Influence of Particle Size on Microstructure and Properties ofAl2O3 Coatings Deposited by Plasma Spraying

摘要

In the present study, Al2O3 coatings were deposited by plasmaspraying using feedstock of different particle sizes. The effectsof particle size on their velocity and temperature in the plasmajet, the microstructure and properties of the coatings wereinvestigated. The results revealed that in view of the smallerinertia effects and lower heat capacity, the smaller particlescan be easily accelerated and heated, and have higher in-flightvelocity and temperature, which contributed to produce adenser coating with lower porosity and higher mechanicalproperties. It was also found that the coating deposited usingthe finest starting powder has the lowest thermal diffusivity.This may be reasonably correlated with the microstructuralcharacteristics. In addition, the coating manufactured using theintermediate feedstock in terms of particle size (D50 of 19.3μm)exhibited the highest wear resistance.