ASTM D5723-95
(Practice)Standard Practice for Determination of Chromium Treatment Weight on Metal Substrates by X-Ray Fluorescence
Standard Practice for Determination of Chromium Treatment Weight on Metal Substrates by X-Ray Fluorescence
SCOPE
1.1 This practice covers the use of X-ray fluorescence (XRF) techniques for determination of the coating weight of chromium treatments on metal substrates. These techniques are applicable for determination of the coating weight as chromium or total coating weight of a chromium-containing treatment, or both, on a variety of metal substrates.
1.2 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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Designation: D 5723 – 95
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Practice for
Determination of Chromium Treatment Weight on Metal
Substrates by X-Ray Fluorescence
This standard is issued under the fixed designation D 5723; 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 2.3.2 The coating weight is determined by measurement of
the fluorescent X rays of the coating. The detection system is
1.1 This practice covers the use of X-ray fluorescence
set to count the number of X rays in an energy region that is
(XRF) techniques for determination of the coating weight of
characteristic of X rays from the element of interest. The
chromium treatments on metal substrates. These techniques are
element of interest in this practice is chromium.
applicable for determination of the coating weight as chro-
2.3.3 If a linear relationship exists, the coating weight and
mium or total coating weight of a chromium-containing
number of counts of X rays of a chromium treatment on a
treatment, or both, on a variety of metal substrates.
particular substrate can be expressed by a conversion factor
1.2 This standard does not purport to address all of the
that represents the number of counts for a particular coating
safety concerns, if any, associated with its use. It is the
weight unit/unit area. This is usually expressed in mg/ft or
responsibility of the user of this standard to establish appro-
mg/m of chromium or total coating weight.
priate safety and health practices and determine the applica-
2.3.4 The exact relationship between the measured number
bility of regulatory limitations prior to use.
of counts and corresponding coating weight must be estab-
2. Summary of Practice lished for each individual combination of substrate and
chromium-containing treatment. Usually determined by the
2.1 Excitation—The measurement of chromium treatment
treatment supplier, this relationship is established by using
coating weights by XRF methods is based on the combined
primary standards having known amounts of the same treat-
interaction of the chromium coating and substrate with an
ment applied to the same substrate composition as the speci-
intense beam of primary radiation. Since each element fluo-
mens to be measured.
resces at an energy characteristic of the particular element, this
2.3.5 Some X-ray apparatus have a data handling system
interaction results in the generation of X rays of defined energy.
whereby a coating weight versus X-ray counts curve may be
The primary radiation may be generated by an X-ray tube or
established within the system for the direct readout of coating
derive from a radioisotope.
weight. If such apparatus does not permit the entry of a
2.2 Detection—The secondary beam (fluorescent X rays of
conversion factor as described in 2.3.3, it is calibrated using a
the elements and scattered radiation) is read by a detector that
bare, untreated specimen and a minimum of three specimens
can discriminate between the energy levels of fluorescing
with known coating weights of the treatment and substrate
radiations in the secondary beam. The detection system in-
combination of interest. The coating weight to be measured
cludes the radiation detector with electronics for pulse ampli-
must be within the range of these known coating weights. More
fication and pulse counting.
than three known specimens must be used if the relationship of
2.3 Basic Principle:
X-ray counts to coating weight is not linear over the range to
2.3.1 A relationship exists between the treatment coating
be measured. The treatment supplier should be consulted for
weight and secondary radiation intensity. This relationship is
recommendations for establishing the curve in the instrument
usually linear within the desired coating weights of the
for the particular treatment and substrate combination of
chromium treatments on metal substrates. The measurements
interest.
are based on primary standards of known coating weights and
instrument calibration that correlates the secondary radiation
3. Significance and Use
intensity with the coating weight quantitatively.
3.1 The procedure described in this practice is designed to
provide a method by which the coating weight of chromium
treatments on metal substrates may be determined.
This practice is under the jurisdiction of ASTM Committee D-1 on Paint and
Related Coatings, Materials, and Applications and is the direct responsibility of
3.2 This procedure is applicable for determination of the
Subcommittee D01.53 on Coil Coated Metal.
total coating weight and the chromium coating weight of a
Current edition approved May 15, 1995. Published July 1995.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 5723
chromium-containing treatment. 6.2 Set the instrument settings as follows:
Dial and Arm Chromium Position
4. Apparatus and Materials
Seconds indicator per treatment supplier
Multiplier switch per treatment supplier
4.1 Measuring Instrument, which is capable of determining
Response switch per treatment supplier
the coating weights of chromium-containing treatments on
Range per treatment supplier
Milliamps adjust for calibration of output per treatment supplier
metal substrates by X-ray fluorescence is required. The treat-
ment supplier should be consulted for the suitability of the
6.3 All specimens must be seated firmly and securely over
instrumentation to be used.
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