Preparation of ZrO 2 –Al 2 O 3 Composite Gel Film by Sol-Gel

In this paper, ZrO2–Al2O3 composite sol prepared by zirconium oxynitrate and isopropanol aluminum precursor was fabricated by sol-gel method. ZrO2–Al2O3 composite gel film was prepared on the surface of zirconium hydride in turns by dip-coating and heat treatment. The morphology and phase structure of the composite gel film were analyzed by scanning electron microscopy (SEM), confocal laser scanning microscope (CLSM) and X-ray diffraction (XRD). Differential scanning calorimetry and thermogravimetry (DSC-TG) analysis were performed to investigate the behavior of composite sol in the heat treatment. The results show that ZrO2–Al2O3 composite gel film with about 20 μm in thickness is uniform, continuous and compact on the surface of zirconium hydride. There is substantial weight loss in the TG curve before 500 ℃. After that, TG curve is flat. The total weight loss of ZrO2–Al2O3 composite sol is 74.2% in the heat treatment. Composite gel has amorphous structure at 600 ℃, and it is mainly composed of T-ZrO2 between 700 and 800 ℃. The aim of crystal stabilizer alumina is to inhibit phase transformation of zirconia.