The effect of yttrium nitrate addition on the densification behaviour of Y2O3 ceramics during the cold sintering process

Abstract

The densification behaviour and phase development of Y2O3 ceramics were investigated as a function of yttrium nitrate (Y(NO3)3·6H2O) solution addition during the cold sintering process at 200 °C. Second phases such as Y4O(OH)9NO3 and Y(OH)3 were observed after the cold sintering process. The amount of Y4O(OH)9NO3 increased with increasing amount of yttrium nitrate, while the amount of Y(OH)3 decreased. The second phases were transformed to fine sized Y2O3 (∼30 nm) particles smaller than those of the raw powder (<400 μm) by sintering at 600 °C. The fine sized Y2O3 particles were located in the voids between the larger Y2O3 particles, thus increasing the packing density and enhancing the densification of the Y2O3 ceramics after the final sintering process.