Classification of Coatings

or Y have specialized applications for wear and high-temperature oxidation resistance [7, 8], 

For sacrificial coatings (e.g., zinc, cadmium) and, in certain environments, also aluminum and tin on steel, the direction of galvanic current through the electrolyte is from coating to base metal as a result, the base metal is cathodically protected (Fig. 14.1). As long as adequate current flows and the coating remains in electrical contact, corrosion of the base metal does not occur. The degree of 

The area of base metal over which cathodic protection extends depends on the conductivity of the environment. For zinc coatings on steel in waters of low conductivity, such as distilled or soft waters, a coating defect about 3 mm (1/8 in.) wide may begin to show rust at the center. However, in seawater, which is a good conductor, zinc protects steel several decimeters or feet removed from the zinc. This difference in behavior results from adequate current densities for cathodic protection extending over a considerable distance in waters of high conductivity, whereas cathodic current densities in waters of low conductivity fall off rapidly with distance from the anode. 

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Table 13.11 Cluster classification of coatings for use in a QCM sensor array...

To compare various materials independent of their layer thickness, R. G. Gordon proposed a classification of coatings by a figure of merit, defined as the ratio of its conductivity and its visible absorption coefficient o/a = - Rj,q ln(T + R) 1. For high quality ITO and for AZO values of 4 to 5 were determined. From Figure 10.20 the values for ITO on PET, PEDOTPSS, and in situ PEDOT were extracted to be 0.5,0.1, and 0.03 Q", respectively. 

Classification of the many different encapsulation processes is usehil. Previous schemes employing the categories chemical or physical are unsatisfactory because many so-called chemical processes involve exclusively physical phenomena, whereas so-called physical processes can utilize chemical phenomena. An alternative approach is to classify all encapsulation processes as either Type A or Type B processes. Type A processes are defined as those in which capsule formation occurs entirely in a Hquid-filled stirred tank or tubular reactor. Emulsion and dispersion stabiUty play a key role in determining the success of such processes. Type B processes are processes in which capsule formation occurs because a coating is sprayed or deposited in some manner onto the surface of a Hquid or soHd core material dispersed in a gas phase or vacuum. This category also includes processes in which Hquid droplets containing core material are sprayed into a gas phase and subsequentiy solidified to produce microcapsules. Emulsion and dispersion stabilization can play a key role in the success of Type B processes also. 

FIG. 20-71 Classification of agglomeration processes by agitation intensity and compaction pressure. Relative density is with respect to primary particle density and equals (1 — e) where e is the solid volume fraction. Reprinted from Granulation and Coating Technologies for High-Value-Added Industties, Ennis and Litster (1996) with permission of E G Associates. All rights reserved. 

In Section 13.2, we introduce the materials used in OLEDs. The most obvious classification of the organic materials used in OLEDs is small molecule versus polymer. This distinction relates more to the processing methods used than to the basic principles of operation of the final device. Small molecule materials are typically coated by thermal evaporation in vacuum, whereas polymers are usually spin-coated from solution. Vacuum evaporation lends itself to easy coaling of successive layers. With solution processing, one must consider the compatibility of each layer with the solvents used for coating subsequent layers. Increasingly, multilayered polymer devices arc being described in the literature and, naturally, hybrid devices with layers of both polymer and small molecule have been made. 

Bender KS, C Shang, R Chakraborty, SM Belchik, JD Coates, LA Achenvach (2005) Identification, characterization, and classification of genes encoding perchlorate reductase. J Bacterial 187 5090-5096. 

The change in the toxicological classification of lead- and chromate-based anticorrosive pigments has resulted in reappraisal of the formulation of anticorrosive coatings. 

Bacteria 2. See also Specific genus and species acetic acid 8 aerobes 10 anaerobic 8 autotrophic 8 binding to cells 186 branched fatty acids of 381 chemoheterotrophic 7,8 chemolithotrophic 7 classification of 6-8 coats 431 composition of 31 electron micrograph of 4 flagella 6... 

Lignite Coal. A brownish-black coal that is intermediate in coalihcalion between peat and sub-bituminous coal consolidated coal with a calorific value less than 8,300 Btu per pound (4615 Calories/kg), on a moist, mincial-matter-free basis. Synonyms include brown lignite and brown coat. Further classifications of lignite are made on the basis of calorific value ... 

The dissolution controlled release matrix systems provide sustained release profiles i.e., the active drugs in these systems are released continuously at a slow rate to provide a long-term therapeutic effect. Unlike diffusion controlled release coated systems, release profiles from dissolution controlled release coated systems do not follow zero-order kinetics but fall within the classification of delayed release systems,4 pulsatile or repeat-action systems,5 and sustained release systems.3... 

Core-based optodes, such as hollow fibers, and direct and coating-based evanescent wave spectroscopic optodes are included in the classification of absorption-type sensors. 

Classification of corrosion inhibition mechanisms such as interface inhibition, interphase inhibition, intraphase inhibition and precipitation coating (Corrosion 88, Paper 155)... 

Contacting mixtures of oxidizers and red phosphorus are used for the classification of dangerous properties of oxidizers. The properties of the red phosphorus used in these tests are also important. The author et al. have retained it in desiccators with silica gel prior to use. We did not have any concern about its particle size, because it is relatively soft and is rubbed on the steel rollers to coat them. However it has been found that the properties of the red phosphorus also influence the measured results. 

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