Sintering metallic powders

Fig. 14. Cross-sectional schematics of electrically heated catalyst (EHC) for emission control (a) extmded sintered metal powder EHC (160) (b) two...

The lowest temperature is reached in the mixing chamber (MC) where the experiments are placed (sometimes inside, see Section 6.5) and where there is the interface between the concentrated and the diluted phase. The MC is in most cases made of Cu. The internal wall of the MC are covered with a sintered metallic powder (Ag or Cu) to reduce the thermal resistance Rk (see Section 4.4) between the liquid mixture of He and the walls. 

Examples of computer reconstructed DPF porous media are given in Fig. 5 and encompass all currently available filtration media extruded ceramic filters (including reaction formed media as cordierite and grain-sintered media as SiC), fibrous filters, foams and sintered metal powder/wiremesh. 

Modem bilayered catalysts have a mechanically strong and gas-permeable support. It may be a sheet of sintered metal powder or a tube made from a heat- and corrosion-... 

Mineral membranes are obtained by sintering metal powders or stainless steel filaments with diameters between 1.5 and 80 pm [17—19]. They can be more expensive than ceramic membranes, and are hmited in selection by their pore size range. Organo-mineral membranes are hybrid membranes, e.g., UF organo-mineral membranes are composed of a polymeric matrix (mosdy PS) in which zirconia grains are dispersed finely as a filler material. The organo-mineral membranes have a considerably higher flux than traditional polymeric membranes. 

Cartridge filters are used widely throu out process industries in the clarification of liquids. The media used include yams, papers, felts, binder-fi ee and resin-bonded fibres, synthetic fibres, woven wire, sintered metal powders and fibres, ceramics, etc. The inclusion of membraneous materials. Chapter 10, in cartridge constructions has extended the range of application of these ubiquitous dements so that partides firom approximate 500 pm down to 0.1 pm are separated. 

The properties more typical for media prepared from sintered metal powders are shown in Table 2.19. These are made from powders of graded spherical particles, with sizes typically in the range 0.5-100 pm, which are compressed and sintered in moulds. A range of shapes of media can be produced, which can be subsequently worked in similar way to other metal fabrications. Cylinders, tubes and sheets are commonly used in filtration... 

Wire mesh square weave Wire mesh Dutch twill Sintered metal powder Random metal fibers... 

There are a number of different filter materials. Wire screens are the most common. Several t5 es of wire screens are available, such as the square mesh with plain weave and the square mesh with Dutch twill. There are also depth filtration media, such as sintered metal powder and random metal fibers. Advantages and disadvantages of different filter materials are shown in Table 1. 

Sintered Electrode An electrode construction in which active materials are deposited in the interstices of a porous metal matrix made by sintering metal powder. 

The shorter life of sintered fiber elements in comparison to the etched disk element is compensated for by a significantly lower cost per element. Sintered metal fiber elements in amine service are typically rated at 10 microns absolute (Clark, 1996). Since these systems are completely automated, operator acceptance problems are avoided. A sintered metal fiber element housing for amine filtration service is depicted in Figure 3-26b. PTl Technologies of Newbury Park, CA, manufactures sintered metal fiber filters for amine service, while Pall Well Technologies. Inc. of East Hills. NY. makes similar automatic sintered metal powder and sintered metal fiber filters for amine service. Pall also markets an automatic backflush amine filter which uses non-mctallic filter elements (Calhcart. 1996). 

G. C. Kuczynski, Self Diffusion in Sintering Metal Powders, Trans. AIME 185 169 (1949). 

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