Surface coating methods

See also Powder coating processes Spray coating processes discrete surface-coating methods, 7 23-24... 

Karl C. Vrancken is presently a researcher at the Laboratory of Inorganic Chemistry (University of Antwerp). In this position he substantiated the development of the Chemical Surface Coating method. In his young career as a Doctor in Sciences, he gained full expertise in organosilane chemistry. His current work is concerned with surface modifications and advanced materials preparation. 

For protein immobilization the most commonly used method is the EDC-NHS affinity ligand coupling chemistry as described for DNA bonding to glass substrates. An advanced surface coating method for protein microarrays was developed by the company MicroSurfaces. A polyiethylene glycol) (PEG) surface coating. 

Ti02-coated medical-grade AlSl 304 stainless steel provides an effective antimicrobial surface coating method for medical implements, thereby reducing the risk of hospital-acquired infection, and in particular infections caused by Staphylococcus aureus and Escherichia coli (Chung et al., 2008). 

Polyelectrolytes are usually used in membrane modification through the surface coating method. Among the two most important membrane surface modification methods, coating has more advantages over grafting for the following reasons ... 

In knife-over-roll or blade coating, the coating material is placed on the fabric surface behind a knife, or doctor blade, and metered according to the gap set between the blade and the fabric surface. This method is used to apply thick coatings of highly viscous materials such as pastes, plastisols, or foams. 

Numerous schemes can be devised to classify deposition processes. The scheme used herein is based on the dimensions of the depositing species, ie, atoms and molecules, softened particles, Hquid droplets, bulk quantities, or the use of a surface-modification process (1,2). Coating methods are as foHow (2) ... 

Wavelength dispersive x-ray fluorescence spectrometric (xrf) methods using the titanium line at 0.2570 nm may be employed for the determination of significant levels of titanium only by carefiil matrix-matching. However, xrf methods can also be used for semiquantitative determination of titanium in a variety of products, eg, plastics. Xrf is also widely used for the determination of minor components, such as those present in the surface coating, in titanium dioxide pigments. 

The second approach, that of surface coating, is more difficult, and that means more expensive. But it is often worth it. Hard, corrosion resistant layers of alloys rich in tungsten, cobalt, chromium or nickel can be sprayed onto surfaces, but a refinishing process is almost always necessary to restore the dimensional tolerances. Hard ceramic coatings such as AbO, Cr203, TiC, or TiN can be deposited by plasma methods and these not only give wear resistance but resistance to oxidation and... 

A final practical note involves instrument intensity measurement calibrations. The intensity measurement is self-calibrating relative to the incident beam from the source. However, measurements typically have a dynamic range of 10 -10 , and care must be taken to insure the detection system is linear. A method of calibrating the scatterometer is to characterize a diffuse reflector having a known scattering characteristic. For example, a surface coated with BaS04 makes a nearly Lambertian scatterer, which has a BRDF of 1/Jt at all angles. 

In modem manufacturing methods the oil is sometimes reacted directly with the glycerol to form a monoglyceride and this is then reacted with the acid to form the alkyd resin. When the resulting surface coating is applied to the substrate the molecules are substantially linear. However, in the presence of certain driers such as lead soaps there is oxidative cross-linking via the unsaturated group in the side chain and the resin hardens. 

In Section 4.3 several recently developed and experimental surface preparation methods for steel such as conversion coatings, plasma spray and sol-gel that attempt to simultaneously improve durability and bond strength over grit blasting will be discussed. 

This method is generally not capable of achieving a uniform standard of cleanliness on structural steel. It is not effective in removing intact mill scale or corrosion products from pitted surfaces. The durability of subsequent coats is therefore variable and unpredictable, and depends on the thoroughness of the operation and the exact nature of the contaminants left on the surface. The method should be confined to non-aggressive environments or where short-term durability is economically acceptable. 

The main protective method against atmospheric catastrophic attack is surface coatings of silicides, and aluminides. ... 

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