Impact of Stabilizing Ligands on Densification of Iron Nanoparticles by Pressureless Sintering

This work reports on the densification of iron nanoparticles by slow drying followed by pressureless sintering. In contrast, most previous work has used high heating rates to both dry and density the nanoparticle suspension in a single step. Laser heating has been required to achieve high densities by this approach. The slow drying/pressureless sintering approach is shown to be sensitive to reactions between the particles, the stabilizing ligands, the atmosphere, and the substrate. The sintering rate of iron nanoparticles and the final composition of the deposits are significantly impacted by these interactions. However, in both the cases studied, the nanoparticles densify under pressureless sintering. When the iron nanoparticle colloid is dried in a porous steel skeleton, it is shown to increase high-temperature strength and reduce the sintering shrinkage