Examination of mechanical properties of MgO ? spinel composite refractories with the addition of zircon ? Y2O3

The variations and improvements with the reasons on the mechanical properties of the materials containing different compositions that can be obtained with the addition of various amount of zircon and yttria into MgO?Spinel composite refractories were examined and thermal parameters affecting high temperature behaviour of those materials were investigated. The density, strength, Young?s modulus, fracture toughness, fracture surface energy, work of fracture, critical crack length and mean MgO grain size values of the samples produced were measured and evaluated. In addition, microstructural changes using XRD mesurements and SEM analysis were examined. Thermal stress/shock parameters (R, R???, R????, Rst) and ?wof/?S ratios that are used for determining high temperature performance of refractory materials were calculated. The relationships between mechanical properties and structural variations for different compositions and the factors affecting this connection were investigated. The optimum amount of constituents incorporated into composite refractory materials has been determined. The optimisation of materials used for obtaining longer service life in industried application has been carried out.