Standard Test Method for Ratio of Anatase to Rutile in Titanium Dioxide Pigments by X-Ray Diffraction

SIGNIFICANCE AND USE
This test method is used by titanium dioxide pigment manufacturers and users for process control and product acceptance.
SCOPE
1.1 This test method covers the determination of the ratio of anatase to rutile in titanium dioxide pigments. The method is also applicable to pigment mixtures and pigmented coatings containing titanium dioxide.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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Status
Historical
Publication Date
30-Jun-2005
Current Stage
Ref Project

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ASTM D3720-90(2005) - Standard Test Method for Ratio of Anatase to Rutile in Titanium Dioxide Pigments by X-Ray Diffraction
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D3720–90(Reapproved2005)
Standard Test Method for
Ratio of Anatase to Rutile in Titanium Dioxide Pigments by
X-Ray Diffraction
This standard is issued under the fixed designation D3720; 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 upon the amount of that substance in the mixture. To a minor
extentthepeakintensityofthecomponentisalsodependenton
1.1 This test method covers the determination of the ratio of
the mass absorption coefficient of other materials present.
anatase to rutile in titanium dioxide pigments. The method is
Since the test method utilizes the ratio of the intensities of
also applicable to pigment mixtures and pigmented coatings
diffraction peaks of two chemically similar materials, it is
containing titanium dioxide.
expected that the effects of other constituents will be the same
1.2 The values stated in SI units are to be regarded as the
for both materials.
standard. The values given in parentheses are for information
3.2 The intensity of the diffraction maxima for anatase and
only.
rutile is measured by X-ray diffractometry. The intensity of the
1.3 This standard does not purport to address all of the
anatase peak is converted to anatase content relative to rutile
safety concerns, if any, associated with its use. It is the
and the rutile content is determined by difference.
responsibility of the user of this standard to establish appro-
3.3 The X-ray diffraction measurement is made on single
priate safety and health practices and determine the applica-
pigments, pigment mixtures, films of pigmented coatings, and
bility of regulatory limitations prior to use.
films prepared from liquid coatings, if interfering materials are
2. Referenced Documents
not present. When interfering materials are present, the pig-
ment is separated from the redissolved (or ignited film, or from
2.1 ASTM Standards:
the liquid coating and treated to isolate the titanium dioxide.
D215 Practice for the Chemical Analysis of White Linseed
Oil Paints
4. Significance and Use
D2371 Test Method for Pigment Content of Solvent-
4.1 This test method is used by titanium dioxide pigment
Reducible Paints
manufacturers and users for process control and product
D2698 Test Method for Determination of the Pigment
acceptance.
Content of Solvent-Reducible Paints by High-Speed Cen-
trifuging
5. Interferences
D3925 Practice for Sampling Liquid Paints and Related
5.1 Calcium sulfate interferes, but its effect is eliminated by
Pigmented Coatings
chemical removal (see Practice D215). It is desirable to assure
3. Summary of Test Method by analysis that any residual CaSO is considerably less than
the level of anatase being sought. The insoluble residue after
3.1 TheX-raydiffractionpatternobtainedfromamaterialis
removal of calcium sulfate should be ignited above 700°C.
characteristic of that material. The intensity of a diffraction
Chrome yellow and the valentinite form of antimony trioxide
peak entirely due to one component of a mixture is dependent
also interfere if not removed. High amounts of iron render
analysis difficult due to increased background (see Note 1).
This test method is under the jurisdiction of ASTM Committee D01 on Paint
Additives, such as antimony and zinc, and impurities, such as
and Related Coatings, Materials, andApplications and is the direct responsibility of
niobium and zirconium, are generally present in solid solution
Subcommittee D01.31 on Pigment Specifications.
and thus would not have interfering diffraction peaks. Surface
Current edition approved July 1, 2005. Published August 2005. Originally
approved in 1978. Last previous edition approved in 1999 as D3720 - 90 (1999).
treatments such as silica and alumina do not interfere. Extreme
DOI: 10.1520/D3720-90R05.
differences in particle size between the anatase and rutile
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
portions affect the results.
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
NOTE 1—Backgroundscatterduetohighironlevelsinasamplemaybe
the ASTM website.
3 reduced by use of a cobalt or molybdenum target tube in place of the
Withdrawn. The last approved version of this historical standard is referenced
copper target tube. The background may be eliminated for all practical
on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3720–90 (2005)
purposes by use of a curved crystal monochromator equipped with a
8. Hazards
graphite crystal in conjunction with a copper target tube.
8.1 X-ray producing equipment can be dangerous to both
5.2 In the calculation of converting the ratio to percent it is
theoperatorandpersonsintheimmediatevicinityunlesssafety
implicitly assumed that the sum of anatase and rutile is 100 %,
precautions are strictly observed. Refer to the manufacturer’s
an assumption normally made in TiO pigment systems. Other
2 instruction manual. Exposure to excessive quantities of
materials present would interfere to the extent that they dilute
X-radiation may be injurious to health.Therefore, users should
the sample. The third polymorphic form of TiO , brookite,
2 avoid exposing any parts of their bodies, not only to the direct
would have such an effect. However, it reportedly does not
beam, but also to secondary or scattered radiation that occurs
occur in commercial titanium dioxide pigments.
when an X-ray beam strikes or has passed through any
material. It is strongly recommended that users check the
6. Apparatus
degree of exposure by film carried on them or by the use of
6.1 X-Ray Diffractometer—The principle components of
dosimeters and that blood counts be made periodically. Before
thisinstrumentare:(a)X-raygenerator,(b)coppertargetX-ray
utilizing the equipment, all persons designated or authorized to
tube, (c) goniometer, (d) detector, (e) electronic circuit panel,
operate X-ray instrumentation or supervise its operation,
(f) computer (if used), and (g) strip chart recorder or printer.
should have a full understanding of its nature and should also
6.2 Operating Conditions—The X-ray tube voltage and
become familiar with established safe exposure factors by a
filament current and other settings are selected to record X-ray
careful study of the National Bureau of Standards Handbook
diffraction peaks of weak intensities.
“X-Ray Recommendations of the International Roentgen Ray
6.2.1 Nickel Filter, to remove Cu K beta radiation if a
Committee on X-Ray Protection” and other standard publica-
monochromator is not used. Cu K beta radiation will produce
tions on the subject. Inquiries should be made of state agencies
a diffraction line from the rutile phase of TiO that appears at
as to existing requirements.
the same 2u angle as the anatase analytical line.
6.3 Typical Apparatus Conditions:
9. Specimen Preparation
6.3.1 High-Voltage Power Supply—Select X-ray tube volt-
9.1 Powder Samples:
age, filament current, and other settings so that 0.1 % anatase
9.1.1 Packing the specimen in the specimen holder to obtain
generates a signal with intensity at least four times the noise
a planar surface is one of the most important phas
...

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