INFLUENCE OF THE ADDITIVE CARBON ON THE COMPACTION OF POWDERS OF PARTIALLY STABILIZED ZIRCONIA DIOXIDE DURING PRESSING AND SINTERING

10.25712/ASTU.1811-1416.2022.04.003

Abstract

Zirconia ceramics has high functional and strength properties. Its fields of application are constantly expanding. The use of nanopowders makes it possible to obtain fine-grained ceramics with improved properties. Zirconium dioxide has a high hardness. This causes increased mold wear. In addition, nanoparticles are prone to agglomeration. This affects compaction during compaction and sintering. These problems can be solved by introducing microadditives. One such additive is carbon. The purpose of this work is to study the influence of the type of carbon addition and its concentration on the parameters of zirconium ceramics from powder raw materials, which is obtained by sol-gel and plasma-chemical methods. The shrinkage of samples of two types of ceramics with three types of carbon addition was studied by dilatometry. They are multiwalled carbon nanotubes (MWNTs), amorphous carbon, and also amorphous carbon with the presence of MWCNTs. We have determined that the introduction of additives does not affect the shrinkage rate, and the highest shrinkage rate of the sample is almost equal to the shrinkage rate during ceramic sintering without additives. We have determined the effect of carbon addition on the density and microhardness of ceramics. The introduction of additives into ceramics from powders obtained by sol-gel technology causes a decrease in density and microhardness. The density of ceramics from plasma-chemical powders increases to a certain threshold value of the concentration of additives. This is true for all types of carbon considered in this study.