Colloidal Processes

Figure 2. Linear shrinkage versus temperature at l°C/min heating rate for silica gels prepared by three different methods a) two-step acid hydrolysis, b) two-step base hydrolysis, c) colloidal process. (Reproduced with permission from Ref. 4. Copyright 1984 Wiley- Interscience.)...

Semibatch operation safety, 21 843 Semibatch polymer colloid process, 20 376 Semibatch polymerization of vinyl acetate, 25 608 Semibatch reactors, 21 332 Semibright nickel, 9 820 Semibulk containers, 18 5-6 Semibullvalene... 

A second approach for fabricating electrode arrays has involved micromachining of silicon molds, which are filled with electrode material by colloidal processing methods. In contrast to G-MEMS, this fabrication approach is suitable for both anodes and cathodes, as one merely alters the composition of the powders. The process flow for electrode array fabrication is depicted in Figure 23. 

FIG. 1.6 A schematic diagram of colloidal processing of ceramic specimens. The figure illustrates some of the ways in which a dispersion is densified and transformed into porous or compact films or bulk objects. (Adapted and modified from Brinker and Scherer 1990.)... 

The magnetic, optical, and electrical properties of materials often depend on the microstructural details and the morphology of materials. Even if the final state is not a colloid, many products pass through colloidal processing routes prior to the final stage. The availability of methods to produce model particles allows us to study and control the desired properties of the final product. 

In Section 13.2, we begin with a closer look at one of the applications we alluded to in Vignette 1.5 in Chapter 1 (colloidal processing of ceramics) in order to gain some perspective on how interparticle forces influence the structure of a dispersion. 

Lange FF, Luther EP (1994) Colloidal Processing of Structurally Reliable Si3N4. In Hoffmann MJ, Petzow G (eds) Tailoring of Mechanical Properties of Si3N4 Ceramics. NATO ASI Series E. Vol 276, Kluwer Acad Publ Dordrecht, p 3... 

The method has been adapted to the removal of liquids from all classes of substances1 and is related to the electro-colloidal processes which have been devised for desiccating peat and other materials.2 In one process peat is packed between sheet anodes and perforated sheet cathodes so that... 

In relatively recent years the term colloidal processing has been coined to describe processing technologies in which the colloidal properties of ceramic powders are exploited. J.A. Lewis [6] comprehensively reviews colloidal processing and its potential. 

Colloidal processing of ceramic membrane supports. General introduction... 

Hidber et al. [9] described the colloidal processing of wet-milled a-alumina suspensions by centrifugal casting from a 80 wt-% suspension at pH 4.3. The mean particle diameter of the a-alumina powder was 0.3 pm and the BET surface area 8.59 m /g. Nitric acid or ammonia was used for electrostatic stabilisation. Very dense ceramics could be obtained with relative densities up to 99.9%. 

This chapter is split in two parts. The first part will briefly treat the preparation of flat ceramic membrane supports by colloidal processing. In our laboratory, these supports are used to study stability and gas separation properties of microporous silica membranes because they are easy to prepare and demand less complex testing equipment. 

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