ASTM D5723-95(2019)

Standard Practice for Determination of Chromium Treatment Weight on Metal Substrates by X-Ray Fluorescence

SIGNIFICANCE AND USE
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.  
3.2 This procedure is applicable for determination of the total coating weight and the chromium coating weight of a chromium-containing treatment.
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Nov-2019
• ICS: 71.040.50 - Physicochemical methods of analysis
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.53 - Coil Coated Metal

Relations

• Replaces: ASTM D5723-95(2015) - Standard Practice for Determination of Chromium Treatment Weight on Metal Substrates by X-Ray Fluorescence
• Effective Date: 01-Dec-2019
• Referred By: ASTM D3794-22 - Standard Guide for Testing Coil Coatings
• Effective Date: 01-Dec-2019
• Referred By: ASTM D6492-99(2022) - Standard Practice for Detection of Hexavalent Chromium On Zinc and Zinc/Aluminum Alloy Coated Steel
• Effective Date: 01-Dec-2019

Overview

ASTM D5723-95(2019) is an international standard developed by ASTM International for determining the weight of chromium treatments applied to metal substrates using X-ray fluorescence (XRF) techniques. This standard provides a standardized practice for measuring both the total coating weight and the chromium-specific coating weight on a variety of metal substrates. It is designed to ensure accuracy and consistency in quality control and material certification in metal finishing industries.

The standard outlines methods by which users can establish relationships between secondary X-ray intensity and coating weight, calibrate instrumentation, prepare specimens, and perform calculations-all critical for reliable XRF-based chromium coating measurement.

Key Topics

• Coating Weight Determination: Focuses on quantifying the mass of chromium-containing treatments on different metal substrates.
• Use of X-Ray Fluorescence (XRF): Explains the principle of detecting and measuring characteristic X-rays emitted from chromium in the coating when exposed to primary X-ray radiation.
• Calibration and Instrumentation: Stresses the importance of calibrating XRF instruments using primary standards of known coating weights and following supplier-specific procedures.
• Specimen Preparation: Details the preparation of both treated and blank (untreated) coupons, including abrasion techniques for creating a suitable blank sample.
• Measurement and Calculation: Outlines procedures for taking multiple readings, calculating average counts, determining the difference (delta counts), and applying conversion factors to compute coating weights precisely.
• Safety and Compliance: Highlights the user's responsibility for adhering to safety, health, and environmental regulations applicable to XRF measurements.

Applications

ASTM D5723-95(2019) is widely applicable in industries where quality assurance of metal products is essential, such as:

• Metal Finishing: For verifying correct application and uniformity of chromium coatings in coil coating and other finishing processes.
• Manufacturing Quality Control: Ensures products meet regulatory and customer specifications for chromium coating thickness and weight.
• Material Certification: Provides reliable data supporting product claims and compliance in sectors like automotive, aerospace, and construction.
• Research and Development: Assists in developing new chromium treatments or testing existing processes for efficacy and durability.

The practice is suitable for a broad range of metal substrates and is adaptable to production, laboratory, or research environments using properly calibrated XRF equipment.

Related Standards

When implementing ASTM D5723-95(2019), consider its relationship with other standards:

• ASTM E1621 - Standard Guide for Elemental Analysis by Wavelength Dispersive X-Ray Fluorescence Spectrometry.
• ASTM B568 - Standard Test Method for Measurement of Coating Thickness by X-Ray Spectrometry.
• ISO 3497 - Metallic coatings - Measurement via X-ray spectrometric methods.

Using ASTM D5723 in conjunction with these standards ensures comprehensive and up-to-date practices for coating verification and elemental analysis, aligning quality procedures with internationally recognized methodologies.

