Atmospheric plasma spraying

Vassen R, Hathiramani D, Mertens J, Haanappel VAC, and Vinke IC. Manufacturing of high performance solid oxide fuel cells (SOFCs) with atmospheric plasma spraying (APS). Surf. Coat. Technol. 2007 202 499-508. 

Atmospheric Plasma Spray (Triplex APS). These deposition techniques will be used within this project to deposit the various layers in planar SOFC. 

The other important factor to affect the operational conditions of the cell is the voltage increase between the carbon and copper lead. This problem has been solved individually in industry. For example, a 250 pm thick layer of nickel can be coated onto the upper part of the carbon anode using the atmospheric plasma spraying method.7 This electrode has been operated at 15 to 17 A dm-2 in a 1000 A scale industrial cell for 19 months. The cell voltage was 9.5 V and polarization did not occur with this electrode. Characteristic points of this new carbon electrode are low polarizability and no anode effect, and the concentration of carbon tetrafluoride contaminating the fluorine is below 2 ppm. 

Several methods effectively apply thin coatings to substrates. One process commonly employed for TBC fabrication is thermal plasma spraying. For this technique, the bond coat is deposited with low-pressure plasma spraying, and the Zr02 top coat is then created using atmospheric plasma spraying.A potential problem with this method is coating fracture due... 

Thickness of APS (atmospheric plasma spraying) coating can be selected between 50 and 250 pm, depending on application however, novel deposition techniques such as suspension or solution plasma-spraying allow coatings with thickness <10 pm. 

Figure 5.32 SEM images of conventional atmospheric plasma sprayed (APS, left) and suspension plasma sprayed (SPS, right) hydroxyapatite coatings, (a, b) Top view and (c, d) coating cross-sections (Gross and Saber-Samandari, 2009). ( With permission by Elsevier.)...

Table 6.6 Phase contents of atmospheric plasma-sprayed calcium phosphate coatings after immersion in protein-free SBF (HBSS, Table 7.8) for 12 weeks (in mass%) (Figure 6.2d —f).

A notable exception is a study by Hesse et al. (2008) who investigated the effect of powder grain size and grain size distribution on the spatial distribution of calcium phosphate phases in atmospheric plasma-sprayed hydroxyapatite coatings incubated in r-SBF (SBF-H, Table 7.8). Coatings were mechanically abraded under dry conditions in steps of 40 pm by abrasive SiC paper, and the newly created surfaces analysed by XRD with Rietveld refinement for their quantitative phase composition. The results of this depth profiling are shown in Figure 6.8. 

Figure 6.17 Formation of a thin CaSi03 (or CaTiSi05) reaction layer adjacent to the titanium alloy substrate surface of an atmospheric plasma-sprayed Ti6AI4V...

Heimann, R.B. and Wirth, R. (2006) Formation and transformation of amorphous calcium phosphates on titanium alloy surfaces during atmospheric plasma spraying and their subsequent in vitro performance. Biomaterials, 27, 823-831. 

Park, E. and Condrate, R.A. (1999) Graded coating of hydroxyapatite and titanium by atmospheric plasma spraying. Mater. Lett., 40, 228-234. 

Figure 7.3 Dependence of HAp coating crystallinity and thermal decomposition on standoff distance during atmospheric plasma spraying, (a) Stand-off distance 80 mm. (b) Standoff distance 150 mm. (Adapted from Vilotijevic et al. (2011). With permission by Elsevier.)...

Lu H, Qu Z, Zhou YC (1998) Preparation and mechanical properties of dense polycrystalline hydroxylapatite through freeze-drying. J Mater Sci Mater in Med 9 583-587 Lugscheider E, Weber Th, Knepper M (1991a) Production of biocompatible coatings by atmospheric plasma spraying. Mater Sci Eng 139A 45-48... 

Lugscheider E, Weber Th F, Knepper M (1991b) Processabihty of fiuorapatite through atmospheric plasma spraying technology. Metalloberfiache 45 129-132... 

Controlled atmosphere plasma spray, which also inclndes inert gas shrouded plasma... 

Reprinted with permission from Vend, A., Mrdak, M., Cvijovic, I., 2006. Microstructures and trihological properties of ferrous coatings deposited hy APS (Atmospheric Plasma Spraying) on Al-alloy substrate. FME Trans. 34, 151—157 Leeuwenburgh, S., Wolke, J., Schoonman, J., Jansen, J., 2005. Influence of deposition parameters on chemical properties of calcium phosphate coatings prepared by using electrostatic spray deposition. J. Biomed. Mater. Res. A 74,275—284. 

Vend, A., Mrdak, M., Cvijovic, I., 2006. Microstmctures and tribological properties of ferrous coatings deposited by APS (Atmospheric Plasma Spraying) on Al-aUoy substrate. FME Trans. 34, 151-157. 

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