Research On Preparation And Characterristics Of NiCoCrAlY Cladded Coating Reinforced By Rare-rarth CeO₂Powder

A novel idea to improve the properties of NiCoCrAlY cladding coating was carried out byintroducing different particle sizes of rare-earth CeO2for studying their influences on the coating s’characteristics.The major work done and the results obtained are as follows:1. Dispersion behaviors of different particle size level CeO2powders (including20nm,200nm,500nm and5μm) in volume ration of1:1ethanol-water suspension by using of both the ball-millingand the ultrasonic were studied by investigating their particle size distribution, surface potential anddispersion stability.2. Dispersion behaviors of CeO2with micron size in different volume ratios of ethanol-watersuspension by using of both the ball-milling and ultrasonic were studied to find out its suitabledispersion medium and method. And the strengthening mechanism of dispersion property for thewater composite was studied by comparing the ball-milling dispersion, watering after the ball-millingdispersion, the composite dispersion and the water composite dispersion.3. Based on the fluent finite element software, the flow field simulation of ball-milling dispersionprocess was studied. And the index of grinding chamber pressure was introduced to evaluate theball-milling dispersion in order to obtain the effects of ball mill speed, the ration of grinding ball andmaterial, the fill rate of grinding chamber on their pressures, and the simulation results were provedby an orthogonal experiment of20nm CeO2powders in the volume ratio of1:1ethanol-watersuspension by using of the ball-milling dispersion.4. The additive amount of different particle size CeO2powders were confirmed by combiningboth the theory method and the experiment method, the cladding coatings with both a completesurface profile and no internal hole were prepared by optimizing the laser parameter, and the influenceof different particle size CeO2powders on their structure, micro hardness and high temperatureoxidation resistance was studied to reveal the refinement mechanism of CeO2to the cladding coating.