Keywords: chromium coating weight, X-ray fluorescence, XRF analysis, metal substrates, ASTM D5723, surface treatment measurement, coating thickness standard, metal finishing quality control.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D5723 − 95 (Reapproved 2019)
Standard Practice for
Determination of Chromium Treatment Weight on Metal
Substrates by X-Ray Fluorescence
This standard is issued under the fixed designation D5723; 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 2.3.1 A relationship exists between the treatment coating
weight and secondary radiation intensity. This relationship is
1.1 This practice covers the use of X-ray fluorescence
usually linear within the desired coating weights of the
(XRF) techniques for determination of the coating weight of
chromium treatments on metal substrates. The measurements
chromium treatments on metal substrates.These techniques are
are based on primary standards of known coating weights and
applicable for determination of the coating weight as chro-
instrument calibration that correlates the secondary radiation
mium or total coating weight of a chromium-containing
intensity with the coating weight quantitatively.
treatment, or both, on a variety of metal substrates.
2.3.2 The coating weight is determined by measurement of
1.2 This standard does not purport to address all of the
the fluorescent X rays of the coating. The detection system is
safety concerns, if any, associated with its use. It is the
set to count the number of X rays in an energy region that is
responsibility of the user of this standard to establish appro-
characteristic of X rays from the element of interest. The
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. element of interest in this practice is chromium.
1.3 This international standard was developed in accor-
2.3.3 If a linear relationship exists, the coating weight and
dance with internationally recognized principles on standard-
number of counts of X rays of a chromium treatment on a
ization established in the Decision on Principles for the
particular substrate can be expressed by a conversion factor
Development of International Standards, Guides and Recom-
that represents the number of counts for a particular coating
mendations issued by the World Trade Organization Technical
weight unit/unit area. This is usually expressed in mg/ft or
Barriers to Trade (TBT) Committee. 2
mg/m of chromium or total coating weight.
2.3.4 The exact relationship between the measured number
2. Summary of Practice
of counts and corresponding coating weight must be estab-
2.1 Excitation—The measurement of chromium treatment
lished for each individual combination of substrate and
coating weights by XRF methods is based on the combined
chromium-containing treatment. Usually determined by the
interaction of the chromium coating and substrate with an
treatment supplier, this relationship is established by using
intense beam of primary radiation. Since each element fluo-
primary standards having known amounts of the same treat-
resces at an energy characteristic of the particular element, this
ment applied to the same substrate composition as the speci-
interactionresultsinthegenerationofXraysofdefinedenergy.
mens to be measured.
The primary radiation may be generated by an X-ray tube or
2.3.5 Some X-ray apparatus have a data handling system
derive from a radioisotope.
whereby a coating weight versus X-ray counts curve may be
2.2 Detection—The secondary beam (fluorescent X rays of
established within the system for the direct readout of coating
the elements and scattered radiation) is read by a detector that
weight. If such apparatus does not permit the entry of a
can discriminate between the energy levels of fluorescing
conversion factor as described in 2.3.3, it is calibrated using a
radiations in the secondary beam. The detection system in-
bare, untreated specimen and a minimum of three specimens
cludes the radiation detector with electronics for pulse ampli-
with known coating weights of the treatment and substrate
fication and pulse counting.
combination of interest. The coating weight to be measured
2.3 Basic Principle:
mustbewithintherangeoftheseknowncoatingweights.More
than three known specimens must be used if the relationship of
1 X-ray counts to coating weight is not linear over the range to
This practice is under the jurisdiction of ASTM Committee D01 on Paint and
Related Coatings, Materials, and Applications and is the direct responsibility of
be measured. The treatment supplier should be consulted for
Subcommittee D01.53 on Coil Coated Metal.
recommendations for establishing the curve in the instrument
Current edition approved Dec. 1, 2019. Published December 2019. Originally
for the particular treatment and substrate combination of
approved in 1995. Last previous edition approved in 2015 as D5723 – 95 (2015).
DOI: 10.1520/D5723-95R19. interest.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5723 − 95 (2019)
3. Significance and Use 5.4 The coated area of the specimen must be larger than the
measuring area.
3.1 The procedure described in this practice is designed to
provide a method by which the coating weight of chromium
6. Procedure
treatments on metal substrates may be determined.
6.1 Operate the instrument in accordance with the manufac-
3.2 This procedure is applicable for determination of the
turer’s instructions.
total coating weight and the chromium coating weight of a
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
metal substrates by X-ray fluorescence is required. The treat-
Milliamps adjust for calibration of output per treatment
...