The concentration of Benzotriazole plays an important role in the mechanical properties of ceramic coatings. In this work, hybrid nano-composite zirconia–alumina–Benzotriazole coatings with 1.2, 2.4, 3.6 and 4.8% of Benzotriazole are deposited on the Al 2024 substrate by the sol–gel technique. The phase, structure, and morphology are determined by grazing-incidence X-ray diffraction, Fourier-transform infrared spectroscopy, and field-emission scanning electron microscopy and the nano-mechanical properties are assessed by atomic force microscopy at loads of 50 and 60 µN. Uniform and homogenous amorphous coatings are deposited at 150 °C and the thicknesses of the zirconia–alumina and zirconia–alumina–Benzotriazole coatings with 1.2%, 2.4%, 3.6%, and 4.8% Benzotriazole are 670, 560, 750, 790, and 1040 nm, respectively. The surface roughness of the coatings decreases by 3.5 and 8 times after introducing 1.2% and 3.6% Benzotriazole to the coatings, respectively, but further increasing the Benzotriazole concentration from 3.6 to 4.8% decreases the hardness, strength, and maximum shear tension. The optimal concentration of Benzotriazole depends on the Hertzian pressure and the hardness and strength of the zirconia–alumina–3.6% Benzotriazole under a load of 60 µN are 23 and 46 times higher than those of the zirconia–alumina coating. The smallest friction coefficient of 0.11 is observed at a load of 60 µN and abrasive wear and shear are dominant.
