Coated particles 446 Subject

If the adhesion mechanism between particles with different size is mainly subject to this attraction due to the electrostatic interaction, it is deduced that the increase in the ratio of core particle size to the coating particle size is advantageous for the formation of the monolayer particle coated powder. 

Lin and He (2005) have compared the role of eleetroless (EL) NiP composite coatings incorporated with micron- and nanosized SiC partieles on the cavitation erosion of AISI1045 steel. The EL Ni-P-nano SiC and Ni-P-micro SiC composite coatings were prepared by dispersing nano (25-50 mn) and micron- (5 pm) sized particles in an acidic hypophosphite-reduced EL nickel plating bath maintained at 90 1°C. The deposition time was 3 h and the coating thickness was 60 pm. All the coatings were subjected to post heat-treatment to achieve abetter hardness and wear... 

All AB, alloys are very brittle and are pulverized to fine particles in the hydrid-ing-dehydriding process (see Sec. 7.2.1). Thus electrodes must be designed to accommodate fine powders as the active material. There are several methods of electrode fabrication Sakai et al [35] pulverize the alloy by subjecting it to several hydrogen absorption-desorption cycles, before coating the resulting particles with Ni by chemical plating. The powder is mixed with a Teflon dispersion to obtain a paste which is finally roller-pressed to a sheet and then hot-pressed to an expanded nickel mesh. The fabrication of a simple paste electrode suitable for laboratory studies is reported by Petrov et al. [37],... 

FIG. 12 SEM pictures of LB monolayers of particles 2 on a glass support, deposited from an aqueous solution containing disodium tetrachloropalladate (cone. 10 mol L and subsequently immersed in a plating bath for electrodeless nickel deposition for (a) 15 and (b) 40 sec. Typical SEM pictures of particle monolayers not subjected to nickel coating are shown in Figure 9. (From Ref. 156.)... 

Yu et al. [139] developed a dry-deposition technique for coating the MPL onto a diffusion layer. This method consisted of forcing a mixture of carbon and PTFE powder through a mesh with the help of a vacuum pump located underneath the DL material. Once the mixture passed through the mesh, it was deposited on the surface of fhe substrate (still with the help of the vacuum pump). After this, the DL, with the MPL, was sintered at 350°C in order to melt the PTFL particles and bind all the particles together. Once the thermal stage was completed, the MPL was subjected to a rolling step in order to adjust the total thickness of the layer (MPL and DL). 

Precipitation of the coating from aqueous solutions onto the suspended Ti02 particles. Batch processes in stirred tanks are preferred various compounds are deposited one after the other under optimum conditions. There is a very extensive patent literature on this subject. Continuous precipitation is sometimes used in mixing lines or cascades of stirred tanks. Coatings of widely differing compounds are produced in a variety of sequences. The most common are oxides, oxide hydrates, silicates, and/or phosphates of titanium, zirconium, silicon, and aluminum. For special applications, boron, tin, zinc, cerium, manganese, antimony, or vanadium compounds can be used [2.40], [2.41],... 

Since the pigments are subjected to considerable thermal stress during this conversion, the FeOOH particles are stabilized with a protective coating of silicates [5.5], phosphates [5.6], chromates [5.7], or organic compounds such as fatty acids [5.8]. 

The measurement of FPN from the N03 recovered from a backup Teflon-nylon or nylon filter with the ADM is subject to some of the same potential sources of error as with the DDM. No loss of FPN passing through the annular denuder is expected on the basis of particle-loss measurements (55). Although HONO is efficiently removed ahead of the filter or filters, nearly all of the PAN would reach the nylon filter. Retention of PAN on nylon filters has been reported to be insignificant. Thus, relatively little error in FPN is expected with the ADM and CO -glycerol coated denuders. 

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