W-Re alloys, used in rotating anodes for the generation of X-rays, experience severe thermomechanical cycling during their employment. The resulting surface erosion is characterized by cracks, localized melting, and a general roughening. Combined with the inherent brittleness of the material, the preparation of expressive polished cross-sectional cuts is rendered challenging. To maximize the image quality in electron backscatter diffraction and scanning electron microscopy, various preparation methods were compared. A special focus was placed on the rounding of the anode’s top layer as well as on break-outs. The examined methods included mechanical grinding and polishing (MG, MP), flat milling (FM), chemical-mechanical polishing (CMP) and electrochemical polishing (ECP). Investigated were both, non-coated samples as well as samples coated with Mo. Several of the Mo-coated samples were prepared with an additional W-sheet covering the anode’s surface to increase the edge stability.

While MP and FM did not yield a satisfactory image quality, ECP for 10 s at 26 V using a 2% aqueous NaOH solution resulted in a superb outcome. Drawbacks of using ECP were amplified material removal at the sample edges, pores, and crack flanks. Furthermore, etch pits at <111>-oriented grains appeared.

In summary, CMP of a Mo-coated sample with an additional W-sheet for 20 min resulted in low levels of break-outs and edge rounding, combined with a good image quality towards the evaluated sample edge. Therefore, this method was identified as the most suitable approach.