Properties Of Sintered Ceramics Research Articles

Zirconia-Based Powders Produced by Plasma-Spray Pyrolisys and Properties of Sintered Ceramics

It have been studied zirconia-based powders and sintered ceramic. It was shown that in the porous structure of zirconia-based ceramics there is a critical value of porosity the material divides into two sub-systems, being variously deformable under external loading. It have been shown that m-phase in ZrO2 is formed due to increase in the microdistortion level which destabilizes the nanocrystalline t phase. It has been found out the correlation between the sizes of crystallites and porosity, which associated with transition of the isolated porous structure to the continuous one and the porosity of 20%, corresponds to the first percolation threshold.

The Effect of SiAlON Precursor Nanostructurization in a Planetary Mill on the Properties of Sintered Ceramics

The results on the effect of nanostructured β-sialon precursor on the sintering and properties of the resultant ceramics are presented. The standard mixture of β-sialon precursor with 0.4z substitution degree was activated for 30 min in a planetary mill with an acceleration of 28g. Activation in the planetary mill resulted in diminution of the crystallite size and significant imperfection of the crystal lattice of the powder particles. The sintering experiments were performed at 1450-1600 °C in a powder bed. The relative density of the sintered bodies achieved the value of 97 %. The nanostructured material was produced after pressureless sintering at 1500 °C. It is concluded that high activation degree of the powders is necessary to obtain fully dense ceramics.