Influence of type, dispersion and amount of alumina on the properties of pressed refractories based on fused zirconia stabilized with ~10 % yttrium oxide

Abstract

The influence of three types of α­alumina, which differ in dispersion — the specific surface area of particles of 1, 3, and 5 m2/g (two of them are active alumina) and their amount (up to 4 %) on the main properties of samples from fused ZrO2 stabilized with ~10 % Y2O3, fired at 1580 °C was studied. The optimum additive, as well as its amount (1 % alumina of lower dispersion), which ensures the production of fired samples with high property indicators, were determined: content of ZrO2 + HfO2 87.80 wt. %, Y2O3 9.20 wt. %, Fe2O3 0.15 wt. %, apparent density 4.71 g/cm3, open porosity 21.0 %, cold crushing strength 31 N/mm2, thermal shock resistance 13 heat cycle (1300 °C — water). No significant advantage of the Al2O3 additive in the form of active alumina has been established, so less dispersed alumina is preferred for economic reasons.
 As a result of the research performed at JSC “URIR named after A. S. Berezhnoy” institution, the technology of products made of fused ZrO2 stabilized with ~10 % Y2O3 was improved, which ensures the production of these products with a higher (although slightly) cold crushing strength and ~3 times higher thermal shock resistance (1300 — water) compared to similar characteristics of currently manufactured products. This can ensure a longer service life of refractories made of fused ZrO2 stabilized with ~10 % Y2O3 and with Al2O3 additive (due to their much higher thermal shock resistance compared to refractories of the same composition but without Al2O3 additive) in various thermal units at consumers’ facilities where this characteristic of refractories is most important.
 Based on the study results, regulatory documentation was developed and full­scale samples of industrial­format products were manufactured.