Surface layers preparation

Lugovy, M., Orlovskaya, N., Berroth, K., Kuebler, J., Analysis of layered composite with crack deflection controlled by layer thickness, in Proceedings of NATO AST Functional Gradient Materials and Surface Layers Prepared by Fine Particle Technology, Kiev, Ukraine, 18-28 June 2000, ed. M.-I. Baraton and I. Uvarova, NATO Science Series, II, Mathematics, Physics and Chemistry, 16, Kluwer Academic Publishers, 273-280, 2001. 

Baraton, Marie-Isabelle, and Irina Uvarova. Functional Gradient Materials and Surface Layers Prepared by Fine Particles Technology. Vol. 16 of Mathematics, Physics, and Chemistry. NATO Science Series, ser. II. Boston Kluwer Academic Publishers, 2001. 

Kiv AE, Maximova TI, Soloviev VN (2001) MD simulation of the ion-stimulated processes in Si surface layers. In Baraton Ml, Uvarova IV (eds) Functional gradient materials and surface layers prepared by fine particles technology. Kluwer, Dordrecht, The Netherlands, pp 297-303... 

There are, however, continuing difficulties for catalytic appHcations of ion implantation. One is possible corrosion of the substrate of the implanted or sputtered active layer this is the main factor in the long-term stabiHty of the catalyst. Ion implanted metals may be buried below the surface layer of the substrate and hence show no activity. Preparation of catalysts with high surface areas present problems for ion beam techniques. Although it is apparent that ion implantation is not suitable for the production of catalysts in a porous form, the results indicate its strong potential for the production and study of catalytic surfaces that caimot be fabricated by more conventional methods. 

Plastic laminated sheets produced in 1913 led to the formation of the Formica Products Company and the commercial introduction, in 1931, of decorative laminates consisting of a urea—formaldehyde surface on an unrefined (kraft) paper core impregnated with phenoHc resin and compressed and heated between poHshed steel platens (8,10). The decorative surface laminates are usually about 1.6 mm thick and bonded to wood (a natural composite), plywood (another laminate), or particle board (a particulate composite). Since 1937, the surface layer of most decorative laminates has been fabricated with melamine—formaldehyde, which can be prepared with mineral fiUers, thus offering improved heat and moisture resistance and allowing a wide range of decorative effects (10,11). 

The micrographs in Fig. 7.88 show clearly how from a knowledge of the AG -concentration diagrams it is possible to select the exact reaction conditions for the production of tailor-made outermost surface phase layers of the most desired composition and thus of the optimum physical and chemical properties for a given system. In addition it shows that according to thermodynamics, there can be predictable differences in the composition of the same outermost phase layer prepared at the same conditions of temperature but under slightly different vapour pressures. 

The other method of monolayer transfer from the air/water interface onto solid substrates is illustrated in Figure 2. This method is called the Langmuir-Schaefer technique, or horizontal lift. It was developed in 1938 by I. Langmuir and V. Schaefer for deposition of protein layers. Prepared substrate horizontally touches the monolayer, and the layer transfers itself onto the substrate surface. The method is often used for the deposition of rigid monolayers and for protein monolayers, hi both cases the apphcation of the Lang-muir-Blodgett method produces defective films. 

Preparation of an uncontaminated surface of an aqueous solution is very difficult. Even minute traces of adsorbable organic impurities strongly influence the surface potential of water. Cleaning of the aqueous surface (e.g., by siphoning off the surface layer) is usually necessary, while for organic solutions it is usually not needed. ... 

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