Origin and evolution of paramagnetic states in mixtures of ZnO and carbon nanoparticles during intensive mechanical treatment

In this study, the microstructural evolution and reaction processes in the mixture of ZnO + xC nanoparticles during prolonged high-energy mechanical activation were explored. The formation of paramagnetic centers has been identified. It was observed that the evolution of various paramagnetic defects reveals several macroscopic flow processes that take place in the system. Some of these processes are the destruction of primary durable nanoparticle ZnO aggregates, the crushing of individual nanoparticles (250–14 nm), the development of accumulative thermal processes in the sample, the interaction of carbon atoms with oxygen from the treatment chamber and from the surface of the ZnO nanoparticles, the formation of reducing atmosphere in the grinding chamber, and the occurrence of the forming conditions of the phase transition ZnOW → ZnOS on the surface layers of ZnOW nanoparticles.