Exceptional micromachining performance of silicon carbide ceramics by adding graphene nanoplatelets

Abstract

The electrical discharge machining (EDM) performance of silicon carbide (SiC) ceramics containing graphene nanoplatelets (GNPs) is investigated for the first time. Under fine machining conditions, the material removal rate (MRR) dramatically increases up to 186% when 20vol.% of GNPs are added to SiC ceramics, leading to reductions on the electrode wear rate of 132%. The EDMed nanocomposites exhibit surface roughness ≤0.8μm. This outstanding EDM response of the graphene nanocomposites as compared to monolithic SiC is explained by their enhanced transport properties, establishing a direct dependence of MRR with the electrical conductivity. EDM performance of the nanocomposites also depends on the testing direction for materials with low GNPs connectivity (≤10vol.%). Melting/evaporation are the main removal mechanisms, thermal spalling also operating for low thermal conducting materials. The employ of EDM on SiC/graphene nanocomposites allows machining microparts with a fine dimensional precision, opening new opportunities for SiC-based microcomponents.