THICKNESS DETERMININATION OF ELECTROPLATED Ni-P, Sn-Bi AND Sn-Pb COATINGS BY ATOMIC EMISSION SPECTROMETRY WITH A DIRECT CURRENT GLOW DISCHARGE

Abstract

Glow discharge atomic emission spectrometry allows determining the chemical composition of the coatings and their thickness as well as to conduct the depth analysis. Atomic-emission determination of the coating thickness on a single calibration curve can be performed by using the sputtering rates of coatings with different chemical composition.To realize this method the set of comparative samples with Ni-P coating was made. Samples are certified for the coating thickness by a regulated chemical, metallographic and X-ray fluorescence analysis methods. Using the atomic emission spectrometer with a dc glow discharge under optimal operating parameters, which provides a flat bottom of the crater, the calibration curve for dependence of the Ni-P coating thickness against its cathode etching was obtained. It is shown that the metrological characteristics of the current method for control of Ni-P coating thickness is not worse than the methods regulated by GOST.Samples of Sn-Bi and Sn-Pb coatings were made. The thickness of the coating was determined by the regulated methods of analysis, the optimal operating parameters of the glow discharge, which provides a flat bottom of the crater, were determined, and the absolute and relative sputtering rates of coatings in dc glow discharge were measured. Using the atomic emission calibration curve for Ni-P coating and established relative rates of sputtering, the thickness of Sn-Bi and Sn-Pb coatings was determined. It is shown that the metrological characteristics of this method are not worse than the methods regulated by GOST.Methodology for measuring the thickness of Ni-P, Sn-Bi and Sn-Pb coatings using atomic emission spectrometry with a dc glow discharge was developed and certified.Key words: atomic emission spectrometry, DC glow discharge, electroplating Ni-P, Sn-Bi and Sn-Pb, sputtering rate, operating parameters of the discharge, thickness of the coating.(Russian)DOI:http://dx.doi.org/10.15826/analitika.2015.19.1.007 A.L. Chicherskaia, A.A. PupyshevUral Federal University named after the first President of Russia B. N. Yeltsin, Yekaterinburg, Russian Federatio