM D478-02(2019).

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Keywords: zinc yellow, zinc chromate pigments, rust-inhibiting coatings, metal primers, ASTM D478-02, pigment testing, protective coatings standards, corrosion resistance, industrial pigment standards, composition requirements

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:D478 −02 (Reapproved 2019)
Standard Specification for
Zinc Yellow (Zinc Chromate) Pigments
This standard is issued under the fixed designation D478; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 4. Composition and Properties
1.1 This specification covers the pigments commercially
4.1 Dry Pigment—The pigment shall be a reaction precipi-
known as zinc yellow (zinc chromate).
tate of soluble chromates and a suitable zinc compound and
shall be free of extenders, carbonates, and organic color in any
1.2 Two types are included:
form. The pigment shall conform to the requirements for
1.2.1 Type I—High-purity, low sulfate and chloride content.
composition prescribed in Table 1.
1.2.2 Type II—Regular grade.
1.3 The values stated in SI units are to be regarded as
4.2 The mass color and character of the tint and the tinting
standard. The values given in parentheses are for information
strength formed by a mixture with a white pigment shall be
only.
within mutually agreed upon limits of a standard acceptable to
both the purchaser and the seller.
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
5. Sampling
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5.1 Two samples shall be taken at random from different
mendations issued by the World Trade Organization Technical
packages from each lot, batch, day’s pack, or other unit of
Barriers to Trade (TBT) Committee.
production in a shipment. When no markings distinguishing
between units of production appear, samples shall be taken
2. Referenced Documents
2 from different packages in the ratio of two samples for each
2.1 ASTM Standards:
4545 kg (10 000 lb), except that for shipments of less than
D185 Test Methods for Coarse Particles in Pigments
10 000 lb two samples shall be taken. At the option of the
D387 Test Method for Color and Strength of Chromatic
purchaser, the samples may be tested separately or after
Pigments with a Mechanical Muller
blending in equal quantities the samples from the same
D444 Test Methods for Chemical Analysis of Zinc Yellow
production unit to form a composite sample.
Pigment (Zinc Chromate Yellow)
3. Significance and Use
6. Test Methods
3.1 Zinc yellow is used in rust-inhibiting protective coatings
6.1 Tests shall be conducted in accordance with the follow-
and metal primers for ferrous and non-ferrous metals.
ing ASTM test methods:
6.2 Chemical Analysis—Test Methods D444.
This specification is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
6.3 Coarse Particles—Test Methods D185.
Subcommittee D01.31 on Pigm
...