Investigations of Wettability of Wear Resistant Coatings Produced by Atmospheric Plasma Spraying

2017 ◽  
Vol 270 ◽  
pp. 230-235 ◽  
Author(s):  
Pavel Komarov ◽  
Ladislav Čelko ◽  
David Jech ◽  
Martin Papula ◽  
Karel Slámečka ◽  
...  
Keyword(s):  
Contact Angle ◽  
Plasma Spraying ◽  
Liquid Droplet ◽  
Critical Role ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Metallographic Analysis ◽  
Water Contact ◽  
Wear Resistant ◽  
Wear Resistant Coatings

Changes in fluids contact angle in the interaction with materials surface can play a critical role in enhancement of hydro-machine components and pipelines efficiency and/or service lifetime. However most nowadays used materials and/or coatings are made from polymers or ceramic polymer composites produced by highly sophisticated and/or very expensive techniques. Unfortunately there are a lack of mechanical properties. With the aim to study the role of the surface topography on the water contact angle changes, the representatives of wear resistant coatings (WC10Co4Cr, Cr2O3+5SiO2+3TiO2and Al2O3) were produced by means of atmospheric plasma spraying. Wettability of the coatings surface was studied by adding the liquid droplet on as sprayed, grinded and polished coating's surface by measuring the changes of its contact angle. To estimate the coatings phase composition and topography XRD technique and optical profilometer were used. The contact angle of water was measured by sessile droplet method. To obtain the complex information of the cross-sectional coatings microstructure the conventional metallographic analysis approaches and optical microscopy were also used.

Effects of 316SS addition on the properties of the coatings based on Al2O3 applied by plasma spraying

2018 ◽  
Vol 52 (19) ◽  
pp. 2597-2608
Author(s):  
Amal Chebbi ◽  
Vincent Guipont ◽  
Khaled Elleuch ◽  
Michel Jeandin
Keyword(s):  
Plasma Spraying ◽  
Composite Structures ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Lamellar Microstructure ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Wear Resistant Coatings ◽  
Dense Microstructure ◽  
Carrier Gases

Ceramic plasma-sprayed coatings are successfully used for prolonging the service life of industrial components where high wear and corrosion resistance are required. In this work, various types of coatings based on alumina were deposited by atmospheric plasma spraying on 304 L austenitic stainless steel substrate. These coatings were used in further tribological studies. For the atmospheric plasma spraying applications, spraying parameter choices such as carrier gases, plasma enthalpy, current intensity, spraying distance, and particles granulometry are the key issues. Two kinds of Al2O3 particle sizes 2–12 µm (Amperit) and 15–45 µm (Norton) were used to prepare pure and composite coatings. The spraying distance was varied from 90 mm to 120 mm. Microstructure characterization performed by scanning electron microscopy showed that the Amperit powders projected at a distance of 90 mm provided better cohesion and a more dense microstructure. However, the choice of the spraying distance of 120 mm was defined to manufacture composite structures, which allowed more stability in the plasma jet and enabled large metal particles to be mixed with ceramics. To develop hard and wear-resistant coatings, alumina and 316SS were mixed with different addition rates by volume (Al2O3–5 vol.%316SS and Al2O3–25 vol.%316SS) and fed through a single injection port. Composite coatings include porosity and unmolten particles in a lamellar microstructure. The addition of 316SS powder led to the formation of typical layered structure due to the effect of viscosity and different densities of the two particles. These coatings were investigated by different tests to evaluate microhardness, cohesion, and fracture values of such materials. Despite the significant decrease in the microhardness values, the 316SS particle addition demonstrates an improvement in the toughness and crack resistance.

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