Fabrication and properties of in situ intergranular CaZrO3 modified microporous magnesia aggregates. Issue 10 (July 2020)

• Record Type: Journal Article
• Authors: Zou, Yongshun; Gu, Huazhi; Huang, Ao; Fu, Lvping; Li, Guangqiang
• Is Part Of: Ceramics international. Volume 46:Issue 10(2020)Part B
• Page Start: 16956
• Page End: 16965
• Publication Date: 2020-07
• Subjects: Microporous magnesia aggregates -- Lightweight refractories -- CaZrO3 -- Slag resistance -- Closed intragranular pores; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.03.279
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Lightweight microporous magnesia aggregates with closed porosity of 6.2%, apparent porosity of 2.1% and median pore size of 2.36 μm were fabricated by introducing nano-sized ZrO2 combined with magnesite decomposition and sintered at 1780 °C. The sintering properties and microstructure revealed that nano-sized ZrO2 promoted the sintering and formation of closed intragranular pores by increasing abundant crystal defects and producing cation vacancies ( V M g ' ' ) raising the migration rate of grain boundaries, which induced a change in porosity type from large open pores to small closed pores. The nano-sized ZrO2 changed the bonding of magnesia grains from single CaO–SiO2 –MgO phases bonding to composited CaO–SiO2 –MgO phases-CaZrO3 phases bonding, significantly enhancing the slag penetration resistance. The closed porosity played a more important role in reducing the thermal conductivity compared with total porosities. The microporous magnesia aggregates and thermal conductivity of 8.994 W (m K) −1 at 800 °C exhibit potential for application in wear lining refractories.