Single layer coatings

Different TiN-, TiC-, and TiAlN-based single layer coatings on steel alloyed with Cr, Ni, Mn, and WC were prepared by use of the cold vapor deposition technique. The thickness of the coatings varied from 2.7 to 6.4 pm. 

Figure 2.17 Cumulative vancomycin release of single-layer coatings as a function of antibiotic concentration. (Reproduced from ref. 12, with permission.)...

Endeavor and ZoMaxx are being developed by Medtronic and Abbott Vascular, respectively. The common components shared by these two DES are the PC copolymers and the drug Zotarolimus (previously known as ABT-578). The difference is that Endeavor uses a thin single-layer coating which results in fast in vivo release of the drug (22), whereas ZoMaxx employs additional PC topcoat to reduce in vivo drug elution kinetics (23). 

Fig. 15.8. Distribution of charged particles in dense single-layer coating composed of mono-disperse nanoparticles (numerical simulation for dielectric constants e = 1 and e = 10, T = 100°C). Z is the charge multiplicity of nanoparticles.

The design equations for predicting the performance of single layer coatings are uncomplicated. For the case of a continuous plane wave incident normal (perpendicular) to the surface, the reflectivity and transmissibility of a layer can be shown to be ... 

Circular Contact Area on Single Layer (Coating) on Half-Space... 

It is expedient to apply single-layer coatings of powder polymer mixtures with Cl under regimes corresponding to the bounds of zones I and II. When it is necessary to create a Cl concentration gradient across the coating thickness, it is applied at the end of zone II where the fluidized bed is most separated. 

Water-soluble Cl significantly improve the protective ability of oil, alkyd, alkyd-styrene and alkyd-nitrocellulose coatings (Fig. 3.41), for example, 3wt% of water-soluble potassium chromate guanidine. Cl has been introduced into the lacquer base, after which a 20-pm-thick single-layer coat has been applied on a plate of low-carbon steel (St 2). The time until the appearance of corrosion traces under the coating has been recorded on exposure to atmosphere at 100% humidity and a temperature of T = 18-25°C. The results presented in Fig. 3.38 prove that the introduction of this Cl has perceptibly improved the anticorrosion properties of lacquer coatings [1]. 

Chem. Descrip. Aqueous of dispersion of styrene/2-ethylhe) acrylate/ acrylic acid/acrylamide copolymer (50%), emulsifier Uses Binder for anticonosion coatings, topcoats, and single-layer coatings... 

Uses Binder for anticorrosion coatings, primers, topcoats, single-layer coatings... 

Forward roll, (meniscus roll coating), single layer coating, 1-50 mPa s wet thickness 10-2000 im accuracy + 8% speed 0.05-1 m/s with maximum speed 2.5 m/s shear stress 10-1000 1/s. Not as precise as reverse roll. Thickness dependent on roll rpm, viscosity and gap. 

Reverse roU, single layer coating, 1-500 000 mPa s thickness 5-400 pm accuracy + 5% speed 0.02-8 m/s shear stress 1000-100000 1/s. More precise than forward roll. Web is usually closed and OK for materials that are easily deformed. Example jersey knits, plastic films. Probably the most versatile. 

RoU with knife single layer coating, 1000-10 000 mPa.s thickness 50-2500 pm wet coat web speed 0.05-2 m/s. Simple, low cost. Propensity for streaking. 

RoU with air knife single layer coating 5-500 mPa s thickness 0.1-120 pm accuracy + 5 % maximum speed 8.2 m/s. OK for pigmented surfaces. Usually not used, prefer slide, curtain or extrusion. Examples book, litho, clay-coated sheet. Spin coating thin films 20 nm + 10%. 

Figure 15. AFM topography images (1x1 jm ) of Zr02 single layer coatings of different roughness properties left sample A right sample B.

Figure 16. AFM topography image (1x1 pm ) of an ultra-hydrophobic AI2O3 single layer coating, deposited by magnetron sputtering.

Figure 20. Comparison of wetting parameter Kjj within specific spatial frequency decades for Z1O2 and AI2O3 single layer coatings.

As just stated, two requirements need to be fulfilled for exact cancellation of reflected beams by a single-layer coating, i.e. the two reflections have to be out of phase by exactly tt, and exactly the same intensity is required. Consequently, a single-layer AR coating must be an odd number of quarter wavelengths to achieve the correct phase relation for wave cancellation. In addition, the refractive index of the thin-film medium has to obey the relation Mair < TF < S-... 

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