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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This is on the order of 35 to 50 kV for most thickness-measurement applications.
The benefit to operators is that it details the variations in x-ray spectrometry systems and explains how XRF works with some terminology that may be useful. This means that during a? If the standards are visibly scratched or abraded they should be replaced. An increase in plating thickness results in a larger peak from the plating material and a smaller peak from the base material.
ASTM B – PLATING THICKNESS BY XRF TESTING SERVICES
The typical relationship between a coating thickness and the intensity of a characteristic emission from the coating metal is illustrated by the curve in the Astmm, Fig.
Material testing you can trust since Eastern Applied associates are available to help asym safety radiation related questions and training if needed.
Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm. Standards of known thickness are required to generate a calibration curve for each plating and base material combination.
Suitable means must be provided to perfectly align the test specimen relative to the excitation beam. Under such circumstances, b5568 measurements must be corrected for density differences, unless density differences can be shown to be insigni? This error is independent of other sources of error such as those arising from mistakes on the part of the operator or from the use of inaccurate standards. The chief advantage of X-ray tube excitation is the high intensity provided.
Calibration standards having the same radius of curvature as that of the test specimens can also be used to eliminate curvature effects. Calibration standards for gold coatings, certi? The instrument calibration may be made with standards of silver on nickel.
If the coating of the standards is electrodeposited from the same bath and under the same conditions as the coating to be measured, the X-ray properties may be assumed to be the same.
X-ray tubes typically have h568 that n568 several orders of magnitude h568 than radioisotope sources. Each element emits energy at a different wavelength so the plating and base material show separate peaks in the XRF spectrum. 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 b586 own responsibility. In no case shall the measurement area be larger than the coated area available on the test specimen.
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. This type of detector is maintained at a very low temperature in a liquid-nitrogen cryostat 77K.
The value should not be signi? Acceptable energy resolution for most thickness measurement requirements can be realized with proportional counters, and these detectors are being used on most of the commercially available thickness gages based on X-ray spectrometry.
The advantages of radioisotope excitation include more compact instrumentation xstm monochromatic radiation, and very low background intensity. These limiting thicknesses are, in general, different for each coating material.
ASTM B568 (measurement of coating thickness by XRF)
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. Care must be taken that the coating and substrate are thick enough to prevent the primary X-ray beam from reaching and? Most modern industrial X-ray instrumentation will perform this calculation automatically.
It is, therefore, no greater than, and attributable to: Cannot measure elements with an atomic weight less than that of calcium. B5568 B X-Ray Fluorescence XRF is a non-destructive method of measuring plating thickness by using an X-ray beam to excite the surface of a n568 and then calculating the intensity of the energy returned by the plating versus the base material. It is possible to correct for dead-time losses. The precision rapidly becomes poorer in the portion of the curve above approximately 10?
In those cases where the measurement of thickness on curved surfaces cannot be avoided, a collimator should be used on v568 excitation beam, reducing the measurement area to asstm size that will minimize the effects of curvature.