Processing methods slurry coating

In application of the method, care should be taken not to change the properties of the active phase (or its precursor) in the process of slurry dip-coating, and attention should be paid to the adhesion of the coated layer. Encapsulation of the active phase may occur, which reduces the availability of the active phase. An attractive feature of slurry dipcoating is that it enables depositing of a synthesized active phase or a support material with known properties on a monolith surface. When the active phase or its precursor is difficult to synthesize or is prepared under conditions that may damage the support (e.g., perovskite) [88,94], the method is very useful. 

Another Ni-based solid oxide fuel cell (SOFC) electrode was developed on which a YSZ (yttria-stabilized zirconia) cermet and Lanthanum chromite were deposited by a slurry coating method. It was also suggested that a plasma spraying process can be used for the cermet deposition on the electrodes. The following reactions are expected to take place in a fuel cell employing a natural gas source, where internal reforming takes place on the Ni-YSZ electrode ... 

To add surface area, the supports are uniformly coated with a slurry of gamma-alumina and recalcined under moderate conditions. The wash coat acts to accept the active metals, typically low levels of platinum and palladium, in a conventional impregnation process. In the United States in passenger car apphcations the spherical catalyst is used almost exclusively, and methods have been developed to replace the catalyst without removing the converter shell when vehicle inspection reveals that emission standards are not met. 

The slurry process has been enhanced with vacuum to fabricate planar SOFCs [78], This method is of low cost and thus has been widely used to develop low-cost SOFCs. However, together with other liquid precursor methods such as sol-gel and spray pyrolysis, it is time, labor, and energy intensive because the coating-drying-sintering has to be repeated in order to avoid cracking formation. 

The vacuum evaporation process and polymer slurry process are quite new relative to the others and have the potential to provide more control in the processing, in the case of the vacuum evaporation technique, or greatly reduce the cost and environmental concerns of pack aluminizing with the polymer slurry methods. The vacuum evaporation process allows one to diffuse other elements than A1 into the steels or to deposit FeAl coatings directly onto the surface of the steels, with A1 diffusion occurring to help bond the deposited coating. ... 

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