ASTM D1648-86(2003)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D 1648 – 86 (Reapproved 2003)
Standard Specification for
Basic Lead Silicochromate Pigment
This standard is issued under the fixed designation D 1648; 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.
TABLE 1 Requirements for Pigments
1. Scope
Weight %
1.1 This specification covers two types of pigment commer-
Type 1 Type 2
cially known as basic lead silicochromate.
Regular Particle Size Fine Particle Size
1.2 The values stated in SI units are to be regarded as the
Min Max Min Max
standard. The values given in parentheses are for information
Lead oxide (PbO) 46.0 49.0 42.5 46.0
only.
Chromium trioxide (CrO ) 5.1 5.7 6.3 7.2
Silica (SiO ) 45.5 48.5 47.5 50.5
2. Referenced Documents
Moisture and other volatile mat- . 0.2 . 0.2
ter, % . 0.2 . 0.2
2.1 ASTM Standards:
Ignition loss at 450 to
D 1208 Test Methods for Common Properties of Certain
550°C, %
Pigments
D 1366 Practice for Reporting Particle Size Characteristics
of Pigments
retained on a 45-µm (No. 325) sieve shall be less than 0.3 %.
D 1844 Test Methods for Chemical Analysis of Basic Lead
Themaximumspecificsurfacediameter(SSD)shallbe8.5µm.
Silicochromate
3.4.2 Type 2—This grade is characterized by major amounts
E 20 Practice for Particle Size Analysis of Particulate Sub-
of fine-sized particles. In general, the maximum size is
stances in the Range of 0.2 to 75 µm by Optical Micros-
essentially below 1.0 to 2.5 µm. Coarse particles retained on a
copy
45-µm (No. 325) sieve shall be less than 0.1 %. The maximum
Specific Surface Diameter (SSD) shall be 2.0 µm.
3. Composition and Properties
3.4.3 Where closer control within a grade is required, the
3.1 Both types of pigment shall consist of silica coated with
fineness requirements shall be as agreed upon by the purchaser
lead silicates and lead chromates and shall conform to the
and the seller.
requirements in Table 1.
3.2 The mass color and character of the tint obtained by
4. Sampling
mixing the pigment with a white pigment shall be the same as
4.1 Two samples shall be taken at random from different
that of a reference sample mutually agreed upon by the
packages from each lot, batch, day’s pack, or other unit of
purchaser and the seller.
production in a shipment. When no markings distinguishing
3.3 The oil absorption shall be equal, within agreed upon
between units of a production appear, samples shall be taken
tolerances, to that of a reference sample agreed upon by the
from different packages, in the ratio of two samples for each
purchaser and the seller.
5000 kg (10 000 lb), except that for shipments of less than
3.4 Particle Size:
10 000 lb two samples shall be taken. At the option of the
3.4.1 Type 1—This grade is characterized by major
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