Copper coatings applications

New Fibers Textile Corp. Taiwan. Development, manufacture, and marketing of a range of specialty silver and copper-coated fibers and filaments for high-performance technical and industrial textile and nonwoven fabrics in clean room, protection, filtration, geotechnical, carpet, and specialty apparel applications. Extensive technical information... 

Other near-suiface applications have included the implantation profiles of phosphorus in iron and FeO [283] TiN and copper coatings on steel [284] chromate layers on aluminum [285] and implantation profiles of phosphorus and boron in iron and nickel [286]. 

An alternative to the current methods is the use of a conducting polymer as an electrode for direct electrolytic metallization of copper. IBM demonstrated the use of polyaniline in this application [88]. Because of its solubility, the polymer can be directly deposited onto a PCB by a dip-coating process. In one study [88], a PCB was coated with a thick ( 1 /xm) layer of polyaniline applied from an aqueous acetic acid solution. Today, as a result of the many soluble polyaniline derivatives that have been developed, a variety of solvents including water can be used to apply the polymer. The polyaniline-coated board was electrolytically copper plated. As can be seen in Fig. 32.23b, the copper started to plate on the hole wall from the two contact sides and grew inward until the copper fronts met at the center of the hole wall. As the plating process continued, a thicker, uniform copper coating deposited on the polyaniline surface. 

The polysulphides are frequently used in casting mixes and to a less extent in coating, laminating and adhesive applications. Their value in casting and encapsulation lies mainly with their low curing shrinkage and flexibility in the cured state. Their tendency to corrode copper and the somewhat inferior electric insulation properties of the blends does lead to certain limitations. 

As indicated in Table 31.4, the potential of ICPs is in somewhat esoteric applications. In some instances the potential has reached commercial realisation. For example, coating the walls of boreholes in circuit boards before electroplating with copper involves fewer stages than with older established processes and is claimed to be cost effective, faster and simpler. ICPs are also now being marketed in Japan for use in solid electrolyte conductors. 

Although transformers suitable for other industrial installations are generally suitable for producing applications, certain options may be desirable— primarily due to environmental considerations. At locations subject to harsh environmental conditions, and particularly at locations subject to washdown with high-pressure hoses, non-ventilated enclosures are desirable, if not necessary. Likewise, at locations subjected to salt water and salt-laden air, it often is desirable to specify copper windings and lead wires. Most manufacturers provide standard units with aluminum windings and lead wires. Even if aluminum coils are used, it is almost always desirable to require stranded copper lead wires. This will lessen corrosion and loose terminal problems when transformers arc interconnected to the facility electrical system with copper conductors. If the transformers are to be installed outdoors in corrosive environments, cases should be of corrosion-resistant material (e.g., stainless steel) or be provided with an exterior coating suitable for the location. 

Cathodic protection applications in fresh water include use of ferrite-coated niobium , and the more usual platinum-coated niobium . Platinised niobium anodes have been used in seawater, underground and in deep wells " and niobium connectors have been used for joining current leads Excellent service has been reported in open-seawater, where anodic potentials of up to 120V are not deleterious, but crevice corrosion can occur at 20 to 40V due to local surface damage, impurities such as copper and iron, and under deposits or in mud ... 

Platinised titanium These anodes are usually in the form of titanium rod, tube or wire with a coating of platinum 2-5 to 5-0 tm thick. Diameters are generally in the range 3 to 25 mm. In order to reduce the voltage drop in very long anodes, a copper cored variety is available. Platinised titanium anodes may also be used in mesh or plain sheet form and can be fabricated to suit particular applications. 

Conductive Polymers Anodes currently available consist of a conductive-polymer graphite material coated on to a multistrand copper conductor. The polymer provides an active surface but shields the conductor from chemical attack. A non-conductive outer braid may be used to give abrasion resistance and avoid direct contact with the cathode. The finished anode has the appearance of an electric cable and is claimed to have applications for buried/immersed structures and for internal protection of tanks, etc. Anode current densities are typically given as 14-30mAm ... 

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