The Use of Cold Sprayed Alloys for Metallic Stents

1- This study shows the ability to successfully cold-spray 316L stainless steel using nitrogen and helium as a propellant gas. The microstructure was characterized with low porosity and fine grain structure. In addition, after post-processing heat treatment, the microstructure became denser (i.e. lower porosity). The microhardness did not change with 400°C annealing temperature but decreased significantly at 800°C, which can be explained by the recrystallization that occurs during cold-spraying. Both the ductility and strength were improved after annealing at 1100°C, in particular. 2- This study shows the ability to successfully cold-spray composite 316L-CoCr using nitrogen as a propellant gas with Co-Cr volume fractions (i.e. 25%, 33.3%). The deposition efficiency decreased with increasing the amount of Co-Cr. The microstructure is characterized by low porosity level in the first two mixes. At 50% as mixed Co-Cr and 316L, the actual as coated material was 33% Co-Cr, due to difficulties in bonding Co-Cr particles to each other. Thus, the porosity was high at the 50% mixture and cracks were also apparent.