ASTM D6280-98(2008)
(Specification)Standard Specification for Zinc Phosphate Pigments
Standard Specification for Zinc Phosphate Pigments
ABSTRACT
This specification covers three types of pigments commercially known as zinc phosphate each of which may or may not be available in specific grades delineated by particle size or oil absorption. The following types of pigments are: Type I which is zinc phosphate, dihydrate predominant, Type II which is zinc phosphate, dihydrate tetrahydrate mixture, and Type III which is zinc phosphate, tetrahydrate predominant. Zinc phosphate functions as both a chemical and a pigment. As a pigment it is used in a variety of applications including that of corrosion inhibiting paints. The pigments shall be subjected to the following tests: specific gravity test, oil absorption test, Hegman grind test, coarse particles test, pH test, specific resistance test, moisture test, and loss on ignition test.
SCOPE
1.1 This specification covers three types of pigments commercially known as zinc phosphate each of which may or may not be available in specific grades delineated by particle size or oil absorption.
1.1.1 Type I—Zinc Phosphate, dihydrate predominant.
1.1.2 Type II—Zinc Phosphate, dihydrate tetrahydrate mixture.
1.1.3 Type III—Zinc Phosphate, tetrahydrate predominant.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D6280 −98(Reapproved2008)
Standard Specification for
Zinc Phosphate Pigments
This standard is issued under the fixed designation D6280; 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.
1. Scope 4. Composition and Properties
1.1 This specification covers three types of pigments com- 4.1 Zinc phosphate pigment is a white corrosion inhibiting
mercially known as zinc phosphate each of which may or may pigment consisting either predominately of zinc phosphate
not be available in specific grades delineated by particle size or dihydrate (Zn (PO ) ·2H O) or a mixture of zinc phosphate
3 4 2 2
oil absorption. dihydrate and zinc phosphate tetrahydrate (Zn (PO ) ·4H O)
3 4 2 2
1.1.1 Type I—Zinc Phosphate, dihydrate predominant. or predominately of zinc phosphate tetrahydrate which is free
1.1.2 Type II—Zinc Phosphate, dihydrate tetrahydrate mix- from extenders, diluents, and other pigments.
ture.
4.2 Zinc phosphate shall be a chemically prepared pigment
1.1.3 Type III—Zinc Phosphate, tetrahydrate predominant.
and shall be of such type and grade as to conform to the
1.2 The values stated in SI units are to be regarded as requirements prescribed in Table 1. They shall additionally be
standard. No other units of measurement are included in this free of extenders, modifiers, diluents, alteration of stoichiomet-
standard. ric chemical structure, co-reacted precipitates, and carbona-
ceous material.
2. Referenced Documents
4.3 The desired properties of the pigment, other than as
2.1 ASTM Standards:
herein indicated, shall be subject to mutual agreement between
D153 Test Methods for Specific Gravity of Pigments
interested parties and shall be based upon a satisfactory match
D185 Test Methods for Coarse Particles in Pigments
between any submitted sample and a previously agreed upon
D280 Test Methods for Hygroscopic Moisture (and Other
reference sample.
Matter Volatile Under the Test Conditions) in Pigments
D281 Test Method for Oil Absorption of Pigments by
5. Classification
Spatula Rub-out
5.1 TypeI—which consists predominately of zinc phosphate
D1193 Specification for Reagent Water
dihydrate (Zn (PO ) ·2H O) and exhibits a differentiating loss
3 4 2 2
D1208 Test Methods for Common Properties of Certain
on ignition of the dried pigment at 600°C between 8.5 and 10.0
Pigments
weight %.
D1210 Test Method for Fineness of Dispersion of Pigment-
5.2 Type II—which consists essentially of a mixture of zinc
Vehicle Systems by Hegman-Type Gage
phosphate dihydrate (Zn (PO ) ·2H O) and Zinc Phosphate
D2448 Test Method for Water-Soluble Salts in Pigments by
3 4 2 2
Tetrahydrate (Zn (PO ) ·4H O) and exhibits a differentiating
Measuring the Specific Resistance of the Leachate of the
3 4 2 2
loss on ignition of the dried pigment at 600°C between 10.0
Pigment
and 14.0 weight %.
3. Significance and Use
5.3 Type III—which consists predominately of zinc phos-
3.1 Zinc phosphate functions as both a chemical and a
phate tetrahydrate (Zn (PO ) ·4H O) and exhibits a differenti-
3 4 2 2
pigment. As a pigment it is used in a variety of applications
ating loss on ignition of the dried pigment at 600°C between
including that of corrosion inhibiting paints.
14.0 and 18.0 weight %.
6. Sampling
This specification is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
6.1 Two samples shall be taken at random from different
Subcommittee D01.31 on Pigment Specifications.
packages from each lot, batch, days pack or other unit of
Current edition approved Nov. 1, 2008. Published November 2008. Originally
production in a shipment. When no markings distinguishing
approved in 1998. Last previous edition approved in 2003 as D6280 – 98 (2003).
