DEVELOPMENTS AND APPLICATIONS OF QUANTITATIVE SURFACE ANALYSIS BY ION MICROSCOPY (ALUMINUM, ZINC).

摘要

Secondary ion mass spectrometry (SIMS) is used to study the surface and in-depth composition of solid materials. The methodology of SIMS and some important analytical parameters are studied. Instrumental developments concerning automation of data acquisition and processing are performed. A microcomputer using CAMAC as an interface is implemented on the CAMECA IMS-300 ion analyzer. The development of hardware and software results in a versatile and user-friendly system.; The different methods described in literature for quantisation of SIMS need support from the use of well-certified standard materials in the calibration procedure. Secondary ion micro-analysis is thus used to investigate the homogeneity (at the microlevel) of a number of standard reference materials. The sampling constant concept is applied in order to evaluate the applicability of reference materials for microprobe analysis. The degree of heterogeneity is estimated and the number of replicate analyses required for achieving a desired precision is calculated.; The Matrix Ion Species Ratio (MISR) method is used for the quantitative SIMS analysis at trace element levels in metallic matrices. A comparison is made between the results of the MISR method for quantification of SIMS data and spark source mass spectrometric analysis. For the matrix constituents at high concentration levels and for alloy systems, quantitative SIMS is hampered by large variations in the secondary ion yield as a function of the matrix composition. These matrix effects are studied for a Al-Zn binary alloy system, which is used as a coating on steel wire. Relative ionisation coefficients of Al and Zn sputtered from the alloys, are measured as a function of the solute element concentration.; The method then is applied to the determination of the aluminum and zinc concentrations in different phases of a 55 w. % Al-Zn alloy coating on steel wire. The surface and in-depth composition of the overlayer are studied. Also, SIMS analyses are performed of Al-Zn coated wire samples, which were exposed for a 3.5 year period to a rural and marine environment. In this way the identification of corrosion products and the assessment of the influence of the atmospheric environment is performed.; SIMS is then used to the study of an environmental problem: the quantitative analysis of electric steel furnace dust particles and the determination of the enrichment of various elements at the surface of these dust particles.