The Metallization Process

Metallizers with external unwind and rewind facilities have also become known. Here the web is transported into and out of the vacuum chamber through locks. Because of demanding requirements of instruments and apparatus, these coaters have not gained acceptance for coating of polymer webs. They are successfully used in semi-continuous processes, for example glass coating. 

The following section briefly describes the three most commonly used evaporation methods used in reel-to-reel metallization. 

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Uses. Alkah metal and ammonium fluoroborates are used mainly for the high temperature fluxing action required by the metals processing industries (see Metal surface treatments Welding). The tendency toward BF dissociation at elevated temperatures inhibits oxidation in magnesium casting and aluminum alloy heat treatment. 

Molten Salt Extraction Salts Plutonium and Americium Recovery. We have demonstrated the ability to successfully strip the plutonium from the MSE salts. The resulting metal product now contains as much as 10% americium and as a result cannot be fed directly into the metal processing sequence. To use the plutonium we must remove the americium. 

Metal preparation. This comprises any and all of the metal processing steps preparatory to applying the enamel slip. Usually this includes cleaning, pickling, and applying a nickel flash or chemical coating. 

In Fig. 12.16, the metallized wafer, in contrast to the non-metallized one, shows a large excess contribution in the heat capacity. The excess heat capacity cannot be attributed to the term CM of eq. (12.11), since the material of the two wafers is the same, and they were produced in the same run of neutron irradiation. Instead, this excess is to be attributed to the metallization process. 

In contrast to the potassium naphthalene dianion, EN gives rise to a dianionic species at concentrations higher than 0.03 mol.l- (Table II). Furthermore the EN dianion is unable to transfer one electron to another naphthalene molecule. These sharp differences are to be attributed to the participation of the -ethyl group in the metalation process. 

AQUATECH Systems can help the metal processing industry ... 

Fig. 2. Recycling of aluminum beverage cans and other scrap saves nearly 95% of the energy required when producing the virgin metal from ore. Approximately 50% of the metal processed in 1990 was recycled from scrap. (Reynolds Aluminum Recycling Company)...

Large-scale leaching also occurs in the metal processing induslries. where useful metals frequently occur mixed with large quantities of unwanted matter, and leaching is used lo remove Ihe metals as soluble salts. 

The most interesting feature of this method, reviewed by Stepanov,62 is the ease with which the halogen atom is replaced by a hydroxyl group during the metallization process. This was first observed as long ago as 1931 when Delfs63 obtained the copper complex of 2-(2-hydroxy-naphthyl-l-azo)phenol-4-sulfonic acid (47) by heating an aqueous solution of l-chloro-2-(2-hydroxynaphthyl-l-azo)benzene-4-sulfonic acid (48), copper sulfate, sodium hydroxide and ammonia at 80 °C for 1 hour. 

For more than 25 years, vacuum metallization of polymer webs with aluminum has been carried out on an industrial scale. Initially used to coat PVC for decorative purposes, the metallization of synthetic materials is today first and foremost used to produce functional coatings [1]. In the course of the past few years, metals other than aluminum have gained increasing importance in the metallization of polymer webs. The development of the metallization process was, and still is, subject to two requirements, namely higher quality and lower cost. Higher quality means ... 

In summary, good barrier properties can only be achieved by optimizing all the factors affecting the metallization process. Under these conditions, metallized layer barrier properties will be excellent. Superior barrier properties may only be achieved by using multi-layer structures. Such ultra high barrier films, formed from metallized A1 sandwiched between two acrylate layers, were first reported in 2000 [13]. 

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