Combustion characteristics of zirconium particles coated with ferrite nanoparticles

To improve the properties of Zr powder for specific applications in aerospace and military fields, Zr powders were coated with ferrite nanoparticles, namely FeOOH, Fe₂O₃, and Fe₃O₄. An instantaneous flame propagation system and scanning electron microscopy, X-ray diffraction, thermogravimetry, and differential scanning calorimetry techniques was used to characterized the flame propagation characteristics, micromorphology, phase composition, crystal structure, thermal stability, and reactivity of the three types of nano ferrite-coated Zr particles. The results showed that, the flame propagation velocity and maximal temperature exhibited the following order: Fe₂O₃-coated > FeOOH-coated > Fe₃O₄-coated Zr dust cloud. With an increase in the proportion of coating materials, the combustion characteristics all decreased. The contrastive analysis of surface, ingredient and heating process revealed that, during combustion, in addition to inducing oxidation–reduction, inner Zr led to a replacement reaction with the outside ferrite coating layer, and then, Fe generated was oxidized at a high temperature.