Study On Microstructure And Properties Of Plasma Sprayed Yttria Partially Stabilized Zirconia-Cenosphere Composite Coating

Thermal barrier coating (TBC) has the advantages of resistance to high temperature corrosion, abrasion resistance, low thermal conductivity and other characteristics, and it is widely used in aviation turbine engine, combustion chamber and rocket nozzles and other hot end components. However, with the rapid development of modern aviation industry, the working conditions of hot end components is becoming severer, and put forward higher requirements on the performance of the components. The traditional coating has been difficult to meet the new requirements of the project.Cenosphere is very light and the cavity is nearly vacuum, so it has good resistence to heat conduction. Conventional yttria partially stabilized zirconia (YSZ, ZrO2-8wt.%Y2O3) coating and zirconia co-doped with yttria and cenosphere (with volume fraction of10%,20%,30%) coating have been deposited by air plasma spraying (APS). SEM and energy spectrum analysis were used to characterize the microstructure of the coating. By means of X-ray diffraction, the phase structure of the coating was analyzed. The density of the coatings were measured by Archimedes method of drainage; the wear resistance of the coatings were tested; the bonding strength between the coatings was determined by method of drawing; thermal shock resistance experiment were done to detect the service life of the coating; corrosion polarization curves of the coatings were measured to understand the corrosion resistance of the coatings.It is noticed that adding20%volume fraction of cenosphere in the YSZ poweders can reduce the density of the coating by13.2%, compared with the conventional coating.With appropriate spraying power (30kW), spraying distance (100mm) and other process parameters, the microstructure of the coating is uniform and dense. The bonding strength of the coating is37MPa(thickness of100pμm). The coating has good corrosion resistance, wear resistance and thermal shock resistance.This result will have an important guiding significance for the application of the material with lightweight and low thermal conductivity to high temperature protective coatings.