Nanostructured ceramic materials synthesized from ZrO2 that can withstand thermal shock when immersed in molten steels

Abstract

This paper presents a review on the synthesis of nanostructured ceramic materials that can withstand thermal shock when immersed in molten steels and work as solid electrolytes. The authors examine the possibility to obtain heat-resistant dense cera mics from ZrO2 – MgO and ZrO2 – Y2O3 powder systems with a controlled particle structure for the manufacture of solid electrolytes of steel oxidation sensors to be used in contact with corresponding molten steels. The paper describes a method for producing nanostructured ceramics of the ZrO2 – MgO system with enhanced heat resistance from nanocrystalline powders, as well as the properties of sensitive elements. Thus, the paper looks at obtaining zirconium dioxide ceramics that would have a heat-resistant structure due to which it can be used in molten steels. It is shown that due to nanocrystalline inclusions in the ceramic structure the material becomes heat-resistant and conductive when immersed in molten steels at the temperatures of 1,550 to 1,800 oC. The paper also describes the results of a study that looked at the process parameters for the production of sensitive elements with an optimal heatresistant structure. Also presented are the results of field tests conducted for sensitive elements with solid electrolytes of various compositions A ZrO2 + 2.0 wt. % MgO sensitive element made of precipitation synthesized powders proved to have the best performance: i.e. stabilization time; EMF after immersion; variation within the area of stable readings in highly deoxidized steels. The structure of such powder contains a large amount of ellipsoid tetragonal phase precipitates. The researches were conducted using the equipment of the Research sharing center named after D. I. Mendeleev within the framework of the project No. 075-15-2021-688.