1992 Volume 78 Issue 1 Pages 186-193
Homogeneous single phase di-chromium nitrides, ε-Cr2N1-x, with nitrogen concentrations from 9.8 to 11.4 mass% were produced by nitriding pure chromium under different nitrogen gas pressures at temperatures between 1373 K and 1 523 K. A correlation between the nitrogen concentrations and NKα intensities was represented as a straight line. This can be used as a calibration curve. A coated multi-layer X-ray dispersion element, specifically designed for NKα, was used as an analyzing crystal. A nitrogen concentration of ε phase which appeared as a second phase in a Cr-40Ni-5N alloy equilibrated at 1 523 K, was determined by utilizing the calibration curve.
A ZAF correction method developed for light elements by RUSTE and GANTOIS was confirmed to be better suited for nitrogen. Nitrogen concentrations of π phase: a nitride with the metal-atom arrangement of β manganese, which appeared as one of two or three phases in both Cr-40Ni-5N and Cr-35Ni-5Fe-5N alloys equilibrated at 1273 K, were determined by selecting Cr2N0.91 as a standard specimen for nitrogen and applying the ZAF correction by RUSTE and GANTOIS. The nitrogen concentrations of the π phase determined by EPMA were confirmed by average nitrogen concentrations in the specimens determined by an inert gas fusion method.