Spray pyrolysis coatings produced

Spray pyrolysis has been utilized to produce both powders of SOFC materials [19] and also SOFC component layers [118-121], Thin (1 pm) coatings have been fabricated by spray pyrolysis [121], with zero gas permeability achieved for some conditions of substrate surface roughness and temperature during deposition, but... 

FIGURE 6.15 Coatings produced by spray pyrolysis, (a) NiO-SDC anode layer and SDC electrolyte layer and (b) closeup of electrolyte layer showing SDC layer thickness of approximately 1 pm and fully dense SDC microstructure [121]. 

However, the generation of thin palladium membranes onto ceramic surfaces is more complicated. Methods such as spray pyrolysis (see also Section 4.1.3), chemical vapour deposition and sputtering are used. Another method commonly applied [400] is electroless plating [408]. Palladium particles are produced from palladium solution containing amine complexes of palladium in the presence of reducing agents. Palladium nuclei need to be seeded onto the surface prior to the coating procedure [408]. Ceramic surfaces such as a-alumina are first sensitised in acidic tin chloride and then palladium is seeded from acidic palladium ammonia chloride [408]. 

The technique of spray pyrolysis can be used to obtain both, dense or porous oxide films, and to produce ceramic coatings and powders. Compared to other deposition techniques, spray pyrolysis is a simple method for operational control. It is also cost-effective, especially regarding the cost of system implementation. Furthermore, deposition in multi-layers can be easily obtained by this versatile technique. 

The application oiflame spray pyrolysis to NP synthesis generally resulted in the production of metal oxides and salts [54—57]. Recently, Athanassiou et al. proposed the use of a flame-SP apparatus which operated in continuous fashion in a nitrogen-filled glovebox to produce carbon-coated Cu NPs with a good size uniformity [58]. 

Biomedical. Heart-valve parts are fabricated from pyrolytic carbon, which is compatible with living tissue. Such parts are produced by high temperature pyrolysis of gases such as methane. Other potential biomedical apphcations are dental implants and other prostheses where a seal between the implant and the living biological surface is essential. Plasma and arc-wire sprayed coatings are used on prosthetic devices, eg, hip implants, to achieve better bone/tissue attachments (see Prosthetic and BiOLffiDiCALdevices). 

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