Effect of the sintering temperature and atmosphere on the microstructural evolution and shrinkage behavior of CuO ceramics

In this study, the densification behavior and microstructural evolution of CuO were examined when this material was sintered at different temperatures in O₂, air and Ar atmospheres. The CuO samples maintained their phases even after prolonged sintering at 900-1100°C in an oxygen atmosphere. When sintering in air, the densification was faster than it was when sintering in oxygen. However, when the samples were sintered at 1100°C, large pores were observed in the sample due to the phase transformation from CuO to Cu ₂O which accompanies the generation of oxygen gas. The pore channels in the sample became narrower as the sintering time increased, eventually undergoing a Rayleigh breakup and forming discrete isolated pores. On the other hand, CuO sintering in Ar did not contribute to the densification, as all CuO samples underwent a phase transformation to Cu₂O during the heating process.