Papers by Keyword: Calcium Zirconate

Abstract: Yttria stabilized zirconia (YSZ) based composite topcoats were prepared with three advanced ceramic materials as second phase component; CaZrO₃, (La_0.75Nd_0.25)₂Zr₂O₇ and Nd₂Ce₂O₇. The solid particles erosion (SPE) testing of the air plasma sprayed composite topcoats was carried out at room temperature and 900 °C to study the effects of second phase on erosion behavior. The erodent was angular fused alumina of 40-45 mm size. The erosion mechanism was followed in all topcoats with cracking and fracturing of the plasma sprayed splats due to erodent particles impact and impingement, whereas micro-ploughing was observed after 900 °C SPE testing as an additional feature. The hardness and intrinsic properties of second phase component in the composite topcoats played a crucial role in improving the erosion rate (ER) at ambient as well as 900 °C. The Nd₂Ce₂O₇/YSZ topcoat show lower ER due to combatively higher hardness of Nd₂Ce₂O₇ and good interfacial bonding with YSZ. The overall lowering of ER at 900 °C as compared to that of at ambient conditions was ascribed to the anelastic mechanical response of the ceramic topcoats due to thermal cycling involved in the SPE testing at high temperature.

Abstract: Alkaline earth titanates and zirconates and their binary systems are of interest for their temperature in sensitive dielectric properties. Calcium titanate and calcium zirconate perovskite ceramics find applications in pulse discharge, energy storage and microwave capacitors. These dielectric materials have been used in electric hybrid and fuel cell vehicles. In the present work, fine crystalline compound powders of calcium titanate and calcium zirconate were prepared by a single step molten salt synthesis. Calcium oxide and titanium dioxide/zirconium oxide were used as precursors to obtain the calcium titanate and calcium zirconate compound powders respectively. The prepared calcium titanate and calcium zirconate compound powders were characterized by TGA, FTIR, XRD, SEM and EDS analysis.

Abstract: The paper describes formation of the phases in magnesia-zirconia refractories due to reaction with the cement furnace charge in a form of pre-calcined meal or Portland clinker containing sulphur and chlorine in a different content at the temperature 1300°C and 1450°C. The studies were carried out by using the coating test. The microstructure changes of the contact zones between coating and the brick were studied by the scanning electron microscopy, SEM, coupled with EDS. The temperature dependence of reactivity the pre-calcined meal and Portland clinker in relation to the magnesia-zirconia bricks has been documented and discussed.