This study first prepared B-doped SiO 2 coating by hybrid sol–gel method. SiO 2 coatings had been successfully used for thermal protection, but its toughness, oxidation resistance and cost are weak points. Hybrid sol–gel method could prepare ultra thin and low cost SiO 2 coatings on nickel alloys. And doping B could improve the coatings’ toughness and oxidation resistance. Thermogravimetry, differential thermal analysis and Fourier transform infrared spectroscopy were used to investigate the additives’ effect on coatings’ formations at different temperatures. X-ray photoelectron spectroscopy and X-ray diffraction were used to investigate the coatings’ element distribution and phase. The results showed that B-doped SiO 2 thermal protective coatings could withstand 1050 °C, and Si–O–B bond was generated to improve the coatings’ toughness. A crystal mullite phase formed on the coatings’ surface at high temperature by thermal diffusion of Al, which significantly improved B-doped SiO 2 thermal protective coatings’ oxidation resistance.