Shock Wave Driven Solid State Phase Transformation of Co3O4 to CoO Nanoparticles

The phase transition of Co3O4 into CoO is demonstrated by the impact of shock waves, and the mechanism is studied and reported. The required quantity of Co3O4 nanoparticle (NPs) is synthesized by coprecipitation method. 2.0 MPa transient pressure shock wave is utilized to understand the shock wave induced phase transition in Co3O4 NPs. XRD and Raman studies reveal that the phase transition occurs at 150 shocks in loaded condition. The obtained values of optical band gap energy show that there are changes in band gap energy with respect to the number of shock pulses. SEM images portray that the surface morphology and shape of the particles are considerably changed by the impact of shock waves due to the dynamic recrystallization. Vibrating sample magnetometer (VSM) shows the switchable magnetic phase transition from superpara-para-superpara magnetic behavior. The mechanism of the shock wave induced phase transition is described.