An investigation of ion beam and pulsed laser Ni-SiC mixed surface structures by cross-sectional TEM

Abstract

Ion beam and pulsed laser mixing have been used as surface modification techniques in an attempt to increase the mechanical properties of sintered α-SiC. Thin Ni overlayers (50 nm - 100 nm) were evaporated onto the SiC surface and subsequently irradiated with pulses of a krypton-fluoride (KrF) excimer laser or bombarded with high energy Si+ ions. Both techniques are non-equilibrium processing methods capable of inducing unique microstructural changes at the specimen surface which, under particular processing conditions, can result in enhanced physical properties. It has been shown previously that laser annealing of Ni-coated α-SiC resulted in a fracture strength increase of ≈20%; however, the fracture strength was not changed following ion beam mixing. High resolution cross-sectional transmission electron microscopy (X-TEM) was used to characterize the extent of mixing between the Ni and the SiC following surface modification.