ASTM B – Designation: B – 98 (Reapproved ) UNCONTROLLED (if printed out) Standar. Basic Description: ASTM B X-Ray Fluorescence (XRF) is a non-destructive method of measuring plating thickness by using an X-ray beam to excite the. Designation: B − 98 (Reapproved ) Standard Test Method for This test method is under the jurisdiction of ASTM Committee B08 on Metallic.
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The precision rapidly becomes poorer in the portion of the curve above approximately 10? Such measurements require unique data processing for each multilayer combination to separate the various characteristic emissions involved, to account for the absorption by intermediate layers, and to allow for any secondary excitation which may occur between layers. If the coating on the standard is gold, but not electroplated under conditions known to be the same as the coating being measured, the X-ray properties may be assumed to be the same for mass per unit area measurements.
Variations in density can result either from variations in composition or from variations in plating conditions see 6.
The SRM shall be measured? Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters.
It is necessary, therefore, to have a means of separating the desired components so that their intensities can be measured. This means that during a? The measurement of a coating thickness by X-ray absorption is not applicable if an intermediate coating is present because of the indeterminate absorption effect of intermediate layer.
In no case shall the measurement area be larger than the coated area available on the test specimen. Calibrate it in accordance with Section 7.
The relationship between these units is as follows: It also provides an overview of calibration techniques and best practices along with standard-less fundamental parameters calibrations. Eastern Applied associates are available to help with safety radiation related questions and training if needed.
However, when thickness measurements are made by the X-ray absorption method the substrate composition of the test specimens must be the same as that of the standards. This is on the order of 35 to 50 kV for most thickness-measurement applications. So, the wstm of analyzer certifications that Eastern Applied Research xstm provide are for coating thickness applications and those certifications actually reference the ASTM Standard B This method can be used when the energies of the detected characteristic radiations do not differ sufficiently for example, characteristic radiation from Au and Br.
Calibration standards having the same radius of curvature as that of the test specimens can also be asttm to eliminate curvature effects. Typically, a channel may represent a span of 20 eV for a lithium-drifted silicon detector or to eV for a proportional counter. This standard less measurement shall be corrected by means of calibration standards.
Some forms of instability become evident if the same specimen astk measured periodically. To understand the signi? Care must be taken that the coating and substrate are thick enough aztm prevent the primary X-ray beam from reaching and?
Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. Similarly, the detector may also be masked so that it will see only that area of the specimen on which the coating thickness is to be determined. From six to sixty adjacent channels can be used to store the pulses representing a selected characteristic emission of aetm element, the number of channels depending on the width of the emission peak usually displayed on the face of a cathode ray tube.
ASTM B568 (measurement of coating thickness by XRF)
Typical examples of such combinations are gold on nickel on copper astmm nickel on copper on steel. With wavelength dispersive systems, the types of detectors commonly used as the gas-? Our laboratory also provides laboratory services for plastic testingmetal testingrubber testingoil testingpaint testingplating testingadhesive testingcircuit board testingand other testing. These limiting thicknesses are, in general, different for each coating material.
ASTM B – 98 Standard Test Method for Measurement of Coating Thickness by X-Ray Spectrometry
The intensity of the characteristic silver emission is not in? Those that are certi? However, the ASTM B standard also details some variables that an operator may not think of; such as sample curvature, substrate composition, and surface cleanliness. Results are reported in a table with five or more readings per sample.
If not, make sure that the calibration has been awtm with a substrate having the same thickness and emission properties as the test specimens. However, if the method is based on intensity ratios rather than absolute intensities, minor variations in excitation energy are compensated for.
The corresponding standard deviation in the thickness measurement is a function of the slope of the calibration curve at the point of measurement. Precision and Bias Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may g568.
In the curve n568 in the Appendix, see Fig. Therefore, in any method based on a simple relationship between intensity and thickness, the?
It must be established experimentally that the minimum thickness requirements have been met for a particular substrate-source combination, although it is sometimes possible to back up the test specimen substrates with a sufficient thickness of materials of the same composition.
This standard has been approved for use by agencies of the Department of Defense. In general, the radiation intensity varies directly with the current and the square of the potential.
If the average of the? Published data in tabular form are available that relate spectrogoniometer settings to the characteristic emissions of elements for each of the commonly used analyzing crystals. Originally approved in Thus, would give a standard deviation indicating 10 times the precision asmt the standard deviation obtained from counts.
The sources of error will be eliminated by the use of calibration standards electroplated in the same type of solution under the same conditions as those used in the production of the coatings to be b658 Copyright by ASTM Int’l all rights reserved ; Reproduction authorized per License Agreement with Victoria Boyer ; Wed Mar 23 Ideally, the exciting radiation is slightly more energetic shorter in wavelength than the astk characteristic X rays.
It is important to note that ASTM B does not detail safety procedures relating to operation of x-ray spectrometry and refers the reader to the appropriate governing bodies and regulations. The advantages of radioisotope excitation include more compact instrumentation essentially monochromatic radiation, and very low background intensity.
This does not mean that the result would necessarily be ten times as accurate see 7. A minimum area of 0. Spatial relationships between the curved surface, the excitation beam, and the detector are particularly important, and variations in these relationships can introduce errors in measurement.