METHOD FOR MEASURING THICKNESS OF PAINTED FILM BY FLUORESCENT X RAY

摘要

PURPOSE:To measure the thickness of the painted film without destruction accurately in a short time by measuring the intensity of the fluorescent X rays with respect to a metal plate on which the paint including a specified element is painted, and computing the thickness of the painted film from the value which has been measured in advance. CONSTITUTION:The paint including the specified element is painted on the metal plate to the thickness which exceeds the limit against the fluorescent X rays excited from the specified element included in the paint. The X rays are irradiated to the metal plate from the painted film side. The intensity of the fluorescent X rays excited from the element in the painted film and the intensity of the fluorescent rays which are excited from a ground metal and absorbed and attenuated by the specified element in the painted film are simultaneously measured. The rate of inclusion of the specified element in the painted film is computed from the relationship among the measured value, the intensity of the fluorescent X rays and the rate of inclusion of the element which have been measured in advance. The painted film thickness is computed from the relationship between the previously measured intensity of the fluorescent X rays which are excited from the ground metal and absorbed and attenuated in response to the rate of inclusion of the specified element in the painted film.