Development of ceramic micro-tools for precision machining

摘要

Ceramic tools on the base of alumina are considered as candidate materials for precision cutting of iron alloys. For this purpose the conventional ceramic cutting tools have to be further developed in order to meet the requirements of a considerably reduced wear rate in particular the absence of any intergranular fracture processes. To achieve this progress, pure alumina powder was classified by centrifugation to average particle sizes of 100 nm in low volume samples to enable the fabrication of a homogeneous, fine-grained microstructure without any noticeable processing flaws. The green compacts were produced by colloidal processing. Sintering led to dense small sized inserts with sub-μm grain sizes and high hardness of 2300 HV_(0.1). The surfaces were finished with a roughness of 1 nm; the tool tip radii have further to be reduced to a level below 100 nm without damaging the cutting edges artificially.