ASTM D6280-98(2003)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D 6280 – 98 (Reapproved 2003)
Standard Specification for
Zinc Phosphate Pigments
This standard is issued under the fixed designation D 6280; 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 (e) 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 the requirements prescribed in Table 1. They shall additionally be
standard. The values given in parentheses are for information free of extenders, modifiers, diluents, alteration of stoichiomet-
only. ric chemical structure, co-reacted precipitates, and carbon-
aceous 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
D 153 Test Methods for Specific Gravity of Pigments interested parties and shall be based upon a satisfactory match
D 185 Test Methods for Coarse Particles in Pigments,
between any submitted sample and a previously agreed upon
Pastes, and Paints reference sample.
D 280 Test Methods for Hygroscopic Moisture (and Other
5. Classification
Matter Volatile Under the Test Conditions) in Pigments
D 281 Test Method for Oil Absorption of Pigments by 5.1 TypeI—whichconsistspredominatelyofzincphosphate
Spatula Rub-out dihydrate (Zn (PO ) ·2H O) and exhibits a differentiating loss
3 4 2 2
D 1208 Test Methods for Common Properties of Certain onignitionofthedriedpigmentat600°Cbetween8.5and10.0
Pigments weight %.
D 1210 TestMethodforFinenessofDispersionofPigment- 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
3 4 2 2
D 2448 TestMethodforWater-SolubleSaltsinPigmentsby Tetrahydrate (Zn (PO ) ·4H O) and exhibits a differentiating
3 4 2 2
Measuring the Specific Resistance of the Leachate of the loss on ignition of the dried pigment at 600 °C between 10.0
Pigment and 14.0 weight %.
5.3 Type III—which consists predominately of zinc phos-
3. Significance and Use
phate tetrahydrate (Zn (PO ) ·4H O) and exhibits a differenti-
3 4 2 2
3.1 Zinc phosphate functions as both a chemical and a ating loss on ignition of the dried pigment at 600 °C between
pigment. As a pigment it is used in a variety of applications
14.0 and 18.0 weight %.
including that of corrosion inhibiting paints.
6. Sampling
6.1 Two samples shall be taken at random from different
This specification is under the jurisdiction of ASTM Committee D01 on Paint
packages from each lot, batch, days pack or other unit of
and Related Coatings, Materials, andApplications and is the direct responsibility of
production in a shipment. When no markings distinguishing
Subcommittee D01.31 on Pigment Specifications.
Current edition approved Dec. 1, 2003. Published December 2003. Originally
between units of production appear, samples shall be taken
approved in 1998. Last previous edition approved in 1998 as D 6280 – 98.
from different packages in ratio of two samples for each 5000
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
kg, except for those shipments of less than 5000 kg where two
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on samples shall be taken.At the option of the interested party the
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 6280 – 98 (2003)
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 D 185.
formed by blending in equal quantities the samples from the
7.1.5 pH—Test Methods D 1208.
same unit of production.
7.1.6 Specific Resistance—Test Method D 2448.
7.1.7 Moisture—Test Methods D 280.
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 D 153, Method B.
8. Keywords
7.1.2 Oil Absorption—Test Method D 281.
7.1.3 Hegman Grind—Test Method D 1210. 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 establish the appropriate safety and health practices and
determine the applicability of regulatory limitations prior to
A1.1.1 This test method covers the determination of the
use.
zinc content for zinc phosphate monohydrate, dihydrate, tet-
rahydrate, or mixtures of these various crystal water content
A1.2 Reference Documents
pigments.
A1.1.2 This standard does not purport to address all the A1.2.1 ASTM Standards:
safety concerns, if any, associated with its use. It is the Test Method for Determination of Loss on Ignition for Zinc
responsibility of whoever uses this standard to consult and Phosphate Type Pigments
D 6280 – 98 (2003)
D 1193 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
A1.6.1 Weigh approximately 0.25 g (see Annex A3)in
buffer, complexed with disodium ethylendiaminetetraacetate
duplicate to the nearest 0.1 mg. Place in respective Erlenmeyer
dihydrate (EDTA) and back titrated with a standard zinc
flasks. Add 25 mL of the pH 10 buffer solution. Stir gently to
solution to an eriochrome black T endpoint where the percent
dissolve. Pipet 50.00 mL of the EDTA solution into each
ZnO is determined.
respective Erlenmeyer flask. Dilute to 200 mL with dionized
A1.4 Significance and Use
water.Add6to7dropsoferiochromeBlackTindicator.Titrate
with the 0.2 N ZnO solution to a wine - red endpoint. Run a
A1.4.1 This test method provides a reliable means for
blank by titrating 50.00 mL EDTAcontaining 25 mL of pH 10
determination of the percent ZnO for zinc phosphate pigments.
buffer solution with the 0.2 N ZnO solution.
The percent ZnO content for the product gives evidence of the
chemical purity of the pigment.
A1.7 Calculations
A1.7.1 Calculate the percent ZnO as follows:
A1.5 Reagents and Materials
~V –V ! 3N ZnO 3 4.069
A1.5.1 Purity of Reagents—Reagent grade chemicals shall
b s
% ZnO 5 (A1.1)
Mass of Sample
be used in this test, unless otherwise indicated. It is intended
that all reagents shall conform to the specifications of the
where:
Committee on Analytical Reagents of the American Chemical
V = ZnO for blank, m
...