Structural Effects in Determining Silicon Concentration in Al - Si Alloys by X-Ray Fluorescence and Mass Spectrometry

Abstract

The paper discusses how the structure of aluminum alloys affects the determination of silicon by x-ray fluorescence and glow-discharge mass spectrometry. As the silicon microcrystals enlarge, there tends to be an exaggeration of its content. The kinetics of the silicon-ion concentration change in the glow-discharge plasma show that cathode sputtering causes reconstruction of the surface layer. The processes are different for a binary alloy (with 3% silicon) as against multicomponent alloys. A method is proposed for diminishing the structural effect, which is based on preliminary treatment of the surface with microsecond pulse discharges, which results in a microcrystalline surface layer of thickness 20–50 µm. This suppresses the structural effects and provides reliable data on the silicon content.