Effect of dwell time on cold sintering assisted sintering based highly transparent 0.9K0.5Na0.5NbO3-0.1LiBiO3 ceramics

0.9K(0.5)Na(0.5)NbO(3)-0.1LiBiO(3) (KNN-0.1LB) transparent ceramics with high optical transmittance of 74% (at 900 nm) were successfully prepared by cold sintering assisted sintering (CSAS) method. The effects of CSAS process and dwell time on transmittance, phase structure, microstructure and electrical properties of the ceramics were investigated in detail. Comparing with conventional sintering (CS), the CSAS process can significantly increase the densities of KNN-0.1LB ceramics. The potassium-rich phase induced by dissolution-precipitation during CSAS process adheres to the grain boundaries and the grain surface, inhibiting the volatilization of potassium/sodium and grain growth. Under the condition of long dwell time, the potassium-rich phase and alkali metal elements introduced by the liquid medium of CSAS process can effectively compensate for the volatilization of A-site ions. Simultaneously, proper dwell time also helps to eliminate pores and promote densification. As a result, the properties of CSAS-based KNN-0.1LB ceramics have been evidently improved, which indicating the CSAS process can guide the design and fabrication of other transparent ceramics with excellent performance. (C) 2020 Elsevier B.V. All rights reserved.