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.
|Published (Last):||14 October 2012|
|PDF File Size:||17.37 Mb|
|ePub File Size:||14.86 Mb|
|Price:||Free* [*Free Regsitration Required]|
This is on the order of 35 to 50 kV for most thickness-measurement applications.
Avoid specimen areas having visible defects such as? This industry standard ASTM B should be reviewed by all operators of x-ray fluorescence because it offers a b68 overview and highlights proper implementation of the technology. Exceptions are allowed if the intensity of the characteristic coating material emission is not in? Instrument measurement precision will rapidly decrease with increasing thickness in the hyperbolic range.
Measuring coating thickness was one of the first applications of x-ray fluorescence spectrometry and is still one of the axtm common uses of the technology.
Results are reported in a table with five or more readings per sample. Therefore, in any method based on a simple relationship between intensity and thickness, the? The typical relationship between coating thickness and the intensity of a characteristic emission from the substrate is shown in the Appendix, see Fig. 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.
A superscript epsilon e indicates an editorial change since the last revision or reapproval. The measuring methods permit the simultaneous measurement of coating systems with up to three layers. The situation is similar for b5688 absorption curve shown in the Appendix, see Fig.
ASTM B – PLATING THICKNESS BY XRF TESTING SERVICES
The corresponding standard deviation in the thickness measurement is a function of the slope of the calibration curve at the point of measurement. 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. The intensities are background-corrected, that is, the intensity for Ni Ka is obtained from a sample of the unplated brass substrate and subsequently substracted for each of the intensity readings obtained from electroplated samples.
X-ray tubes typically have intensities that are several orders of magnitude greater than radioisotope sources. The stated mass per unit area of each coating thickness SRM is certi?
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. Standards representing various thickness ranges of a number of coatings on different substrates are generally available from thickness gage manufacturers. This method sometimes is bb568 as numerical?
Current edition approved June 1, So, the majority of analyzer certifications that Eastern Applied Research technicians provide are for coating thickness applications and those certifications actually reference the ASTM Standard B Material testing you can trust since In general, the radiation intensity varies directly with the current and the square of the potential.
Therefore, consideration should be given to restricting the radiation to the area of interest by masking or collimation at the radiation source.
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. Advanced Plastic and Material Testing, Inc. In those cases where the measurement of thickness on curved surfaces cannot be avoided, a collimator should be used on the excitation beam, reducing the measurement area to a size that will minimize the effects of curvature.
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.
ASTM B (measurement of coating thickness by XRF) | Eastern Applied Research, Inc.
Due to the low intensity of radioisotopes, they are unsuitable for measurements on small areas less than 0. If pores or voids are present, X-ray methods will give an asrm of coating mass per unit area but not of thickness. The intensity of the characteristic silver emission is not in? If the standards are visibly scratched or abraded they should be replaced.
Ideally, the exciting radiation is slightly more energetic shorter in wavelength than the desired characteristic X rays.
ASTM B568 (measurement of coating thickness by XRF)
If not, make sure that the calibration has been made with a substrate having the same thickness and emission properties as the test specimens. Cannot measure elements with an atomic weight less than that of calcium. If the characteristic emission energies of the coating and substrate are sufficiently different, the only contribution of the substrate will be due to background.
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. Our laboratory also provides laboratory services for plastic testingmetal testingrubber testingoil testingpaint testingplating testingadhesive testingcircuit board testingand other testing. Precision and Bias Thus, would give a standard deviation indicating 10 times the precision one-tenth the standard deviation obtained from counts.
This means that during a?
In an energydispersive system, the multichannel analyzer is set to accumulate the pulses comprising the same energy peak. A minimum area of 0. If the coating on the standard is gold, but not electroplated under conditions known to be the same as the coating being measured, the B658 properties ast be assumed to be the same for mass per unit area measurements.
The precision rapidly becomes poorer in the portion of the curve above approximately 10? Users of this standard are sstm advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.
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. 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.