Effects of Material Reactivity on the Sintering Properties of Magnesium Oxide Partially Stabilized Zirconia Metering Nozzle

Abstract

In this study, a magnesium oxide partially stabilized zirconia (Mg-PSZ) sample was prepared by granulation, molding, drying, and calcining. MgO was used as stabilizer, along with chemical-and electrofusion-made zirconium dioxide (ZrO2) powder, as well as a different mixture of the two as the raw material. The effects of material reactivity on the sintering properties of the Mg-PSZ metering nozzle were studied by analyzing the physical properties and microscopic structure of the sample. The results show that, under the same sample preparation conditions, the electrofusion-made ZrO2 had lower reactivity, resulting in a lower percentage of stable phase, loose adhesion among particles after sintering, more than 20% porosity, and poor antierosion and antiscouring performance. However, electrofusion-made ZrO2 only had a shrinking percentage of 6%, leading to a higher sintering yield. However, compared with the electrofusion-made ZrO2, chemical-made ZrO2 had a higher reactivity, better sintering properties, more stable phase component, and approximately 75% less porosity. Chemical-made ZrO2, however, had a shrinking percentage as high as 20%, causing serious sample cracking after sintering. Therefore, both types of ZrO2 are not ideal as the only raw material for Mg-PSZ metering nozzles. Nonetheless, when a 1:1 mixture of the two types of ZrO2 was used as the raw material, the calcined sample showed better property parameters in porosity and volume density, as well as compressive strength, satisfying the requirements for Mg–PSZ-based metering nozzles.