Effect of ball milling time on Fe₂O₃/Al nano-composite powder

The Fe₂O₃/Al nano-composite powder was prepared by high energy ball milling method. The effects of milling time on microstructure, morphology and thermal properties of the powder were systematically investigated by means of XRD, SEM and TGA/DSC. The results show that with the increase of the milling time, aggregated Fe₂O₃ microparticles are embedded in Al particles gradually. The microparticles are well dispersed and uniformly distributed, and crystal size of Al powder is decreased continuously. When the milling time is up to 20 h, Al powder can be evenly distributed on the micron Fe₂O₃ particle surface, and dynamic balance state forms between grain growth and grain size decrease, meanwhile thermal reaction enthalpy is the highest. When the milling time exceeds 20 h, the thermal reaction enthalpy of nano-composite powder reduces, and the powder is easy to aggregate.