METHOD AND APPARATUS FOR X-RAY FLUORESCENCE GAUGING OF A HIGHER ATOMIC NUMBER SELECTED ELEMENT IN A COATING ON A BASE.

摘要

1,239,797. X-ray fluorescence gauges. MINNESOTA MINING & MFG., CO. Aug.27, 1968 No.40962/68. Heading G1A. The mass per unit areas of an element in a coating the element having an atomic number one or only a few higher than any other excited element in the base or coating, is determined by a non-dispersive X-ray fluorescence gauge using a filter having an absorption edge at a wavelength slightly shorter than an emission wavelength of the coating element, and comparing the output of the gauge with the output corresponding to a reference coating. Examples of coating materials are Zn, Ni and Fe and for a coating of Zn on Cu, a Zn filter is used. The criteria for selecting the filter thickness are discussed. In the measurement of the thickness of a silver coating also containing titanium dioxide, zinc oxide is added to the coating compound and the X-ray generator excitation potential is enough to excite Zn and Ti, but not Ag.