DOI: 10.1520/D6280-98R08.
between units of production appear, samples shall be taken
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
from different packages in ratio of two samples for each 5000
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
kg, except for those shipments of less than 5000 kg where two
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. samples shall be taken.At the option of the interested party the
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D6280−98(2008)
TABLE 1 Zinc Phosphate Pigment Properties
Property TYPE I TYPE II TYPE III
ZnO, weight percent 62.6 - 65.1 62.6 - 65.1 62.6 - 65.1
(on ignited sample)
P O , weight percent 34.9 - 37.4 34.9 - 37.4 34.9 - 37.4
2 5
(on ignited sample)
Loss on ignition, weight 8.5 - 10.0 10.0 - 14.0 14.0 - 18.0
percent (of dried pigment)
GRADE GRADE GRADE
Mean Particle Size F M C F M C F M C
(microns) < 2.5 2.5-5.0 > 5.0 same same
Oil adsorption > 30 30 - 15 < 15 same same
Matter soluble in water, 6500 6500 6500
specific resistance,
(min. ohm - cm)
Moisture and other volatile 0.5 0.5 0.5
matter (105 - 110°C)
Specific gravity, g/cm 3.0 - 3.5 3.0 - 3.5 3.0 - 3.5
Hegman grind 6 min 6 min 6 min
Coarse particle
percent residue 325 M (45 0.5 max 0.5 max 0.5 max
µm)
pH, aqueous suspension 6 - 8 6 - 8 6 - 8
samples may be tested separately or as a composite sample 7.1.4 Coarse Particles—Test Methods D185.
formed by blending in equal quantities the samples from the
7.1.5 pH—Test Methods D1208.
same unit of production.
7.1.6 Specific Resistance—Test Method D2448.
7.1.7 Moisture—Test Methods D280.
7. Test Methods
7.1.8 ChemicalAnalysis—Incorporated in this specification
7.1 Tests shall be conducted in accordance with the follow-
as Annex A1 and Annex A2.
ingtestmethods.Testproceduresnotincorporatedhereandnot
7.1.9 Loss on Ignition—Incorporated in this specification as
covered byASTM test methods shall be mutually agreed upon
Annex A3.
between the interested parties.
7.1.1 Specific Gravity—Test Methods D153, Method B.
8. Keywords
7.1.2 Oil Absorption—Test Method D281.
7.1.3 Hegman Grind—Test Method D1210. 8.1 analytical; zinc; zinc phosphate
ANNEXES
(Mandatory Information)
A1. TEST METHOD FOR DETERMINATION OF ZINC CONTENT FOR ZINC PHOSPHATE TYPE PIGMENTS
A1.1 Scope responsibility of whoever uses this standard to consult and
establish the appropriate safety and health practices and
A1.1.1 This test method covers the determination of the
determine the applicability of regulatory limitations prior to
zinc content for zinc phosphate monohydrate, dihydrate, tetra-
use.
hydrate, or mixtures of these various crystal water content
pigments.
A1.2 Reference Documents
A1.1.2 This standard does not purport to address all the A1.2.1 ASTM Standards: Test Method for Determination of
safety concerns, if any, associated with its use. It is the Loss on Ignition for Zinc Phosphate Type Pigments
D6280−98(2008)
D1193 Specification for Reagent Water you can weigh up approximately 4.0 g of ZnO, create the
solution, and standardize it using the primary standard grade
A1.3 Summary of Test Method
ZnO.)
A1.3.1 A weighed sample taken from Annex A3, Test
A1.5.6 0.2 N Disodium Ethylendiaminetetraacetate Dihy-
Method for Determination of Loss on Ignition for Zinc
drate (EDTA)—37.2 g of EDTA per litre of aqueous solution.
Phosphate Type Pigments completed analysis (that is, sample
A1.6 Procedure
contains no associated crystal water), is dissolved in ammonia
buffer, complexed with disodium ethylendiaminetetraacetate
A1.6.1 Weigh approximately 0.25 g (see Annex A3)in
dihydrate (EDTA) and back titrated with a standard zinc
duplicate to the nearest 0.1 mg. Place in respective Erlenmeyer
solution to an eriochrome black T endpoint where the percent
flasks. Add 25 mL of the pH 10 buffer solution. Stir gently to
ZnO is determined.
dissolve. Pipet 50.00 mL of the EDTA solution into each
respective Erlenmeyer flask. Dilute to 200 mL with dionized
A1.4 Significance and Use
water.Add6to7dropsoferiochromeBlackTindicator.Titrate
A1.4.1 This test method provides a reliable means for with the 0.2 N ZnO solution to a wine - red endpoint. Run a
determination of the percent ZnO for zinc phosphate pigments.
blank by titrating 50.00 mL EDTAcontaining 25 mL of pH 10
The percent ZnO content for the product gives evidence of the buffer solution with the 0.2 N ZnO solution.
chemical purity of the pigment.
A1.7 Calculations
A1.5 Reagents and Materials
A1.7.1 Calculate the percent ZnO as follows:
A1.5.1 Purity of Reagents—Reagent grade chemicals shall
V 2V 3N ZnO 34.069
~ !
b s
% ZnO 5 (A1.1)
be used in this test, unless otherwise indicated. It is intended
Mass of Sample
that all reagents shall conform to the specifications of the
where:
Committee on Analytical Reagents of the American Chemical
V = ZnO for blank, mL,
Society, where such specifications a
...
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