The Effect of Bismuth Oxide Additive on Sintering of Zirconia Ceramics at Reduced Compaction Pressure

Abstract

The influence of the low-melting additive bismuth oxide on the consolidation processes of partially stabilized zirconium dioxide nanoparticles in compacts obtained under compacting pressures was studied: 1, 50, and 800 kg/cm². It is shown that, at a compacting pressure of ≤50 kg/cm², the density of the compacts is comparable in magnitude to the bulk density. It has been established that the introduction of a low-melting additive facilitates the production of ceramics from compacts of low density obtained at pressures from 1 to 50 kg/cm². At compacting pressure ≥50 kg/cm², the presence of the additive helps to obtain ceramics with a density of ≥5.8 g/cm³. During sintering, the concentration area of the additive is located in the intergranular boundaries. The presence of additives in ceramics, due to phase transformations with temperature changes, leads to crack formation mainly along grain boundaries. For low compacting pressures, a decrease in porosity and an increase in density and average grain size are observed as the compacting pressure and the content of the low-melting oxide additive increase. The research results are of great importance for the development of new ceramic 3D printing technologies.