Preparation And Properties Of Self-sensitive Luminescent Composite Coating For Detonation Spraying

The self-sensitive luminescent coating has excellent mechanical properties,wear resistance,friction reduction,corrosion resistance of high-alumina bronze alloy?Cu-14Al-X?and excellent luminescent properties of SrAl₂O₄:Eu²⁺,Dy³⁺as well as residual glow properties.It can emit continuous visible light after ex citated by ultraviolet lamp.Inspectors can use hand-held ultraviolet meter to regularly inspect the wear or corrosion of the workpiece surface,besides to protect the part body or prevent other anti-wear and corrosion functional layers from being damaged.Thermal quenching is the main factor affecting the luminescent properties of hot-pressed sintered coatings.Detonation gun spraying has low thermal effect on workpiece,which can reduce the quenching probability of strontium alu minate.In this paper,high alumina bronze coating and self-sensitive luminescent composite coatings were prepared by detonation gun spraying technology.The effects of Strontium Aluminate on the structure and mechanical properties of high alumina bronze coatings were discussed.The effects of spraying parameters on the structure,mechanical properties,luminescent properties and friction and wear properties of the composite coatings were also discussed.SrAl₂O₄:Eu²⁺,Dy³⁺is ceramic phase with high hardness relative to high alumina bronze.The structure of soft matrix+hard particles is formed in the coating.The microhardness of self-sensitive luminescent composite coatings is higher than that of high aluminium bronze coatings due to dispersion strengthening of phosphorescent particles.With the increase of oxygen-fuel ratio from 1.3 to 2.3 and spraying distance from 10 cm to 20 cm,the interfacial compatibility between strontium aluminate and high-alumina bronze increases,The bonding strength of composite coatings increased by 75%and 39%respectively.,and the deposition rate of strontium aluminate increases,which enhances the load-carrying capacity and deformation resistance of the coating,and the microhardness of the composite coatings increased by 24%and28%respectively..The analysis of luminescent performance shows that with the increase of O₂:C₂H₂ rate from 1.3 to 2.3,the volume percentage of phosphorescent particles deposited in the coating increased by 10.3%,and the volume percentage of effective phosphorescent particles deposited in the coating decreased by 5.9%.With the increase of spraying distance,the deposition rate of SrAl ₂O₄:Eu²⁺,Dy³⁺increased9.5%,and the deposition rate of effective luminescent phosphor p articles first increased and then decreased.But all are less than 30%of the doping in the mixed powder.The emission spectra of the self-sensitive luminescent composite coating are generally 400-650 nm broadband emission,impurity emission peaks were gen erated at460 nm and 480 nm,and the spectra all showed blue shift.After friction,Observed under fluorescence microscope,the distribution of phosphor particles in the grinding crack was consistent with that of the effective phosphor particles.The blue-green light visible to the naked eye can be emitted as a wear indication after being excited by ultraviolet light source.Friction results show that the addition of SrAl₂O₄:Eu²⁺,Dy³⁺increases the friction coefficient and decreases the wear rate of by 51%of the high-alumina bronze coating.The friction mechanism changes from adhesion wear to abrasive wear.With the increase of oxygen-fuel ratio from 1.3 to 2.3 and distance from 10 cm to 20 cm,the dispersion strengthening of SrAl₂O₄:Eu²⁺,Dy³⁺increases the hardness,load-carrying capacity and deformation resistance of the coating,and the wear rates were reduced by 102%and 34%respectively.The interfacial compatibility between SrAl₂O₄:Eu²⁺,Dy³⁺and high alumina bronze is enhanced,and strontium aluminate is not easy to fall off during friction,which makes the friction mechanism of the coating change from abrasive wear to fatigue wear with slight abrasive wear.