Wear behaviour of mould inserts used in micro powder injection moulding of ceramics and metals

Large-scale production of ceramic and metallic micro components via micro powder injection moulding (μPIM) of filled feedstocks with abrasive particles requires mould inserts with a high wear resistance. Therefore, the wear behaviour of unalloyed, low- and high-alloyed steels, electroplated nickel and brass CuZn37 was studied using a specially developed laboratory tribometer simulating powder injection moulding with zirconia, alumina and steel feedstocks. Highest wear resistance was measured for the high-alloyed steel X175VCrMo9-5 which was produced by a powder metallurgy process. This steel was characterized by a homogeneous microstructure with a martensitic matrix and about 20 vol% fine carbides. In tests with ceramic feedstock the wear resistance of single-phase electroplated nickel was significantly higher than that of the heat-treated tool steels 30CrMo6 and X38CrMoV5-1 of higher hardness. These results indicate that in micro powder injection moulding wear behaviour can depend more on microstructural parameters like homogeneity than on hardness of the materials. The wear behaviour also was strongly influenced by the characteristics of the feedstock (e.g. amount, size, shape and hardness of ceramic or metallic particles).