Electro discharge machinable alumina-based nanocomposites

Abstract

This work presents the results of an electro-discharge machined ceramic composites consisting of a base non-conductive ceramic component such Al2O3, to which is added sufficient amounts of an electro-conductive ceramic nanoparticles such as TiC, TiNC, NbNC, TaNC, and SiC (whiskers) to achieve an electrical resistance of less than about 100 Ohm.cm. The compositions studied were prepared with the same proportion of raw materials: alumina 42 (vol %) + conductive material (TiC, TiNC, NbNC, and TaNC) 22 (vol %) + SiCw 36 (vol %). SiC whiskers were used to optimize mechanical properties. Fracture toughness is improved up to three times that the corresponding to the individual ceramic components. Strength and hardness is also improved. Cutting tools with 2, 54 x 2, 54 cm2 dimensions and other complex ceramic pieces were machined by using EDM machine, from Pulse Electrical (PECS) sintered compacts. These cutting tools were tested to machine high Cr-base superalloy industrial laminating cylinders without any further dressing, showing different performance that are discussed in this paper.