Characterization of the Near-Eutectic Al₂O₃-40Â wt% ZrO₂ Composite Coating Fabricated by Atmospheric Plasma Spray. Part II: Microstructure and Mechanical Properties of Nanocomposite Coating

摘要

Near-eutectic Al₂O₃-40wt% ZrO₂ coating composed of nano-polycrystalline structure with grain size of 20-50 nm and amorphous phase was deposited by atmospheric plasma spray (APS) using nano-sized powders obtained by sol-gel technique as feedstock. The phase composition and microstructure of as-sprayed coating were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), and high resolution transmission electron microscopy (HRTEM). Meanwhile, some mechanical properties such as micro hardness and cohesion of as-sprayed coating were also studied. The results revealed that the as-sprayed coating consisting of α-Al₂O₃, γ-Al₂O₃, and metastable t-ZrO₂ was obtained with lower porosity about 7% and average microhardness of 726 kg/mm2 with higher Weibull modulus 16 as compared to the recently reported coating with the same composition. Furthermore, the results from a comparative study in scratching test indicated the present coating exhibited a higher cohesion than that of pure Al₂O₃ coating and Al₂O₃-40 wt% ZrO₂ coating using spray-dried agglomerated powders as feedstock.View full textDownload full textKeywordsAtmospheric plasma spray, Coating, Cohesion, Near-eutectic, FeedstockRelated var addthis_config = { ui_cobrand: "Taylor & Francis Online", services_compact: "citeulike,netvibes,twitter,technorati,delicious,linkedin,facebook,stumbleupon,digg,google,more", pubid: "ra-4dff56cd6bb1830b" }; Add to shortlist Link Permalink http://dx.doi.org/10.1080/10426914.2011.551951