Sintered metal components

ITottinen et al. [44,45] used htanium sintered meshes as DEs on the cathode side of a PEMEC because the porosity of these metal sheets does not reduce when in compression. It was demonstrated that in order ter the cell to achieve the required performance, the sintered meshes had to be coated with platinum. However, the results showed that a cell with CEP (SIGRACET GDEIO-BB) as the DE shll performed slightly better (especially at high current densities) than the cell with the Pt-coated sintered Ti mesh. Cisar et al. [46 presented another example in which a DE consisting of sintered metal fibers was used on the cathode side of a PEMEC. Once put together, these fibers were rmified or bonded to the EE plate (made out of metal) in order to combine the two components into one. 

Most of the industrial metallic catalysts are metals on carrier. The main purpose of using a carrier is, of course, to achieve high dispersion of the metal component and to stabilize this form of metal against a spontaneous sintering. However, in important reactions (like reforming of hydrocarbons) a metal support is not inert and the overall reaction is actually an interplay of the two functions that of the metal and that of the catalytically active carrier. Moreover, some other effects may also play a role ... 

Most analyzer sampling systems require a filter with at least one wire mesh strainer (100 mesh or finer) to remove larger particles that might cause plugging. Available filter materials include cellulose, which should only be considered if it does not absorb the components of interest. Sintered metallic filters can remove particles as fine as 2 ym, cellulose filters can remove down to 3 /on, and ceramic or porous metallic elements can trap particles of 13 ym or larger. When the solids content is high, two filters can be installed in parallel with isolation valves on each. Motorized self-cleaning filters are also available for such services. 

Sintered metals show a strong correlation between open porosity and effective gap. (The effective gap weS of a flameproof component is the highest MESG (Maximum Experimental Safe Gap) value of combustible gas mixtures (see Section 1.2.2), for which that component ensures flameproofness. For gas mixtures with MESG < wen, flame transmission occurs.) (see [19]). 

To overcome these difficulties, printable compositions were formulated. The printable sensor inks contained three major components the metal oxide, glass frit for adhesion, and organic vehicles that burn off during firing. A catalyst, in the form of a precious metal chloride, was applied and fired on the sintered metal oxide layer alternatively, precious metal resinate solutions were incorporated directly into the ink. Initial tests of these printable layers demonstrated sensor resistivities that changed rapidly and reversibly by as much as a factor of 14. The response time was a few seconds while recovery took about 1 min, although complete recovery was often longer than 16 h. 

In membrane-separation processes, a feed consisting of a mixture of two or more components is partially separated by means of a semipermeable membrane through which one species moves faster than the others. That part of the feed that passes through the membrane is called the permeate, while the portion that does not pass is called the retentate. The membranes may be thin layers of a rigid material such as porous glass or sintered metal, but more often they are flexible films of synthetic polymers prepared to have high permeability for certain types of molecules. 

Consider cases (a) and (b) of problem 8. Some separate studies of deactivation in this system indicate that the rate of deactivation is independent of the concentration of reactants or products, but is proportional to the second power of activity itself, with an half-life of 20 h. (Second-order kinetics, independent of concentrations, are often a sign of decay via sintering of the metallic component of the catalyst—here Pt on AI2O3). 

Sve] Svensson, L.E., Engstroem, U., Improved Precision of Sintered Steel Components Made from Partially Prealloyed Copper-Iron Powders , Powder Metall, 22(4), 165-174 (1979) (Morphology, Experimental, Phys. Prop., 11)... 

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