Material systems coating materials

The number of material systems that can be used for nanolayer coatings is vktuaHy unHmited. Any refractory hard material can be used as the hard material compatible metal can be used as the tough material. Examples of material systems for nanocoatings include the foUowing ... 

The fluid dehvery in an air-spray system can be pressure or suction fed. In a pressure-fed system, the fluid is brought to the atomizer under positive pressure generated with an external pump, a gas pressure over the coating material in a tank, or an elevation head. In a suction system, the annular flow of air around the fluid tip generates sufficient vacuum to aspirate the coating material from a container through a fluid tube and into the air stream. In this case, the paint supply is normally located in a small cup attached to the spray device to keep the elevation differential and frictional pressure drop in the fluid-supply tube small. 

Earlier material systems were screened epoxies, but both laminatable dry-film and Hquid uv photoimageable coatings are finding wide acceptance. These radiation-cured coatings offer high resolution and registration accuracy, and can be either epoxies or epoxy acrylates. 

Release coatings are important components of pressure sensitive adhesive (PSA) products such as tapes and labels [1]. Release materials are coated onto the backside of PSA tape backings (often called low adhesion backsizes or LABs in this form) to provide the desired tape roll unwind force. They are also coated onto various substrates to form release liners for PSA products such as labels and transfer tapes. Typically the thickness of the release coating is less than 1 p,m, and often times less than 0.1 jLm. Release coatings can be thought of as the PSA delivery system, providing a controlled unwind or release force and protecting the adhesive from contamination and unintentional contact until it is applied. 

P.J. Tunturi and J. Radio. Expert system for selection of materials and coatings in ventilation sysrem.s in pulp and paper indu.stry. In A. J.insson and L. Olander, eds. Ventilation 94 Proceedings of the 4th International Symposium on Ventilation for Contaminant Control, pp. 149-1.52, 1994. 

Although the initial choice of coating material applied for reasons (b) or (c) may be dictated by the particular properties required, the corrosion behaviour of the composite metal coating/metal substrate system must also be taken into consideration in so far as it may affect the maintenance of the desired properties. Consequently, in all cases where protective metal coatings are used the corrosion performance of both coating and substrate require careful consideration. 

Improved processes and quality control have helped to establish these new coating materials but the care necessary for successful use has to be appreciated. Sections 11.1 and 11.2 have shown how necessary it is to remove millscale before coating and how scale-free surfaces may still retain seeds of further corrosion even when apparently cleaned well. The percentage of premature failures with sophisticated systems is still high, even on apparently well-prepared surfaces and there is a strong case for effective inspection at each stage of coating operations. 

Flares. A flare compn is described in Refs 15 16 contg powd Mg, Na perchlorate, and a binder which can be cast and cured, and which has a luminous intensity of 50,500 candle-secs/g Incendiaries. A mixt of 1 OOg of Na perchlorate and 58.7g of powd Al has a Qr of 2751cal/g and can be used as a filler for incendiary bombs (Ref 6). A proc is described in Ref 14 for coating Na perchlorate with Al, and the use of the coated material in incendiaries Photo flash Compositions. Mixts of 80% Ca metal and 20% Na perchlorate and 80% Ca, 10% Na perchlorate, and 10% Na nitrate have been examined as expl photoflash compns for both sea level and high altitude use (Ref 13) Refs 1) Gmelin, System No 21 (1928), 408 Supp Part 1 (1964), 180 2) H.H. Willard ... 

Almost all urethane materials are synthesized without the use of solvents or water as diluents or earners and are referred to as being 100% solids. This is true of all foams and elastomers. There are many products, however, which do utilize solvents or water, and these are known as solvent-borne and waterborne systems, respectively. In the past, many coatings, adhesives, and binders were formulated using a solvent to reduce viscosity and/or ease application. However, the use of volatile solvents has been dramatically curtailed in favor of more environmentally friendly water (see Section 4.1.3), and now there are many aqueous coatings, adhesives, and associated raw materials. Hydrophilic raw materials capable of being dispersed in water are called water reducible (or water dispersible), meaning they are sufficiently hydrophilic so as to be readily emulsified in water to form stable colloidal dispersions. 

In the manufacture of coating materials, paints, varnishes, lacquers, dyestuff pigments, binding materials, and binders, surfactants are of great importance. Most of the systems used in these fields are dispersed. Therefore surfactants can accelerate the preparations of dispersions and improve their stability. For rewetting processes, like the so-called flush process, besides other anionic surfactants sulfosuccinates are also used. 

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