Several Method To Improve The Microstructure And Performance Of Thermal Barrier Coatings

As the development of aerospace enterprise, the operating temperature of blade isrequired higher and higher, spraying thermal barrier coatings on the blade is widely used. Alotof problems of military service thermal barrier coatings still exist, therefore, improving theproperty and performance of the coatings is crucial to increase the service life and productiveefficiency of gas turbine.CoNiCrAlY was sprayed on Ni-based super alloy substrates by high velocity oxygen fuel(HVOF), X-ray diffraction (XRD)、Scanning electron microscopy (SEM) and energydispersive spectroscopy (EDS) were applied to analyze the phase composition、microstructureand thermal diffusion of the CoNiCrAlY coatings made by different conditions. YSZ wassprayed on CoNiCrAlY coatings by air plasma spray, test the thermal shock resistanceproperty of the coatings and analyze the results of the experiment.Study the phase composition、microstructure and thermal diffusion of the CoNiCrAlYcoatings in two details. At first, adjust the technological parameter of the spraying equipment,in this study, regulate the oxygen-fuel ratio and the nozzle diameter. Secondly，CoNiCrAlYcoatings were heated in vacuum atmosphere, then the interface between the substrate andcoatings was changed from mechanical joint to metallurgical joint. Researching on this subjecthas important practical significance to improve the coating life.Experimental results show that: the oxygen content and porosity of the CoNiCrAlYcoatings Sprayed by low oxygen-fuel radio is higher, and the thermal shock resistanceproperty is better; the higher oxygen content and porosity in the CoNiCrAlY coatings sprayedby larger nozzle diameter, and the thermal shock cycling is more than the small one;CoNiCrAlY coatings heated in the vacuum atmosphere at1120℃, the element diffusionoccurred at the interface between the substrate and the CoNiCrAlY coatings, the interface waschanged from mechanical joint to metallurgical joint, the coatings after vacuum heat treatmentshow better thermal shock resistance property.