| Abstract: |
Plasma sprayed coatings based on Cr2O3 have good technical characteristics. They have no phase changes to the melting point, they are dense, they have high hardness, they have good wear resistance and also good corrosion against most acidic and alkalic solutions resistance. The paper presents characterization of thick Cr2O3 and Cr2O3-5SiO2-3TiO2 coatings and freestanding plates produced by water stabilized plasma (WSP) gun. The reported results include coating density and porosity values, microstructure, coefficient of thermal expansion (CTE), thermal diffusivity and thermal conductivity, abrasion wear resistance, hardness, and Young?s modulus. The properties, like hardness and CTE, of the coatings produced with WSP were principally similar to the properties of APS sprayed coatings. Porosity of coatings was around 7%, which is little higher than porosity of APS sprayed Cr2O3. Main difference was in the results of abrasion wear test. Weight losses of WSP coatings were higher than APS sprayed coatings. That can be explained by the size of lamellae, which are larger in WSP coatings due to larger powder particle size. In wear tests material removal occurs by the peeling off of lameallae, so weight loss is higher with larger lameallae.
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