This paper examines the potential of thermal spray coatings for manufacturing and repairing twin-screw rotors. The coatings evaluated were produced by atmospheric plasma spraying (APS). Tests show that 7% yttria stabilized zirconia (ZrO 2 7Y 2 O 3 ) coatings provide sufficient run-in characteristics and corrosion resistance. The coatings, along with a NiCrAl bond coat, were applied to various substrate materials.

Coatings with magnetic properties were produced by vaccum plasma spraying of different Nd-Fe-B powders onto stainless¬steel substrates. Microscopic examination of the coatings in a light microscope revealed a low porosity and a good bonding to the substrate. Scanning electron microscope examinations have shown different phases in these coatings. The magnetic properties of the coatings are also presented. Paper text in German.

This paper examines thermal insulation layer systems with regard to their thermal shock resistance, internal stresses, adhesive tensile strength and layer morphology. The research was conducted on a duplex coatings system consisting of zirconium dioxide/yttrium oxide ceramic coatings and CoNiCrAlY oxidizing and corrosion resisting coating. In all thermal insulation layer systems, the bonding layers were produced by vacuum plasma spraying. The thermal insulation layers were produced on the one hand by atmospheric plasma spraying and on the other hand by vacuum plasma spraying, and their properties were compared with one another. Paper includes a German-language abstract.