基于X射线荧光的铝硅共渗涂层厚度测量研究

Study of the Measurement of the Thickness of Aluminum-Silicon Permeability Layer Based on X-Ray Fluorescence

铝硅共渗涂层常喷涂于发动机高温叶片表面,涂层的防护对于延长发动机叶片的使用寿命至关重要。X射线荧光无损检测技术能快速便捷地监控涂层厚度情况,但是目前这种方法对于多元素双层膜铝硅共渗涂层厚度的检测不准确。为了进一步研究多元素双层膜铝硅共渗涂层厚度与X射线荧光检测值的关系,基于X射线荧光无损检测技术提出了一种方法来减小X射线荧光测量数据的误差,再通过验证钼元素荧光对数值与第1层膜厚度之间的线性关系来确定这种方法的可行性,最后基于X射线荧光吸收与发散的原理,拟合出中间层膜的厚度与钼元素荧光之间的计算模型。得出以下结论:当膜中钼元素质量分数大于基底中该元素质量分数时,随着膜厚度值的增加,仪器接收到的荧光效应先减弱再增强,临界值大约为14.3μm,小于该临界值的铝硅共渗涂层,涂层元素相互渗透对厚度测量的影响不可忽视。

Aluminum-silicon co-infiltration coating is usually sprayed on the surface of aeromotor blades which is at high temperature,so as to provide critical protection to prolong the service life of aeromotor blades.the thickness of the coating can be monitored through X-ray fluorescence non-destructive testing technology in a quick and expedient manner,but it is not accurate enough to detect the thickness of multielement double-layer aluminum-silicon co-permeated coating.Further the study of the relation between the thickness of multielement double-layer aluminum-silicon co-permeation coating and the X-ray fluorescence detection value.One method based on X-ray fluorescence nondestructive testing technology are proposed in this paper to reduce the error of X-ray fluorescence measurement.Moreover,the feasibility of the method will be examined by verifying the linear relation between the fluorescence pair value of Molybdenum and the thickness of the first layer.Lastly,based on the principle of X-ray fluorescence absorption and divergence,we will fit a computational model for the relation between the thickness of the intermediate layer and the fluorescence of molybdenum.We find the coating thickness of the experimental sample has a critical value,so that the relationship between thickness and fluorescence value is not monotonously increasing or decreasing.When the mass fraction of Molybdenum in the film is greater than that in the substrate,the fluorescence effect received by the instrument decreases first and then increases with the increase of the film thickness,with the critical value of about 14.3μm.The influence of interpenetration of elements on thickness measurement of Aluminum-silicon permeability coatings less than the critical value can not be ignored.