Investigations on vacuum-evaporated CSZ thin films for thermal barrier applications

Abstract

Ceria-stabilized zirconia (CSZ) thin films have been developed over Ni-based alloy substrate by vacuum evaporation method using an electron beam. X-ray diffraction (XRD) analysis of the film heat treated at different temperatures reveals monoclinic phase stabilization. Transmission measurements of the films annealed at different temperatures, in the wavelength region 300-1,100 nm, indicate that the band gap energy of the films lies between 3.6 and 3.8 eV. Refractive index of the films was found to increase with the increase in the annealing temperature. Micro hardness of the films increases nonlinearly with the increase in annealing temperature, indicating an improvement in the hardness of the films. Thermal conductivity studies of the CSZ-coated substrate show a nonlinear decrease with the increase in annealing temperature. Surface investigations of the CSZ films confirm an increase in grain size and a decrease in surface roughness with the increase in annealing temperature of the films.

Influence of Sol Concentration on the Properties of Spin Coated Zirconia Thin Films

“…The low value of band gap may due to the non stoichiometric nature of the films. Moreover the band gap energy has been found to increase with the increase in concentration, which may be attributed to the increases in carrier density with increase in solute concentration [7]. …”

“…There has been great scientific concentration in Zirconia thin films due to their phase transitions. Pure Zirconia exhibits three polymorphs depending on temperature: monoclinic (m) stable up to1170˚ C, tetragonal (t) stable up to 1170-2370˚ C, and above it have cubic (c) phase until it melt at 2706˚ C [7]. The property of thin films strongly lies on the method of preparation and growth parameters.…”

Microstructures, Thermal Shock Resistance and Isothermal Oxidation Resistance of Nanostructured Ceria Stabilized Zirconia Coatings

“…turbine blades) with better efficiency. Yttria stabilized zirconia (YSZ) was usually selected as the thermal insulating coating material due to its low thermal conductivity, high thermal expansion coefficient and good corrosion resistance [1].In recent years, some investigators have reported that ceria stabilized zirconia (CSZ) coatings have not only high temperature stability, good corrosion resistance and high fracture toughness but also lower thermal conductivity and high thermal expansion coefficient than YSZ coatings [2][3][4]. Therefore, CSZ looks to be more promising as a new candidate material for the TBC application in more severe environment.…”