A new synthetic route to MgO–MgAl2O4–ZrO2 highly dispersed composite material through formation of Mg5Al2.4Zr1.7O12 metastable phase: synthesis and physical properties

• Published in: 矿物冶金与材料学报：英文版 Vol. 24; no. 3; pp. 332 - 341
• Main Author: Peng Jiang;Guo-xiang Yin;Ming-wei Yan;Jia-lin Sun;Bin Li;Yong Li
• Format: Journal Article
• Language: English
• Published: 2017
• Subjects: composite; formation; materials; mechanisms; metastable; phases; physical; properties; refractory; synthesis
• ISSN: 1674-4799; 1869-103X

Mg5Al2.4Zr1.7O12 metastable phase was successfully synthesized from analytical-grade MgO, α-Al2O3, MgAl2O4, and ZrO2 under an N2 atmosphere. The sintering temperature was varied from 1650 to 1780°C, and the highest amount of Mg5Al2.4Zr1.7O12 appeared in the composite material when the sintering temperature was 1760°C. According to our research of the formation mechanism of Mg5Al2.4Zr1.7O12, the formation and growth of MgAl2O4 dominated when the temperature was not higher than 1650°C. When the temperature was higher than 1650°C, MgO and ZrO2 tended to diffuse into MgAl2O4 and the Mg5Al2.4Zr1.7O12 solid solution was formed. When the temperature reached 1760°C, the formation of Mg5Al2.4Zr1.7O12 was completed. The effect of MgAl2O4 spinel crystals was also studied, and their introduction into the composite material promoted the formation and growth of Mg5Al2.4Zr1.7O12. A highly dispersed MgO-MgAl2O4-ZrO2 composite material was prepared through the decomposition of the Mg5Al2.4Zr1.7O12 metastable phase. The as-prepared composite material showed improved overall physical properties because of the good dispersion of MgO, MgAl2O4, and ZrO2 phases.