Atom probe analysis of carbonitride grains in (Ti,W,Ta,Mo)(C,N)(Co/Ni) cermets with different carbon content

A series of three alloys with varying carbon content has been characterised using atom probe microanalysis, transmission electron microscopy and energy dispersive X-ray analysis. The atom probe was mainly used to determine the composition of the rim of carbonitride grains. It was found that the amount of tantalum decreases with increasing total carbon content, whereas neither the tungsten content nor the N/(C + N) ratio in the rim seem to be particularly affected by the overall carbon content. The results can be understood from how the content of tungsten in the cobalt/nickel binder phase is controlled by the total carbon content in the material and from the composition and volume fraction of the different phases in these complex materials.