Complementary information from RBS, ERDA and SIMS for analysis of modern magnesium alloys

Technical Mg alloys (AZ91, AM50, AE42 and pure Mg) were used as targets in ion beam sputter deposition of corrosion resistant thin films. Due to the large number of chemical elements and the widespread concentration range between 100 ppm and 90 wt.%, a combination of Rutherford backscattering spectroscopy (RBS), elastic recoil detection analysis (ERDA) and secondary ion mass spectrometry (SIMS) was employed for a quantitative analysis of the resulting film composition. While a lateral and vertical homogeneous layer was observed, the concentration of elements present in precipitates (mainly Al, Si and Mn) in the base material decreased by more than 50% in the deposited film. As the concentration of the other alloying constituents distributed in the Mg matrix remained constant, different angular sputter distributions of the matrix and the precipitates can be inferred from these observations.