Abstract：The coating weight of chromate conversion film on surface of galvanized steel sheets is an important factor for the control of production technology and chromate conversion film thickness. In order to improve the efficiency of field quality control and reduce the cost of quality control, it is urgent to develop a method with simple sample preparation for the real-time and on-line analysis of coating weight of chromate conversion film. The standard sample was prepared by punching method. A method for the real-time, on-line and quantitative analysis of coating weight of chromate conversion film on the surface of galvanized steel sheets was established by portable X-ray fluorescence spectrometer (PXRF). Since the coating weight of chromate conversion film had certain relationship with the content of Cr, it was characterized by the analysis of Cr element. In order to obtain the optimal excitation effect of Cr in chromate conversion film system on the surface of galvanized steel sheets, five different analysis conditions were compared. The selected analytical conditions in experiments were listed as follows: the voltage was 15kV, and the current was 10μA. The interference overlapping correction among spectral lines of elements was investigated. Meanwhile, the interference of matrix element with the determination of testing elements was discussed. The matrix effect was corrected by α empirical coefficient method to avoid the influence of matrix elements (Zn and Fe) on the analysis accuracy of Cr. The calculation method of detection limit was explored. The samples with low coating weight were used as testing samples, and the detection limit was calculated based on the standard deviation of multiple determination results. It was found that the detection limit of coating weight of chromate conversion film was 0.92mg/m2. The precision test of method was conducted. The relative standard deviation (RSD) was controlled within 1.5%. The proposed method was compared with inductively coupled plasma atomic emission spectrometry (ICP-AES), and the relative error was less than 2.5%. The accuracy of method could meet the requirements of field quality control. The real-time and on-line analysis of samples was realized, and the test efficiency was improved.
王小欢. 便携式X射线荧光光谱仪分析镀锌板铬盐钝化膜涂镀量[J]. 冶金分析, 2018, 38(8): 11-15.
WANG Xiao-huan. Determination of coating weight of chromate conversion film on surface of galvanized steel sheets by portable X-ray fluorescence spectrometer. , 2018, 38(8): 11-15.
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