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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Most commercially available instruments display the standard deviation directly in units of thickness. It aatm 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.
In no case shall the measurement area be larger than the coated area available on the test specimen. Those that are certi?
With wavelength dispersive systems, the types of detectors commonly used as the gas-? For information on this important aspect, reference should be made to current documents aetm the National Committee on Radiation Protection and Measurement, Federal Register, Nuclear Regulatory Commission, National Institute of Standards and Technology formerly the National Bureau of Standardsand to state and local codes if such exist. It is, therefore, no greater than, and attributable to: To reduce the statistical error to an acceptable level, it is necessary to use a counting interval long enough to accumulate a sufficient number of counts.
Under such circumstances, thickness measurements must be corrected for density differences, unless density differences can be shown to be insigni? Exceptions are allowed if the intensity of the characteristic coating material emission is not in?
If instability is suspected, a series of twenty or more count measurements should be made on the same specimen without moving the specimen and the standard deviation of the series calculated. Therefore, consideration should be given to restricting the radiation to the area of interest by masking or collimation at the radiation source. A superscript epsilon e indicates an editorial change since the last revision or reapproval.
In the curve shown in the Appendix, see Fig. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below. Most modern industrial X-ray instrumentation will perform this calculation automatically.
ASTM B568 (measurement of coating thickness by XRF)
Caution must be exercised, however, to see that the use of a large sample area in conjunction with high power input to the X-ray tube does not result in a signal so large as to exceed the count-rate capacity of the detection system. Current edition approved June 1, 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.
The advantages of radioisotope excitation include more compact instrumentation essentially monochromatic radiation, and very low background intensity. In a suitable detector see 4. X-ray tubes typically have intensities that are several orders of magnitude greater than radioisotope sources. Other disadvantages include the limited number of suitable radioisotopes, their rather short useful lifetimes, and the personnel protection problems associated with highintensity radioactive sources. These should be used only to calibrate and periodically check the condition of the working standards.
The intensity of the emitted secondary X radiation depends, in general, upon the excitation energy, the atomic numbers of the coating and substrate, the area of the specimen exposed to the primary radiation, the power of the X-ray tube, and the thickness of the coating.
Standards representing various thickness ranges of a number of coatings on different substrates are generally available xstm thickness gage manufacturers. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every? An increase in plating thickness results in a larger peak from the plating material and a smaller peak from the base material. Our laboratory also provides laboratory services for plastic testingmetal testingrubber testingoil testingpaint testingplating testingadhesive testingcircuit board testingand other testing.
ASTM B (measurement of coating thickness by XRF) | Eastern Applied Research, Inc.
Precision and Bias 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. Measuring coating thickness was one of the first applications of x-ray fluorescence spectrometry and is still one of the most common uses of the technology.
Calibration standards having the same radius of curvature as that of the test specimens can also be used to eliminate curvature effects. Similarly, the detector may also be masked so that it will see only that area of awtm specimen on which the coating thickness is to be determined. If there is a change of the measured thickness that is large aztm to preclude meeting the requirements of Section 11, recalibrate the instrument. Variations in density can result either bb568 variations in composition or from variations in plating conditions see 6.
The chief advantage of X-ray tube excitation is the high intensity provided. This does not mean that the result would necessarily be ten times as accurate see 7.
In an energydispersive system, the multichannel analyzer is set to accumulate the pulses comprising the same energy peak.