Physico-Chemical nanomaterials science

Thermal barrier coatings based on powders of the system Al2O3–TiO2–Nd2O3
Tyshchenko J.S., Lakiza S.N., Red’ko V.P., Dudnik E.V.
Frantsevich Institute for Problems of Materials Sciences NAS of Ukraine Krzizanivskoho str, 3, Kyiv-03142, Ukraine.
E-mail:tyshjana@ukr.net

Thermal barrier systems protect the superalloy components of gas turbine engines increasing their durability and enabling them to operate at temperatures substantially above their nominal capability. The continual increase in gas turbine temperatures requires new thermal barrier coating (TBC) materials with increased microstructural stability and reduced thermal conductivity. Most development in thermal barrier coatings has been focused on zirconia-based ceramic materials. One of the approaches to the creation of TBC is based on the use of nanocrystalline powders of multi-component co-doped zirconia  with rare earth oxides, TiO2, Al2O3. 
The basis of new materials creation is the study of physical and chemical interaction, which is reflected in the phase diagrams of the systems. The effectiveness of Nd2O3 when creating a TBC has drawn attention to the The Al2O3‒TiO2‒Nd2O3 system .
Isothermal section of the Al2O3–TiO2–Nd2O3 phase diagram at 1400 °C is constructed for the first time. It is the part of systematic investigations of Al2O3–TiO2–Ln2O3 (Ln=lanthanides, Y) systems. The 1400°C was taken as the temperature, at which no liquid is expected in the system. Isothermal section consists of seven narrow two-phase and eight three-phase regions. Triangulation of the system is determined by the phase Nd2Ti2O7, which is in equilibrium with compounds Al2TiO5, NdAlO3 and system components TiO2 and Al2O3. Formation of phases Nd4Ti9O24, Nd2Ti3O12 and Nd2TiO5 in binary boundary system TiO2–Nd2O3 causes the appearance of partially quasibinary sections Al2TiO5–Nd4Ti9O24, Al2TiO5–Nd2Ti3O12 and NdAlO3–Nd2TiO5. The obtained results make a significant contribution to the understanding of interactions between the components in the system studied. The system includes binary compounds with low coefficient of thermal expansion, what is needed to create new types of TBC.