Aluminized film

Ng, M.-F. Cima, M. J. 1997. Fleteroepitaxial growth of lanthanum aluminate films derived from mixed metal nitrates. J. Mat. Res. 12 1306-1314. 

FIGURE 8.3 A typical aluminized steel surface following the polymer slurry method at 800°C in air. Any of the methods mentioned in this section about aluminized films will produce similar reaction layers. Ease of processing and cost may dictate which method is preferred for a given application. 

The majority of metals and alloys available depend for their resistance to corrosion on the properties of an oxide film or corrosion product which is formed initially by the corrosion process. In many cases the protectiveness of the oxide film is determined by its stability in aqueous solutions in a specific pH range, either chemically dissolving to form aquocations at lower pH values or complex anions (aluminate, ferroate, plumbate, zincate, etc.) at higher pH values (Fig. 2.22). An important property of the chemical is therefore the pH value that it develops when dissolved in water. For many materials and many chemicals this is the overriding factor and in many cases... 

A large number of electrolytic treatments of magnesium, anodic or a.c., have been developed, in which adherent white or grey films consisting of fluoride, oxide, hydroxide, aluminate or basic carbonate are deposited from alkaline solutions containing caustic alkali, alkali carbonates, phosphates, pyrophosphates, cyanides, aluminates, oxalates, silicates, borates, etc. Some films are thin, and some are relatively thick. All are more or less absorbent and act as good bases for paint, though none contributes appreciable inhibition. All can, however, absorb chromates with consequent improvement of protective efficiency. 

Focusing collectors are usually cast acrylic Fresnel lenses, or mirrors of aluminized polyester film in frames of aluminum. These reflectors are either enclosed in a bubble of poly(vinyl fluoride) film, or under polycarbonate glazing, which may be covered with a fluorocarbon film to reduce the reflectivity. The absorbers for active systems are copper or aluminum since the temperatures are too high (325—370°C) for plastics. The frames, however, can be molded ABS, high density polyethylene or polyurethane, either solid or structural foam. Polybutylene or chlorinated PVC can be used for piping hot water, and tanks can be made of either reinforced polyester or blow- or rotational-molded, high density polyethylene (12—15). 

Metallic coalings arc mnsi often selected lor protective function. Decorative ability is a common secondary function. Most coalings applied by Itoi dipping, such as galvanising or aluminizing, use a film of a more chemically reactive meial over a less reactive material such as iron alloy These are sacrificial coatings because the zinc or aluminum slowly dissolves instead of the underlying steel. 

Figure 1 Schematic representation of the aluminized Mylar surface. The polymer side of the film is used for the adsorption studies.

Figure 4 shows a representative IRAS spectra for a CO-1.5 film cast from a chloroform solution on an aluminized glass slide. The band frequencies and mode assignments are given in Table L These band assignments have been made using an analysis of a similar polymer (11). In addition to the symmetric and asymmetric CH2... 

Because the CdTe detector was not visible through the aluminized mylar film, it was necessary to check for proper... 

Reduction of O2 Plasma Treated Polypropylene Film. The oxygen plasma treated foils were stirred under N2 at room temperature in 12 ml dry THF and 3 ml of 1 M diborane solution for 18 hours. The foils were removed and immersed in an alkaline H2O2 and THF for 2 hours. Then, the foils were washed with THF, water (thrice) and with methanol. The modified foils were dried and stored in a desiccator. The reduction with LiAlH4 was performed in ether for 2 hours. Vitride (SDMA-Sodium dihydrobis(2-methoxyethoxy)aluminate) was processed in toluene for 2 hours and then the reaction product was hydrolized with NaOH. 

Dacron fiber is used to make fabric and tire cord, and Mylar film is used to make magnetic recording tape. Mylar film is strong, flexible, and resistant to ultraviolet degradation. Aluminized Mylar was used to make the Echo satellites, huge balloons that were put into orbit around the Earth as giant reflectors in the early 1960s. Polyethylene terephthalate) is also blow-molded to make plastic soft-drink bottles that are sold by the billions each year. 

If in the case of aluminized silicone we were able to evidence a drastic difference between sputtering and evaporation, it happens not to be the case for aluminized PET (13). Our preliminary results on this latter polymer indeed show no marked differences between the two deposition processes, both giving strong chemical interaction. By contrast we have also observed that with noble metals such as Au, no chemical interaction is taking place with silicone substrate with both deposition processes. This tells us that the nature of the polymer substrate and of the metal are most important for the interfacial and adhesive properties. The fundamental parameter seems to be the reactivity of both constituents of the interface. It has been confirmed by Pireaux et al. that the carboxylic function is one of the most reactive surface entity (14) and indeed for PET, the adsorption site for the Al atoms is found to be the carboxylic function (13). During this interaction, Al is oxidized and the diffusion of O into the Al film can occur. 

Interfaces of calcium aluminate cements with aggregates were discussed in Chapter 10. The interfacial zone between Portland cement paste and steel has been studied by SEM, using various techniques of specimen preparation (e.g. A31,B153). The major features observed have been substantial deposits of CH and, further away from the interface, a relatively weak, porous zone. Bentur ct al. (B135) also reported the occurrence of a duplex film. Interfaces of cement or CjS pastes with zinc (A32,T58) or copper (T58) have been studied. 

Lanthanide aluminates (LnAlOJ are of interest as buffer layers in controlling the overgrowth of various perovskite films and as alternative gate dielectrics to Si02. Using the singlesource heterometallic lanthanide aluminum isopropoxide precursors [LnAl(OPr )6(HOPr )]2... 

Figure 6.24 The crystal structure of [LnAl(OPd)6(HOPr )]2 (Ln = La, Pr, Nd), a single-source precursor to corresponding lanthanide aluminates (LnAlO ) [50]. (Redrawn fromT.D. Manning etal., Deposition of LaAlOs films by liquid injection MOCVD using a new [La-Al] single source alkoxide precursor, Journal of Materials Chemistry, 15, 3384-3387, 2005.)...

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