Spark erosive structuring of electrically nonconductive zirconia with an assisting electrode

Nowadays ceramic materials like Al2O3 or ZrO2 are becoming more and more interesting for industrial application and the field of miniaturisation. Due to their outstanding material characteristics like high hardness, bending strength and melting temperature in combination with high brittleness they are hardly structurable via cutting techniques or laser ablation. The electrical discharge machining or spark erosion provides the possibility to structure materials independently of their material properties like hardness or melting temperature. Thus a very large material diversity can be addressed as long as the material offers an electrical conductivity above 0.1 S cm−1. Insulating materials can also be processed via spark erosion when combined with an assisting electrode. In this work a novel lacquer based assisting electrode is introduced that is suitable to start a sustaining erosion process and is applied easily by doctor knife and screen print techniques. Zirconia samples are structured and the process characterised with respect to removal rate, wear rate and wear removal ratio over the erosion depth. Furthermore the influence of two different dielectrics and two electrode materials is analysed, whereby a strong influence of the dielectric and the electrode material is determined. With the gained knowledge precise channel geometries are generated and characterised.