Dipentaerythritol: a novel additive for the precipitation of dispersed Ni particles in polyols

Highly dispersed uniform Ni particles ranging in size from 0.1 to 1.2 mu m were synthesized by reducing nickel carbonate in polyols in the presence of dipentaerythritol (DPE) and noble metal salts. DPE was essential in preventing the aggregation of nickel particles, while the noble metal ('seeding' approach) effectively tailored their size. Ferromagnetic particles with a cubic closed packed (ccp) crystal habit were obtained using short reduction times at temperatures below 200 degrees C. Non-magnetic particles with hexagonal closed packed (hcp) structure were obtained after extended heating times (>16 hours) at temperatures above 220 degrees C. The temperature of the reduction and heat-treatment process was adjusted by using polyols with different boiling points.