The self-sense monitoring of coating wear by in situ SiO2-coated SrAl2O4:Eu2+,Dy3+ luminescent particles

Monitoring of coating health was achieved by embedding sensor materials SrAl 2 O 4 :Eu 2+ ,Dy 3+ in tribological coatings, and luminescence spectra of sensor materials were used for damage sensing by monitoring the intensity of the spectra. When the light emitting from coating disappeared, it indicated the coating wearied off and the substrate exposed. But emission intensity of the SrAl 2 O 4 :Eu 2+ ,Dy 3+ in tribological coating was quenched in preparation process which will weaken the effect of coating instructions. In this work, SiO 2 -coated SrAl 2 O 4 :Eu 2+ ,Dy 3+ were coupled with Cu-14Al-X alloy powders to form sensor composite coating by supersonic plasma spraying. The composite coatings before and after SiO 2 -coating were compared of phase composition, microstructure, luminescence properties and tribological performance. The composite coating shows not only good resistance to wear but also exhibits strong green light emitting under UV light. The SiO 2 -coating could prevent phosphors quenching due to high temperature in the supersonic plasma spraying process, and could repair the wear surface. The composite coating with SiO 2 -coated SrAl 2 O 4 :Eu 2+ ,Dy 3+ particles had very stable friction coefficient, When the coating ratio of SiO 2 was 10% for SrAl 2 O 4 :Eu 2+ ,Dy 3+ particles, the luminescent properties and friction property of composite was optimal.