Reference material for the spectral analysis of the VSDP‑16 aluminum alloy

Abstract

The control of the chemical composition of aluminum-based cathodes of the VSDP brand requires a lot of production time, as well as the availability of expensive equipment, which is not suitable for the control of the alloy composition during its smelting. The purpose of this study is to develop a technology for reference material (RM) production for spectral analysis of the VSDP-16 aluminum alloy, which meets the requirements for stability and chemical homogeneity. The RM certified values should cover the alloying range of the alloy for constructing correct calibrations in the calibration of spectrometers.The RM production technology included: melting of ingots of charge bars from the VSDP-16 alloy in a vacuum induction furnace; atomization of bars to aluminum powder; hot pressing of the resulting powder in a graphite mold on a hot pressing unit at a sintering temperature of 600C and a pressure of 20 MPa (62 kN); mechanical processing of the obtained bars. In the course of the study, the processing methods of RM melting were tested by introducing the main alloying elements and impurities. The RM homogeneity study was carried out, and it was found that the homogeneity characteristic of Sн for alloying elements is less than 1 % of the certified value, which suggests a good distribution of elements in the bulk. The study of the RM chemical composition showed that the content of elements varies and allows the RM application for calibration of spectral equipment. Calibration dependences are constructed based on optical-emission and X-ray fluorescence analyzers. Dependences are linear, which makes it possible to apply RM for calibration of spectral equipment. The developed RM is appropriate for the optical-emission method of analysis, which does not include the dissolution of samples in acids. This allows to reduce labor intensity compared to the inductively coupled plasma atomic emission method by ~3 times and energy consumption by ~3.5 times.As a result of the study, a set of certified reference materials was developed for the spectral analysis of the VSDP-16 aluminum alloy GSO 11696–2021, the certified values of which are traceable to the unit of mass fraction by direct measurements on the State Primary Standard of units of mass (molar) fraction and mass (molar) concentration of components in liquid and solid substances and materials based on spectral methods GET 196-2015.