Certified reference materials for microanalysis of carbon and nitrogen

摘要

In many materials, particularly steels and wear resistant coatings, carbon and nitrogen play a major role in determining performance, but are difficult to analyse by electron probe microanalysis (EPMA). Because of the importance of the measurement method, many different organisations have evolved their own 'standards' and reference materials, but none of these is generally accepted or certified by internationally recognised bodies. Increasing tightness of specifications requires highly accurate analysis and, without validation of the existing methods, there can be no certainty as to the results obtained in individual organisations. While reference materials for carbon and nitrogen exist for macroscale analysis, none has been certified and validated for carbon or nitrogen at the microscale (1-3 mu m~3). Here, the particular problem is to produce and certify material that is homogeneous at the microscale. The work of Bastin and Heijligers~(1,2) on quantitative analysis of carbon and nitrogen provided much valuable information for the work in terms of defining procedures for microanalysis used in the validation stage of the work. When a satisfactory production route had been established, 200 specimens were delivered to the Institute Reference Materials Measurement (IRMM).