Effect of Pr2O3 addition on the mechanical properties of the mullite/ZTA composites.

Abstract

To enhance the mechanical and physical properties of Mullite/Zirconia Toughened Alumina (ZTA) composites for advanced engineering applications, rare-earth elements are introduced as dopants. Such composites are characterized by high hardness, fracture toughness, thermal shock resistance, and enhanced physical properties thanks to controlled microstructure through stabilization of the ZrO2 phases, enabling the formation of rod-like particles to enhance mechanical characteristics. In the present study, mullite/ ZTA) doped with 0.5, 0.75, and 1 wt% Pr2O3 and a complete study of their effects on the produced composites were carried out. All batches were dry mixed and shaped using a cold isostatic pressing (CIP) at 300 MPa. The specimens were then pressureless sintered at 1550–1650 °C for two hours, with 50 °C intervals and 5 °C/min firing and cooling rates. Microstructure and phase composition of the sintered ceramic composites were evaluated. Vickers hardness, flexural strength, and fracture toughness tests were used to determine the mechanical properties of the ceramic composites. The densification behavior, microstructure, and mechanical properties of the (mullite/ZTA) composites were found to be significantly impacted by an increase in Pr2O3 concentration.

Keywords: Kaolinite; Mechanical properties; Mullite; Pr2O3; ZTA.