Study of ZrB 2 (BMn, V, Cr) intermetallic compounds by laser microprobe mass analysis

Abstract

The effect of the hydrogen activation process on the concentration of intermetallic compound (IMC) alloy components in near-surface layers and in the bulk was investigated by means of laser microprobe mass analysis (LAMMA 1000 prototype). Nine AB 2-type samples were analysed: ZrV 2, ZrV 0.5Cr 1.5, ZrV 0.2Cr 1.8, ZrCr 2, ZrVMn, ZrCrMn, ZrMn 2, Zr 0.8Mn 0.2Mn 2.0 and Zr 0.7Mn 0.3Mn 2.0. For comparison, the samples were measured both in the activated and in the non-activated form. In each case, mass spectra relating to the surface (depth of 0.1 μm or less) and to the bulk (depth of 0.3 μm or more) were recorded. The quantification of the mass spectra intensities was carried out using relative sensitivity coefficients, as related to Zr, i.e. the element common to all the IMCs investigated in this study. The data obtained show that the surface compositions of non-activated and activated materials are quite similar. However, these compositions deviate from the bulk stoichiometry in that Zr is enriched in the near-surface region. It is found that the Zr segregation is oxygen induced in the case of non-activated materials and is hydrogen induced in the case of activated materials, whereby the extension of the Zr enriched layers is thin and thick, respectively.