Elastic and Flow Properties of Dense, Pure Oxide Refractories

Mechanical properties, including creep rates, were measured for slip‐cast magnesia, hydrostatically pressed magnesia, thoria, zircon, and mullite. None equaled alumina or zirconia in strength, rigidity, or creep resistance. Although mullite was found to have good properties, magnesia showed the best properties of the oxides tested. Thoria was very weak, zircon was highly plastic above 1000°C. Elastic and flow properties were determined primarily by the crystal structure and atomic bonding of the oxides and secondarily by grain boundary conditions.