Comparative evaluation of densification and grain size of ZnO powder compacts during microwave and pressureless spark plasma sintering

In this paper, ZnO powder was consolidated by microwave and pressureless spark plasma sintering (PL-SPS) processes. Comparative experiments are undertaken maintaining conditions of green density, temperature profile and applied pressure. Densification and microstructural characteristics are determined under similar sintering parameters, where the final relative densities of ZnO compacts were improved with increasing sintering temperature for both processing methods. Detailed microstructure investigation indicated that finer grain sizes with higher densification degree can be achieved by microwave sintering as compared with PL-SPS.