Abstract: The SiO₂ layer was coated on surface of the strontium aluminate phosphor by sol-gel method. The SrAl₂O₄∶Eu²⁺, Dy³⁺/Cu-14Al-X self-sensing composite coating with different amounts of SiO₂ coating was prepared by detonation spraying on steel 45# substrate. The emission spectra and afterglow attenuation curves of strontium aluminate powder along with self-sensing coating were compared in this paper, the corresponding friction coefficient together with wear of the composite coating were also compared, and further the effect of amount of SiO₂ coating on the luminescence and tribological behavior of the self-sensing coating was analyzed in details as well. The results show that SiO₂ coating can protect strontium aluminate during detonation spraying and improve luminous properties of the coating. With the increase of amount of SiO₂ coating, the structure of the composite coating becomes more compacted, and the hardness and wear resistance of the composite coating are improved as a consequence. Under 20% amount of the coating, the hardness of strontium aluminate powders takes 564.5HV, which is 38% higher than that of uncoated strontium aluminate powders. The friction coefficient of the composite coating after being coated is relatively stable due to a certain degree of self-lubricating effect of broken SiO₂ coating. The friction coefficient of the composite coating reaches 0.182 at 15% amount of SiO₂ coating in this case, which exhibits the best friction performance.

Key words: SiO₂ coating, self-sensitivity detection, detonation spray, friction performance