Deposit porosity

Thus the key parameters influencing the corrosion rate under deposits will be the deposit porosity, which determines the available surface area of material for corrosion, and the deposit tortuosity, which along with porosity will modify the fluxes of diffusing species within pores. Readers interested in a more extensive discussion are referred to other sources (17). Here we concentrate on a brief discussion of electrochemical methods of investigating the properties of deposits as a basis for eventual modeling. 

Postdepositional processes resulted in a quite significant modification of depositional porosity. In addition to compaction, carbonate and clay mineral cementation is the major porosity reducing factor. 

Macae calcarenite volume (75%)= 1.8 x 10 m Calcilutite depositional porosity = 60% (Ginsburg, 1956 ... 

Calcarenite depositional porosity = 40% (Enos Sawatsky, 1979, 1981 Halley Harris, 1979 apud Scholle Halley, 1985)... 

Key words Solid Oxide Fuel Cells/Electron Beam Deposition/Porosity/Zirconia Ceramics... 

The deposit permeability can also be calculated using the Carman-Kozeny equation, when particle shape and deposit porosity are known ... 

However, this method presents two main limitations. First it is only applicable on a transparent module and second it is not possible to directly measure the deposit porosity. Thus, in parallel another method which would overcome those drawbacks and bring complementary information was investigated. 

The second method uses acoustic waves. It gives information about the deposit porosity and can be used with a nontransparent module. With this method, it is also possible to follow the deposit kinetics. This method has to be calibrated because of the lack of knowledge about the theory of acoustic waves propagation in porous media. Thus, the common use of both methods on the same module will enable complementary information about the deposit to be obtained. 

Flame spraying is noted for its relatively high as-deposited porosity, significant oxidation of the metallic components, low resistance to impact or point loading, and limited thickness (typically 0.5 to 3.5 mm). Advantages include the low capital cost of the equipment, its simplicity, and the relative ease of training the operators. In addition, the technique uses materials efficiently and has low associated maintenance costs. 

The depositional porosity of shale is normally higher than that of sand. 

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