Effect of Deposition Temperature on the Surface, Structural, and Mechanical Properties of HfO2 Using Chemical Vapor Deposition (CVD)

A high-temperature-resistant and high-performance hafnium oxide (HfO2) coating for aerospace engines was developed. HfO2 thin film coatings were prepared by chemical vapor deposition (CVD) at 1200, 1250, 1300, and 1350 degrees C, respectively. The crystal structure and surface morphology of the HfO2 thin films at different deposition temperatures were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The effect of deposition temperature on the mechanical properties of the HfO2 thin films was studied by means of the drainage method and nanoindentation. The results showed that the HfO2 coatings deposited at different deposition temperatures are monoclinic crystal structures, and the surface morphology changes from cellular particles to columnar particles, and finally, to a loose and porous layered structure. When the deposition temperature is 1300 degrees C, the density of the HfO2 film is the highest, 9.62 +/- 0.03 g/cm(3), and the hardness is the highest, 7.33 +/- 0.04 GPa. A HfO2 coating with the best comprehensive mechanical properties was prepared by changing the deposition temperature, which provided an experimental basis for the application of a HfO2 coating in the aerospace field.